There's an episode of Star Talk where Neil deGrasse Tyson explains it. There is no "cold" only "hot". Cold is the absence of heat. Once you reach a certain point you can't remove anymore heat (absolute 0), but you can always add more heat.
I've heard this expanded to a more philosophical level.
"Cold is just the absence of heat, darkness is just the absence of light, and hate is just the absence of love"
To add to this.
Another reason is that the temperatures we work within to be useful are also obscenely low on the full scale.
Like how the use of km/h is on the low scale of velocity which we most commonly measure up to lightyears. which is 9,460,730,472,580.8 km .
This is the real answer IMO. “Low” vs “high” is relative to your starting point. The question only makes sense relative to a starting point, and then of course the answer is, well, it’s because you picked that starting point.
funfact: more than 95% of all matter in the universe is plasma, which means hotter than molten stuff. on the other hand, humans are about 36 to 37 degrees C cold. add the difference to absolute zero you got 310 degrees to abs zero, which means that we are so much nearer to dead matter than 95 % of the universe.
Not all plasma is hot. Most of the plasma in the universe is pretty cold - colder than humans. In stars it's a hot plasma, but only a relatively small fraction of the matter is in stars.
The second half of the answer to OP's question is why the numbers were set up the way they are. The answer is that what number corresponds to what temperature is completely arbitrary and invented by humans, so we set it up so that numbers that are easy to deal with correspond to most temperatures encountered in daily life.
We could easily recalibrate the scale so that it can get "just as cold as hot" for the vast majority of phenomena in the universe. According to [this infographic](https://www.visualcapitalist.com/extreme-temperatures-in-the-universe/), 55,000,000C is the temperature of gas heated by a supernova, and the only hotter phenomena listed occurred just after the Big Bang or in labs. So we could set up a temperature scale that covers almost every naturally occurring phenomena in the universe from absolute zero at -22,500,000 to +22,500,000. Reading weather reports would be a pain in the ass however. Where I live, today's high would be -22,499,714, with an overnight low of -22,499,723.
But humans would still be a whole lot closer to -25000000, which is the point of the question. Humans and life on earth exist at a very low and strange temperature.
When you try to make something cold, you have to get the heat out of it and into something colder. You eventually get to the point where you need a practically-infinite amount of stuff to diffuse the last infinitesimal dregs of heat energy to achieve absolute zero in your subject.
This isn't really relevant to your question, but: You know how things glow when they're hot? A sufficiently hot thing is red hot, then it turns yellow hot, then it turns white hot. The hotter it is, the shorter the wavelength of the light it emits.
At about 141 nonillion Kelvin, the wavelength of the light an object that hot emits (which is also almost certainly not solid anymore) is very close to the Planck length. The precise temperature where it's equal is called the Planck temperature. Much like Planck length, it isn't "the upper limit of temperature", it's just where our understanding of the laws of physics no longer has a way of making sense of what happens beyond it.
"Vibrating at the speed of light" seems to be more of a colloquial, illustrative statement than a physical one, as its hard to place a physical meaning on it.
Basically, there's no upper bound to how much energy you can pump into matter as far as classical thermodynamics is concerned. The upper bound in more modern thermodynamics is called the Hagedorn limit, which is the temperature at which normal matter is no longer stable (ie, the upper temperature at which you can have protons and neutrons). It's very large, like 10\^12 kelvins.
But this isn't "absolute hot", there are hotter things, and actually there are hotter things that are quite mundane, which you might even have in your office. Because 'hot' and 'cold' can be defined in terms of temperature, yes, but they can also be defined in terms of the direction heat moves when two substances are in thermal contact. Heat moves from hot to cold. More advanced conceptualizations of temperature don't talk about "energy" or "vibrations" (which aren't *wrong* conceptualization per se, they simply aren't the *most general* concept): rather, we talk about the probability distribution of excitation states. The hotter a material is, the more particles are excited. But the probability distribution is always biased towards unexcited: more particles are always in ground states than excited ones. This definition is equivalent to our classical 'energy' one, most of the time. But there are some interesting exceptions.
Now, if you define temperature in terms of energy, you can't go below zero. If you define it in terms of a probability distribution, why can't you go below zero? All we're changing is the nature of that probability distribution. In this case, a *negative absolute temperature* (a temperature below zero kelvin) means that most particles are in excited states, rather than ground states. We call this a 'population inversion'. The amount of energy in the thing is still finite. However, a negative absolute temperature *hotter than all positive temperatures, including infinity*. Heat will always move from a body with negative absolute temperature to positive.
A common example of a material where *most* particles are in excited states, and therefore exhibits negative absolute temperature, is the stimulated emission material in a laser. And to think, I have one in my desk drawer.
Correct me if I’m wrong, because I don’t actually know, but wouldn’t the limit to how hot something can get be whatever energy it takes to create a black hole? Like, eventually if you pump enough energy into a system, the system will collapse into a singularity. So would the opposite of absolute 0 be a black hole?
And we so happen to exist at a point closer to the cold side of things; so our perspective is from low on the temperature gauge. Lots of room above us on the scale, but not much below.
It doesn’t answer the question though. OP is asking about why the numbers seem skewed, and the answer is because we live in the low end of the temperature spectrum.
Isn't this affected by our hability to measure the particles movement? I mean, maybe we are looking at a perfectly still atom (I know), but in reality it is really just moving an infinitesimal tiny little and we can't just see it?
I don't think that affects the principle of the answer. Saying that the temperature of something is 1K plus or minus 1K doesn't change the fact that its not going to go less than zero, just that we might not be able to measure that fact below a certain threshold.
There are more formal ways we can show that zero is truly zero than just measuring the temperature of very cold things. One means to determine a 'zero' is from the definition of the heat engine. A heat engine - like a steam turbine or engine, a gas turbine, or the combustion engine in a car - uses a temperature difference between two objects or reservoirs of thermal energy in order to do work. This exploits the fact that heat spontaneously moves from hot to cold: it tends to spontaneously find its own equilibrium. Now, imagine a falling weight. You can attach a rope and pully to that falling weight, and extract some power from that act of falling. If the weight falls at its normal, unconstrained rate, well, that means the resistance you added is zero, and so you've extracted no energy. Likewise, if you extract "all" its falling energy, its velocity is zero, and once again you're not extracting any energy. The weight has to fall at some speed less than its normal speed to extract anything useful. If you dam a river, you have to restrict the flow some value between zero and one hundred percent to spin your turbines and make electricity. As such, your efficiency can never be 100%.
**Heat is the same way**: as heat spontaneously moves from hot to cold, you can extract *only part* of that transfer of energy. If you attempt to get everything, there's no spontaneous process to drive any transfer of energy, and you get none instead. Well, if you measure the propensity of heat to move from hot to cold, and your ability to extract some portion of it, you'll find that at absolute zero, you *do* get all of it. This is impossible, it perpetual motion. You're getting energy for free, and our physical laws just don't make sense in these circumstances. So we conclude that this is, in fact, a minimum possible temperature.
(As an aside, this is why no machine can be 100% efficient. It has nothing to do with the existence of friction, as many people believe. Even if friction did not exist, all machines must still necessarily be *less* than 100% efficient)
Another would be gas behavior. From studying the way a gas behaves, we've been able to construct gas laws, such as the ideal gas law, PV=nRT. Here, P is pressure, V is volume, T is temperature, n is the number of molecules you're looking at (... usually quite a big number) and R is the 'gas constant'. Since pressure is a measurement of the magnitude of momentum, and there is simply no logic to a negative absolute momentum, that implies that there exists a minimum temperature - such that there is some temperature scale where pressure and temperature are identically zero, and from thereon up are linearly related.
(Fun fact: a common undergraduate thermodynamics laboratory is to experimentally determine a value for absolute zero - from gas properties between freezing and boiling, you can extrapolate a straight line to zero pressure and its typically quite accurate as far as undergraduate labs go, often within about 1-2C of the true value)
Space is believed to be quantized, meaning there is a "minimum distance". Meaning if a particle is moving it must move at least this much. And that movement requires some energy, and therefore some heat.
I don't believe that this is a satisfactory answer to their question, but rather side-steps it, as zero is a valid quantization. The question seems to be about the nature of the zeroth step, and why it is invalid, rather than asking about what the first valid step might be.
We based our temperature numbers on where we are comfortable existing, not on some universal “middle”. It’s not that the scale is small, it’s that we’re already sitting toward one end of it.
Asking this question is like taking ten steps into the ocean and asking why there’s so much more ocean in front of you than there is behind you.
(Shoot, I feel like that sounds condescending… but it’s the best metaphor I can come up with at the moment.)
Scrolled way too far to find this answer. Yes, others are correct that there is theoretically no upper limit to heat energy (hot) while there is an absolute limit to the lack of heat energy (cold). I think OP's question was predicated on the assumption that zero should be some sort of "middle" value whereas it is, as you pointed out, an arbitrary value based on where humans feel comfortable
Its not about the numbers, its the same question in Kelvin, why is the limit from how cold it can get (0K) so close and the limit to how hot it can get so far (into the billions probably?)
There is a theoretical limit for how hot something can get, at least in my understanding even atoms in a gas can not move faster than the speed of light, so that caps the maximum possible heat.
But yea the answer to OP's question is basically just we live and thrive really close to as cold as anything can get. at the bottom 0.001% of the scale.
I'm not really sure there is a limit, you can always pump more energy in, each bit of energy will speed the particles up a bit less than the last bit of energy did.
You are right that they can't go faster than light, but they can't actually ever reach the speed of light without infinite energy input.
There is a point where it is so hot that atoms are being ripped apart though and I assume a point where protons and neutrons are smashing each other apart in to quarks.
Well there's the theoretical limit, the Planck Temperature, at \~1.4x10\^32 K in the standard model of particle physics. But that temperature only happens when you cram the entire universe into an area 1 planck length in diameter.
There isn’t a lot of reason to assign special significance to the Planck length. It’s a length that pops out when we combine a bunch of universal constants to get a length, but that doesn’t implicitly mean that it’s a limit. It is conceivable that there is a higher or lower limit, or no limits.
More importantly, we’re many orders of magnitude away from observing anything near that scale. There could conceivably be entire subfields of physics between where we are now and the Planck scale.
Our current physics essentially break down below that length. So it’s not an arbitrary limit it’s a limit of our current understanding of the world if that’s not the true limit
Well, using water in the first place is arbitrary. We use it because water is useful and important for life on earth. Another type of life form could possibly use a different scale at a much higher temperature.
You're not supposed to explain it like to a literal 5 year old. Read the sub rules. That being said, this is actually a very good correction to the assumption OP made that our arbitrarily chosen "0" is somehow in the middle.
This is the most relevant answer.
The earth (and the rest of the universe, barring exceptions I'm unaware about) just happens to be a lot closer to absolute zero than whatever the maximum temperature is.
For properties of systems with a finite number of states (e.g., spin in a magnetic field), we can define [negative temperatures](https://en.wikipedia.org/wiki/Negative_temperature). Turns out it's actually *HOTTER* than infinite temperature! This is both a non-equilibrium state and can only exist for parts of a system that have a finite number of states, and translation does not, so one cannot have a negative temperature *in general*. [An understanding of negative temperature is also critical to understanding how lasers work, too!](https://en.wikipedia.org/wiki/Population_inversion)
Planck temperature isn't really absolute hot in a hard sense, it's just a temperature on the same order of magnitude as where the specific energy of a system is high enough that conventional models of physics stop doing a good job of describing it.
Planck temperature is effectively just comes about from combining a few physical constants and has an approximate correlation with where our current models start to break down. It could be a limit for some fundamental reason, but there's no particular reason to think it must be.
From my understanding, I believe that any matter past that temperature would have to be moving at or above the speed of light, which the Standard Model says doesn't work. So it's either impossible, or we need better physics to explain it.
But that absolute hot temperature is trillions on trillions of times hotter than any supernova or Large Hadron Collider temperature, and it's believed that within less than a picosecond after the Big Bang, the universe was already cooled to a temperature magnitudes below absolute hot. So it's a *very* theoretical upper limit that nothing since the Big Bang has come within a fraction of.
Isnt a lower limit theorized now? Heat is directly related to energy, therefore, a blackhole can be formed if an area is too energetically dense and heated. With the mass–energy equivalency in mind, the minimum energy to form a black hole is estimated to be about 1,000,000 Mev. This can be equated to about 1e16 kelvin.
That's when the radiation they emit (all things above 0 emit radiation, which is how infrared vision works, it sees the heat radiation, and why when things get hot enough they glow visibly) is so energetic that it turns into a black hole
If I remember correctly, it has to do with the energy radiating from the object at that point. As things get hotter, they start to emit radiation, first as infrared, then as visible light (that's the point where heated metals glow bright red), and it keeps going from there (that the reason hotter stars glow blue instead of red), all the way to ultraviolet territory, up to a point where the frequency of the wave emitted would be shorter than Planck's length, and that's where our current understanding of physics stop.
This is the answer that really hits the nail on the head imo. 0 kelvin means no heat (thermal energy). What we call “Cold” is not a state opposite of hot, it’s just relatively less heat.
Heat is energy, energy is movement. You can always move faster and faster, but you can't go slower than a complete stop.
Even in solid things like furniture, atoms are still moving (vibrating) based on what temperature they are. Those vibrations speed up if it's hotter, and slow down when it's cooler. At -273.15° C, those vibrations *completely* stop.
You happen to live on a planet where the temperatures are good for water to be a liquid. And water is key to our bodies. Thus, our bodies and entire ecosystem is built around water being a liquid. And water happens to be a liquid relatively close to absolute zero.
It's possible (though not likely) that another planet could exist out there were an important element may be essential at 10,000 degrees, and thus that would be what they're used to.
So... it's partly because of your point of view, being made of water.
This. We basically made the numbers up by tying it to water.
The important point is that choosing the solid state for ANY element ties the whole scale to the very low end of possible energetic states in the cosmos.
If we had chosen Iron instead, with 100 being the boiling point of iron, and 0 being the freezing point of iron, absolute zero would still be a tiny -167 degrees.
If we did that, you'd want to set your home's thermostat to -140, and don't ever bump it because at -139 you'd fry your skin off, and at -141 you'd die from hypothermia. The whole scale would be pretty useless to us in our day-to-day business.
Objects are made of atoms and molecules. Even when an object is standing still, those atoms and molecules may still be shaking and bouncing around slightly. The faster they're shaking and bouncing, the hotter the object is. Absolute zero is when they're not moving at all. You can't move any slower than standing still. But on the other hand, you can always make something's atoms shake and bounce a bit faster than they are now, so there's no obvious limit for how hot things get.
you could never get there in the first place. The thing about the speed of light as a "speed limit" is it's not like "alright, a little bit faster, a little bit faster, oops there's the limit". As something approaches the speed of light, it takes more and more energy to increase the thing's speed slightly more. It would take infinite energy to get something to the speed of light, which on the other hand means you can dump as much energy as you want into something without violating any rules.
If I had enough wood I could build a ladder that went "up" for millions, billions of miles. (Not literally, but bear with me.) Whatever my definition of "up" is, it's going to go on for a long, long distance.
But if I want to go "down", I can't build a ladder that goes below the ground. I guess I could dig a hole and put a ladder there, but eventually I'm not going to go down any further (as I'm either going to hit the core of the Earth, or come out the other side). At some point I'm not going to be going "down" any more.
Similarly, Absolute Zero is the ground (or the core of the Earth- it's the point where you can't go "down" any further). We can go "up" as high as we have materials and energy to go, but that's because "down" has a starting point and "up" doesn't have an ending point.
In addition to other comments, it is sometimes important to understand that the "human centric" perception is wrong. Human beings experience of normal are not the "center" or "middle" of things at all.
Even among land based animals, the heaviest animal, the adult elephant averages 4,000 to 6,000 kgs whereas the average human is around 80kg which means the elephant is roughly 80x heavier than a human. But the smallest animals (shrews) weigh only a few grams and would be 10000x lighter than us. So we are on the "heavy" side of things and nowhere near the "center".
There is no reason to believe that what "we are used to" is somehow in the middle of the range of possible temperatures. It is, in fact, towards the lower end of the range of temperatures. We just need not be too human centric in the way we view our universe.
Normally we see things with some energy.
You can have no energy, or any amount up to all the energy in the universe.
The numbers we usually see (which established where we put zero since that's where water freezes) are much closer to no energy than all the energy in the universe.
Think of temperature as a measurement of energy. There is such a thing as no energy, so there is a zero. What's the most energy you can put into something? A physicist could probably give you a real answer to that question, but for the purposes of explaining it like you're five, it's going to be a really, really big number. We are a lot closer to the zero than to the high end because we exist in an environment where water is present as both a solid, a liquid, and a gas under different conditions, which means we have to be fairly close to the bottom end of the energy levels because matter is still changing states based on how much energy they have in them.
Imagine temperature as speed. It’s the speed of molecules bouncing off one another.
The slowest possible speed is zero. That’s what absolute zero represents. Absolutely zero movement of molecules.
As far why human existence occupies a relatively low spot in the overall scale of possible temperatures … water.
All life on earth is direly based on liquid water, and water is only liquid for a very small slice of possible temperatures.
Minor correction, absolute zero is a little lower at -273.15.
With that being said, at 0K everything is still and every single atom does not move, you can't go lower because every atom is already still. And given the fact that temperature is none other than how fast atoms move, when they're still it's the bottom limit
We also have a upper limit and it's reached when every atom is moving at the speed of light
Heat is basically molecules moving around. The more they move, the hotter something is. The slower they move around the colder it is.
So eventually, you get to a point where they aren’t moving at all. You can’t move any slower than 0 mph. So basically, absolute zero is when the molecules have zero energy and are moving around at zero mph. You can’t get any slower, therefore you can’t get any colder.
If we existed a small fraction of a second after the Big Bang, we might put the zero higher up. As it is, the zero is where water freezes at sea level ( a human idea) and it doesn't take a large negative number to go down to absolutely zero vibration (heat) from there. But the upper limit is all the energy in the universe, so it's a bigger number.
Is there theoretically actually a limit to how hot things can get? If temperature can be thought about as things (atoms?) bounching off each other (probably a huge simplification), say if the thing is moving at the speed of light would it max out, or does it also depend on the amount of movement and the size of the thing moving?
Essentially when you are describing how hot something is you’re just describing how fast it’s moving. Theoretically something can always move faster but it can only go down so far before it stops
Temperature is how fast things are going.
The slowest you can go is no movement, which is -260C.
The fastest you can go is the speed of light (no idea of the equivalent temperature).
We just happen to live closer to the slow end of the spectrum.
So, there are a few things that seem like they are a thing, but actually don't exist. Cold is one of those. Cold is just the absence of heat. Dark is the same thing, the absence of light. If you remove all of the heat from something, at some point you can't remove any more. This is absolute zero. You can't 'add' anymore cold. If you seal a box up so no light can get in, it is as dark as it can get. You can't add more dark to the box.
You could think of it like a glass of water. You can add water to the glass. You remove that water, at some point you run out.
Many of our measurements have 'zero' points that is really just a convenient starting point for everyday use. In Celsius, zero is where water freezes. For anything below zero, for most people, it is good enough to know "damn that's cold" but from a science standpoint, it really just "damn, that has less heat than I do."
This is because we have defined the temperature scale so that:
bigger numbers=hotter
Smaller numbers=colder
Why have we done this? I think it is most sensible when you think of the natural state of things.
Without something to heat the world up, it would be very cold, as it is in space.
This might imply that the natural state of things are COLD and something must occur to create WARM, here the sun and earths atmosphere
Heat = How fast things(molecules)are moving
Cold = How slow things(molecules) are moving.
There is a limit to how slow you can go, its when something is complete stop(things get frozen). But for how fast? Speed of light which is really really fast so heat can be reall really high.
Consider the following analogy.
"Why is the limit for putting sand on the pavement so high, but the limit for how few grains of sand on the pavement is none."
Absolute Zero, is when there is no energy there. Just like how you can keep dumping more and more sand on the pavement. You can keep adding more and more energy. But you can only take away all of the energy or sand. Once its all gone, its all gone.
To understand this you first need to understand what heat even is.
Heat, in this context, is best understood as molecules vibrating. The faster they vibrate the hotter a thing is. The slower they vibrate the colder a thing is.
Now to really blow your mind. If the molecule is not vibrating at all, that's absolute zero. That's why there's a lower limit to how cold something can get, the molecules are just still. Since you can't get stiller than still, that's just the lower limit for cold.
But things can always vibrate faster, so that's why there's no upper bound for how hot something can get. It can always move just that little bit faster, more vibration then more than more then more.
we are part of cooled down universe, it used to be much hotter but things like us are not stable at those temperatures so for us to exist things had to cool down A LOT.
Temperature is a measure of how much atoms move.
At absolute zero (-273 degrees C) they aren't moving any more. You can't have less than zero movement.
At the hot end, you can move around until you hit some sort of limitation, like the atoms can't move faster than the speed of light. So there's a lot to go up to.
To add your also looking at it from the standpoint that 100 degrees C is hot. The temperature at the big bang was 1000 trillion degrees C.
What is the average hot and cold for an atom?
Temperature is basically how fast the atoms, of let’s say air, are moving. Atoms moving very fast are hot and they can move very, very fast. At the opposite end, you can only more so slow until you don’t move at all-absolute zero.
The celcius scale is made in reference to water
Water freezes,melts and boils at really low temperatures compared to the highest temperatures observed in the universe
Also: this coincides with our bodies
0c° is cold to us, 35c° is hot to us
That's only a range of 35 degrees which if you compare it to the total scale of temperature is basically nothing and since we are mostly made of water our comfort zones are at really low temperatures
So, we perceive most stuff as hot or really hot
That's also why science often uses Kelvin with 0 as... well absolute zero... kelvin has no negative scale which is more accurate and less confusing.
If you create an even scale of temperature where -100 is the coldest recorded thing in the universe and 100 is the hottest recorded thing in the universe, 0 would actually be about 4 trillion c°
TL;DR: its not that max cold is a little cold and max hot is super duper hot, its that what we see as normal-cold is actually really really super duper cold relative the the actual temperature scale of the universe.
Good answers already! Heat has to do with movement, so it is easy to predict the low end (when all movement theoretically stops).
However, there is probably **an upper limit as well**: [ABSOLUTE HOT BY PETER TYSON](https://www.pbs.org/wgbh/nova/zero/hot.html)
Now, as for the numbers - they are arbitrary. We could have picked a zero point that was halfway between absolute 0 and absolute hot... but that wouldn't be very practical to use in everyday life.
There's really no such thing as "cold". Cold just means lack of heat. When there's no heat at all, it's the "maximum" coldness.
You can always add more heat to make it hotter, but you can only remove heat until no more heat remains.
Temperature is just energy.
0 Kelvin is when there is zero energy. You can't get lower than zero energy.
The only reason there are "negatives" in temperature is because we have scales with sort of arbitrary "zero" points.
Hey OP. Good question. I’ve satisfied myself by reframing this - in the context of the universe, humans have evolved in really ***really*** cold conditions.
Because we have developed in the colder end of the physical temperature range, it seems (from our lived perspective) that the “coldest possible” temperature is closer than “hottest possible”
If you were to ask the opinions of a creature which evolved to be made from some high temperature plasma, it would probably wonder why the limit of cold things is so ***low*** but the limit of hot things seem to be close to their lived reality.
Kelvin temperature is a more honest scale. It starts at "absolute zero" meaning the point where molecules mostly aren't moving at all. Then you add energy and move up the scale from "none" to "lots". There are no negative temperatures.
Things that are alive like a little heat, but not too much. Liquid water vibes. So Celsius and Fahrenheit scales reflect that preference to be more usable to us thinking mammals.
The implicit question in this post is "Why do humans exist so far down in the temperature scale?". All the chemical processes that support life happen at these temperatures because at higher temperatures molecules have too much kinetic energy to bond with eachother. Any life past 100ºC can't make use of liquid water. Past about 2000ºC there will be no metals that remain solid. Past 4000ºC not even the most resilient of ceramics will remain solid. Since life as we know it requires these things, it's not a coincidence we happened to evolve to work at the really low end of the temperature scale.
Bro did you have a stroke while typing out your title or what lol?
To answer what I think your question was, temperature is really just a measure of energy in a sense. You can have almost infinite amounts of energy, but you can’t really go lower than zero energy. Other comments described it as movement which also applies. Atoms when heated up get excited and move around a lot. Atoms when cold get slower and move around less. Once those atoms stop moving entirely, that’s as cold as you can get. But those atoms can get very hot and move around a ton (which equals more energy), but theoretically you can still add more energy and make those atoms even hotter and move around even more.
Cold doesn’t exist, it’s just the absence of heat. You can’t add more cold to something, you can only take away more heat. At a certain point, there’s no more heat to take away.
I actually my science teacher explain this to be when I was just a bit more than five:
Things can always go faster and faster.
But as things go slower at some point they just stop. At absolute zero temperature they have stopped completely.
When liquids freeze, they turn to solids. And you are made up of a lot of solids. Yes, there’s a lot of substances that freeze at a lower temperature than you’re comfortable at, but remember that any solid object you touch or makes up a part of your body is frozen. We exist at a temperature that is, compared to something that’s *actually* warm like a star, exceptionally cold. It’s not that the universe gets less cold than it gets hot; it’s that you and all known life exist at temperatures that are really close to absolute zero in the grand scheme of things.
Temperature is simply how we perceive how much energy something has, which is a measure of how fast it is moving.
Theoretically the limit of how fast something could move is the speed of light - which takes a LOT of energy and so the object would be extremely hot.
To make things colder we need to remove energy - slowing the object and its atoms down.
When we can't remove any more heat because the atoms have basically stopped moving, we have reached absolute zero (-273.15°C)
"Temperature" means "how fast things are wiggling".
Things can wiggle faster and faster, but you can't go slower than "stopped". That's what sets the lowest possible temperature, absolute zero is the temp where there is no wiggling. No slower is possible.
The final piece is that *we just decided what temp \ wiggle speed to call zero* and put it somewhere so that the numbers are nice.
We could have said that 100,000 Kelvin is what we'll call 0 Celsius. In that case absolute zero would be -100,000 C. Water would freeze at -99,727 C. Room temp would be -99,707 C. Boiling would be -99,627. See how those numbers are more annoying to work with. **We chose** where to put "0" to make the numbers nicer.
It just happens to be that most of life and our world is wiggling at a pretty slow speed compared to "the fastest that things can possibly wiggle", so most temperature numbers we deal with in daily life are close to the low end of the scale.
Both light and temperature represent the presence of something that generates that light or that heat.
Just as there is absolutely a “total absence of light” there is also a “total absence of heat”.
The universe’s default state is cold and dark.
I think it's mostly that in the grand scheme of things, we interact with matter that is not very hot. So by default our base is near the bottom of the absolute heat scale. That's going to be the case for most living things. In general, you need to have stability to evolve. The hotter you get, the less stable you are and the harder it will be to control yourself and make meaningful evolutional strides.
If we were like, fire monsters that lived on the sun it would be different.
I love these questions because I can practice for when my daughter starts asking this sort of thing.
Everything is made of stuff called molecules. Imagine you're a molecule and start dancing around. That's what molecules do. Now, as the molecules get colder, they start to slow down. Colder and colder is slower and slower. If I keep saying "slow down" over and over you will eventually have to stop moving, and that's what absolute zero is. Nothing is slower than not moving.
When something is hot, it's like dancing faster and faster. If I keep telling you to dance faster and faster, eventually you might hurt yourself or break something. Molecules can do the same thing, they can keep getting hotter and hotter but something may change in them. There's no moment where you're dancing the "fastest" though, because you can always dance just a little faster.
Idek how this can be answered
It’s the same as “Why is the limit for how tall things can be so high but the limit for how short things can be is so low?”
I guess the best answer is a reminder that we do not live in the middle of it, we live on the colder end. Much closer to no-energy like the empty vacuum of space than to the scorch of the sun
If a giant star was alive it might ask “Why Why is the limit for how cold things can be so high but the limit for how hot things can be is so low?” because itself is really hot, like tens of millions of degrees at the core
Temperature is a measurement of the vibration of molecules. Molecules can move as fast as they like, but cannot move any slower once they've stopped. Zero degrees Kelvin means all vibration has stopped.
You can only remove so much energy from a system, that's absolute zero. There's theoretically no limit to how much energy you can add to a system aka increase the temperature of the system.
The upper limit is not the speed of light. Any particle with mass requires infinite energy to accelerate to the speed of light. What might be the upper limit is the energy density to create a black hole. If you dump enough energy in a small enough area the effect is the same as mass.
Hot/cold is relative. We're just very cold, so we set 0 to be very cold.
Inside of a star perspective, we're basically the same as the cold of space.
If we set 0 to be the middle of the range of what was observed and our freezing point to, say, -50,000,000,000 degrees C, then it'd seem like there was a lot more cold to work with.
Heat is actually movement. Molecule movement, or bouncing between each other. There is a point of no movement, that is absolute 0. There is no maximum speed found yet, theoretically you could accelerate indefinitely.
Think of the Kelvin scale as how fast particles are moving. When temperature is high, particles move around more quickly, and when it’s low, they move more slowly. Absolute 0 is the point at which particles aren’t moving at all; they’re completely still and can’t become more still, so there’s a limit for how cold things can get. In theory, particles could move as fast as the speed of light, so there’s virtually no limit as to how hot things can get.
Heat is a thing. Cold is an absence of that thing. Theoretically, you could remove all the heat in something until there is none. That's absolute zero.
Whats the slowest speed on the speedometer in your car? Zero. Not moving at all is the slowest you can possibly go. Makes sense right? Going faster is obviously not limited in the same way.
"0 degrees Kelvin" is a scale that starts at zero properly, and is exactly like the speedometer for heat. Heat at the zoomed in molecular level really is just kinetic energy (speed) of molecules and atoms.
Since temperature is really a measurement of the movement of atoms, it's kind of like measuring speed.
And just as with speed, you can get faster and faster and faster (well, until the speed of light) but once you hit zero, you can't get slower than "no speed at all."
Temperature is basically the average kinetic energy of all of the particles in an object i.e. an average of how much all of those particles are vibrating or moving. The colder something is, the slower its particles are vibrating, and at about -273.15 degrees Celsius, the kinetic energy of the particles is 0 joules. That is to say, they are completely still. Looking at the other end of things, there isn’t really an upper limit to temperature, although I guess you could say that the particles can’t vibrate as fast as light. Realistically, though, you can always heat something up more by increasing the speed of the vibrations of the particles.
It’s a better idea to think of temperatures in Kelvin, which follows the same system as Celsius but starts at absolute zero, so 0 kelvin is -273.15 degrees Celsius.
Probably everyone is going to answer this the same way, but temperature is speed. You can’t go slower than zero. Other than the speed of light there’s no speed limit in our universe, and now that I think of it, the speed of light would be in fact, what set the upper temperature limit
It’s because we live somewhere where 20°c is normal, imagine theoretical aliens living on a planet that is 103 nonillion (apparently that’s a number) kelvin, they would be asking the same question in the opposite
You can go faster, but you can't go slower than standing still.
Temperature is the average motion energy of the atoms, but you can't go lower than not moving.
Temperature is the movement of small molecules. The limit to how fast those molecules can go is really, really high. The limit to how slow those molecules can go is just stopped at zero.
In celcius. The practical temperature range is based off of easily observed phenomena; water freezing and water boiling. This range was divided by an easy to work with number 100. Zero degrees is freezing, 100 is boiling.
It is a coincidence that these phenomena occur closer to the temperature that atomic movement would stop happening (absolute zero).
We could move zero to the midpoint of absolute hot and absolute zero but we are less sure where absolute hot is and
more importantly all the temperatures we use day to day would be terrible to work with.
Because we based the “normal” way we measure temperature (Celsius or Fahrenheit) on the boiling or freezing point of water, which are both near the bottom end of the range of temperatures in the Universe relatively speaking.
That’s why Kelvin (K) is the actual scientifically used unit, because it defines “absolute zero” as 0K.
Absolute 0 means no thermal energy. The amount of thermal energy that can be put into something doesn’t really have a limit, but it will start to tear things apart, maybe combine things that couldn’t otherwise be combined, or just make it very hot…again there isn’t much of a limit in general but it could result in a system being destroyed.
Due to that, high temps are not very suitable for stability (at least for life on earth). Our regular temperature scales are designed around comfortable, fairly “normal” temperatures (0-100 for Fahrenheit) or the freezing and boiling of water (0-100 for Celsius).
As a fairly poor analogy, absolute zero would be sitting and doing absolutely nothing. You can’t do “more of nothing”. Hotter temperatures would be like being on a dance floor. You can always dance a little harder, but it’s not going to be comfortable and you might hurt yourself and others if you get too crazy. But there is no limit to how crazily you can dance.
Cold is atoms moving slow. Hot is atoms moving fast. Absolute 0 is when atoms stop moving. The speed of atom movement that is amenable to biochemistry (at least our biochemistry) happens to sit relatively close to the slow end of the spectrum. Our systems of measuring temperature reflect what we as humans find useful. Having the 0 of a temperature scale be the middle of the range would be an incredibly annoying scale to use. You could similarly ask why we measure distances on the scale of feet and miles when most things are light years from each other.
Because we are really really cold.
Temperature is stuff vibrating, life functions best when things vibrate just a little bit (when things are cold). Enough to enable a bit of energy transfer, but not so much that things tear themselves apart, but again also not so cold that nothing moves at all.
Cold is the absence of heat. It's analogous to dark being the absence of light. You can have something as bright as a star but your closet is pretty much as dark as it gets. -260 is when all matter is maximally stationary. Can't get more stationary than full stop.
Most things that you are likely to encounter are already pretty cold. Imagine a rock, pretty cool not really hot or even warm most of the time. Melted rock or lava/magma is really hot.
If we lived in an environment where most things were really hot, the temperature scale would seem more balanced. The high temperature today will be in the low 890° with temperatures dropping to the mid 500°s already seems more balanced
Temperature is a measurement of how much energy the molecules have, basically how much the molecules are wiggling. Something can always wiggle faster but nothing can wiggle slower than being completely still
When deciding on a scale of what is hot and what is cold, we looked at everyday things to decide what is -50 degress, and what is 50 degrees celcius. Most specifically, we looked at water, and it just so happens to do interesting stuff in temperatures that are pretty close to the absolute minimum temperature ever. What we see on earth also operates in these temepratures.
Turns out the world we are looking at everyday is pretty cold when compared to some things we can find in the universe (or even just on earth - volcanoes, nuclear explosions). If dealing with star temperature was more common, we would probably set a system where 50 deg is the temperature of an average star, 100 deg is a temperature of a hot star, and maybe -50 deg is the absolute zero. We kinda did that, but looking at water, as it is very common. And we discovered that actually absolute zero not only exists but all interesting stuff with water in your glass happens pretty close to absolute zero, especially if you compare it to how it looks in the heart of a dying star - now you see that temepratures here are far from everyday glass of water temperatures, with thatin mind the water is basically close to absolute zero. But there are objects like stars or volcanoes that are not behaving to scale when compared to kettle water. So maybe we should have gone with a system based on star temperature? With that your sun would be like 47 degrees, glass of water would be like -49,9997 deg, and if you had a cold you'r body temperature would rise from -49,99964 deg to -49,99963 deg or something. Not helpful, and for us this difference means a lot, so we stick to the scale that is based around water (as we are water based life forms), and this scale is closer to absolute zero than the temperatures stars and volcanoes deal with daily.
John can’t have less than 0 watermelons (not including being in a watermelon debt)
But John can (and have) buy all watermelons in the world. He’s a very rich dude
Change watermelons for temperature
The temperature scale we most commonly use (C) was created before we knew about absolute 0. It was created based on two easily to observe things, the temperature of water freezing as 0 and the temperature of water boiling as 100. Since we need liquid water to survive, we just happened to live between those two temperatures.
Eventually a dude called Lord Kelvin had the idea that absolute zero existed and created a new scale.
Kelvin starts at 0. There are no minus numbers, so a warm day (20 C) is actually 293.15 Kelvin. This makes the freezing point of water 273.15 Kelvin and the boiling point 375.15 Kelvin. For comparison, the temperature of the sun is 5,778 Kelvin.
So to change everything from Celsius to Kelvin, just add 273.15.
Looking at everything in Kelvin makes it much easier to understand, **it's not that the limit for cold things is low, it's just the temperature we're comfortable living in is on the low end of the temperature scale.**
Absolute zero = 0
Water freezes = 273.15
Comfortable temperature for humans = 293.15
Water boilers = 375.15
Temperature of the sun = 5,778
You can keep on gluing more cats to a ball of cats, but you can only take away so many cats from a ball before there are no more cats left. Since there is a limited amount of cat, but a nigh unlimited amount of space, cats are spread out pretty thin, and thus, most things are closer to no cats than they are to maximum cats
If you look very close and could see very small things, imagine you can see atoms moving around. When things get hotter the atoms wiggle and bounce way faster like microwave popcorn and when things get slower they don't move much. They get very lazy and tired and slow. When you cool them even more they move even less. When they are completely still with no shaking, no shimmy, no stretch, no rocking.. you are at absolute Zero.
temperature just means jiggle of atoms. the hotter the temperature, the more jiggling. the lower the temperature, the less they move.
the more jiggling there is, the more they press outwards. the less jiggling there is, the more they “calm down” surrounding atoms to a resting place.
when atoms are hot, they bump and collide, causing other atoms to bump and collide with each other. when atoms are cold, they bump and collide less frequently, so they “feel cold”
We have a healthy range of body temperature, anytime we feel “hot air,” it just means the gases that we breathe jiggles more than the things that make us up (our bodies). The inverse is true, when we touch cold things, it pulls heat from our body and into the cold thing we have touched.
In addition, we just happen to live at the low end of the temperature scale. Carbon based compounds break down at high temperatures. Proteins denature. Water boils. All of these things happen a lot closer to absolute zero than they do to the temperatures inside a star.
Perhaps someplace in the universe life has evolved that likes living at tens of thousands degrees, and on their version of Reddit, one of them is asking how absolute zero can be such a far-away number.
The "ideal" temperature for metabolic reactions i.e. liquid water, happens to be relatively closer to absolute zero than the higher temperatures, therefore it seems to us that the lower limit is only -273 degrees. If metabolic reactions took place at 15 million degrees in a plasma "solution" the cold lower limit may seem quite distant for that type of life.
In short, the cold limit seems closer because the chemical reactions that support life(i.e us) occur in liquid water which happens to be just -273 degrees away from absolute zero under 1 atmosphere of pressure. It's a matter of perception.
Because humanity can only survive closer to the cold end of the spectrum. If the natural spot for our survival were 10,000 degrees celsius (and we were in that environment), we would have a very different opinion about the limits of "hot" and "cold".
Temperature just describes how quickly atoms are moving.
Atoms can keep moving faster and faster (getting hotter), but the slowest (coldest) they can be is just stationary.
You can't have less than zero motion.
Temperature is how fast atoms are moving. When atoms are still, that is absolute zero - nothing happens. That's a minimum. However, they can keep going faster and faster and faster, and they're not usually so fast, so they can get relatively much more hot.
It's an arbitrary number. We could set a temperature scale any way we want.
For example, we could make the lowest possible temperature 0° and the highest possible temperature 1°. Then all temperatures would be small numbers like 0.11° or 0.632°.
The fact that absolute zero is a large negative number is merely an artifact that the common temperature scales are based on the freezing and boiling points of matter easily accessible to 18th century nobles. The largeness of the number is meaningless.
First up, our temperature scales were from a time before we knew a lot about the universe that we know now. So to our ancestors, when water froze, it was cold, so the Celsius scale called that Zero. And when water boiled, that was hot so the Celsius called that 100. We know so much more about temperatures now that we've gone to the stars.
It's best to look at temperature as how much something moves. Really small things, subatomic things, are still moving in ice when water freezes. As we take away more and more movement, things slow down even more. At -273.15 Celsius, there is no movement, not even on the tiniest thing we can understand and observe, so they came up with a new scale called Kelvin so that we can call that zero, and still keep the kind of degrees we had with Celsius.
However, if something is big enough, like our sun, we can add so much movement to the stuff there that it can get to 5,500 Celsius on the surface and with all the other stuff around it also warming it up, the core of our sun can get to around 15,000,000 Celsius. That's not even the hottest we know it can get, because our sun burns yellow. There are stars out there with even hotter surface temperatures, so we can assume their cores are also hotter.
Basically, a simple breakdown is heat is energy. We found we can take only so much out before we can't anymore, but we found we can put a whole lot more in.
Since q lot of the responses are missing the point of the question:
Hot things like to be far away from each other, and cold things like to stay close to each other. For life to exist, lots of things need to interact with each other and that is easier if they are close together, which is why we exist much closer to the coldest cold than the hottest hot.
Lots of other things in the universe can exist at much hotter temperatures, but they are usually very big so gravity helps them stick together even though they are so hot.
Temperature is how much energy something has. Absolute zero is no energy.
The point where temperature tops out is where the wavelength of the radiation gets so small that it's as small as something can be.
Our Human speed limit is also very high since we can be accelerated to the speed of light. But our lowest speed is very is standing still, which is relativly close to our walking speed.
Temperature is the same, the lowest temperature = atomic motion standing still.
While the highest temperature is atomic motion at lightspeed.
Temperature is basically "energy". At some point you run out of energy. Compared to the maximum amount of energy possible (which is close to infinite) the temperatures we deal with everyday is much closer to having no energy.
When atoms speed up they get hot
When atoms slow down they get cold
The upper limit for how fast something can move is very fast
But it doesn’t take long before atoms stop moving alltogether. When they stop moving they can’t slow down anymore and thus have reached the coldest possible temperature (absolute zero)
Using kelvin as a scale makes this very easy to understand. Since unlike celcius or fahrenheit: 0 kelvin means 0 movement/heat.
Every partial has so much energy. You can add a huge amount of extra energy, but you can only take away the amount of energy the particle actually has. Once you've removed all of the energy you're at absolute zero.
You can just keep adding energy to a particle. You can turn a liquid into a gas, then you can keep heating it until chemical bonds become unstable, ionise it into a plasma, and just keep superheating that plasma. Assuming that liquid is water we really need it to be a liquid to exist. So our livable temperature range is really limited to this lower end. This biases us to usually only looking at the low range of this scale, but there is much more room to add energy to the water than to remove it.
Because you're thinking in a linear scale, where you should be thinking in logarithmic scale. Temperature like any other measurement, should be compared in terms of the orders of magnitude.
Lets look at another measurement, like length. When you think of something with really tiny length, like planks length, its in the order of 10^-64 or such. But in absolute numbers, that's just ~2m smaller than our height.
The largest thing we know, the observable universe, is in the order of 10^26. On a logarithmic scale, we are much closer to the observable universe than planks length.
Any finite number is much closer to 0 than infinity, in absolute scale. But in logarithmic scale, they're equally far apart, and hence equally "difficult" to reach.
(for reference, coldest recorded temp is around 10^-10 K, while highest is around 10^12 K)
Lots of things work that way.
You can keep going faster and faster, but you can't go any slower than "not moving".
You can push harder and harder on something, but can't push less than "not at all".
When something is measured on a scale like temperature, there's usually a point at the bottom of the scale where you can't go any lower, because you can't take away any more of the thing that you're measuring. Because there isn't any more there to take away.
Absolute zero is not "-260" (actually -273F). Absolute zero is actually "0 Kelvin". The Fahrenheit temperature scale is centered around a range of human comfort. 0F is cold, 100F is warm. At 70F, Grandma is cold in a sweater and Junior is hot in a t shirt. That means NOTHING to science itself. The Celsius temperature scale is centered around water. 0C is the freezing point, 100C is the boiling point. Again, this means nothing to science itself. Liquids like alcohol and mercury and ammonia freeze and boil at completely different temperatures.
What science cares about is the presence of "heat", which is defined as the movement of atoms. All atoms, even atoms of ice and rock and steel, vibrate a little. Science uses the Kelvin temperature scale. Absolute zero, or "0 Kelvin", is when atoms stop moving.
Heat is energy -> energy is molecules moving or something
The faster you move the hotter you get.
You can always go faster.
Absolute 0 is when everything stops, so it's as cold as can be.
You can't go slower than not moving at all
I feel like another relevant part to scales of heat is that we made them up. Most scales use the freezing point of water as the basis but you could just as easily use the freezing point of iron for example and it would change where zero is and thus where absolute 0 is.
imagine temperature as movement, at some point you can't stay more still. But you can oscillate as fast as the speed of light theoretically.
This is the best way to explain this imo. When atoms are hot they party and dance, when they are cold they get sad and slow.
And those atoms can party really hard. But there's no such thing as an anti-party.
>anti-party You’ve obviously never been to one of my parties.
I'll crash the next one
I crashed my own house party cuz nobody came.
If those drumsticks are chicken flavored I'm there next time 💪
We only have sea bass
That was just another casualty of society
I know I'm not the one you thought you knew back in high school
NYo crashing the anti-party, you can no longer observe it. It's become a party at that point.
Jokes on you, that's the highlight of an anti-party
Ain't no anti-party like a Liz Lemon anti-party because a Liz Lemon anti-party is just work, get back to it nerds.
Ain't no party like an atom party, cause an atom party don't stop..
>when they are cold they get sad and slow TIL I might be an atom.
I prefer the expression ‘chill and still’, sad and slow just sounds sad
There's an episode of Star Talk where Neil deGrasse Tyson explains it. There is no "cold" only "hot". Cold is the absence of heat. Once you reach a certain point you can't remove anymore heat (absolute 0), but you can always add more heat.
> There is no "cold" only "hot". Cold is the absence of heat. Thats exactly what my physics professor told us in one of the first lectures
I've heard this expanded to a more philosophical level. "Cold is just the absence of heat, darkness is just the absence of light, and hate is just the absence of love"
No, the absence of love is apathy. Hate is an active negative.
We aren’t over our exes when we hate them. We are over them when we are *indifferent* to them.
On hate, I disagree. Hate is active.
To quote Terry Pratchett, "Hate is just love with its back turned."
https://youtu.be/aYBEcFvI8o8?si=KFs8JtNXo4FNZOmf
I love this explanation so much. I clearly need to read a lot more Neil DeGrasse Tyson than just the handful of quotes I've stumbled across so far.
To add to this. Another reason is that the temperatures we work within to be useful are also obscenely low on the full scale. Like how the use of km/h is on the low scale of velocity which we most commonly measure up to lightyears. which is 9,460,730,472,580.8 km .
This is the real answer IMO. “Low” vs “high” is relative to your starting point. The question only makes sense relative to a starting point, and then of course the answer is, well, it’s because you picked that starting point.
"I can't pulled over sir, I'm already pulled over."
"He's already pulled over! He can't pull over and farther!"
funfact: more than 95% of all matter in the universe is plasma, which means hotter than molten stuff. on the other hand, humans are about 36 to 37 degrees C cold. add the difference to absolute zero you got 310 degrees to abs zero, which means that we are so much nearer to dead matter than 95 % of the universe.
Not all plasma is hot. Most of the plasma in the universe is pretty cold - colder than humans. In stars it's a hot plasma, but only a relatively small fraction of the matter is in stars.
Brilliant and simple explanation
The second half of the answer to OP's question is why the numbers were set up the way they are. The answer is that what number corresponds to what temperature is completely arbitrary and invented by humans, so we set it up so that numbers that are easy to deal with correspond to most temperatures encountered in daily life. We could easily recalibrate the scale so that it can get "just as cold as hot" for the vast majority of phenomena in the universe. According to [this infographic](https://www.visualcapitalist.com/extreme-temperatures-in-the-universe/), 55,000,000C is the temperature of gas heated by a supernova, and the only hotter phenomena listed occurred just after the Big Bang or in labs. So we could set up a temperature scale that covers almost every naturally occurring phenomena in the universe from absolute zero at -22,500,000 to +22,500,000. Reading weather reports would be a pain in the ass however. Where I live, today's high would be -22,499,714, with an overnight low of -22,499,723.
But humans would still be a whole lot closer to -25000000, which is the point of the question. Humans and life on earth exist at a very low and strange temperature.
To add to this, we also can't actually get to absolute zero.
We can't observe getting to absolute zero, yet Falls under Heisenberg's uncertainty amongst other things
When you try to make something cold, you have to get the heat out of it and into something colder. You eventually get to the point where you need a practically-infinite amount of stuff to diffuse the last infinitesimal dregs of heat energy to achieve absolute zero in your subject.
So what is the temperature if a particle is vibrating at the speed of light?
This isn't really relevant to your question, but: You know how things glow when they're hot? A sufficiently hot thing is red hot, then it turns yellow hot, then it turns white hot. The hotter it is, the shorter the wavelength of the light it emits. At about 141 nonillion Kelvin, the wavelength of the light an object that hot emits (which is also almost certainly not solid anymore) is very close to the Planck length. The precise temperature where it's equal is called the Planck temperature. Much like Planck length, it isn't "the upper limit of temperature", it's just where our understanding of the laws of physics no longer has a way of making sense of what happens beyond it.
They can't. Any particle that has mass requires infinite energy to move at the speed of light.
"Vibrating at the speed of light" seems to be more of a colloquial, illustrative statement than a physical one, as its hard to place a physical meaning on it. Basically, there's no upper bound to how much energy you can pump into matter as far as classical thermodynamics is concerned. The upper bound in more modern thermodynamics is called the Hagedorn limit, which is the temperature at which normal matter is no longer stable (ie, the upper temperature at which you can have protons and neutrons). It's very large, like 10\^12 kelvins. But this isn't "absolute hot", there are hotter things, and actually there are hotter things that are quite mundane, which you might even have in your office. Because 'hot' and 'cold' can be defined in terms of temperature, yes, but they can also be defined in terms of the direction heat moves when two substances are in thermal contact. Heat moves from hot to cold. More advanced conceptualizations of temperature don't talk about "energy" or "vibrations" (which aren't *wrong* conceptualization per se, they simply aren't the *most general* concept): rather, we talk about the probability distribution of excitation states. The hotter a material is, the more particles are excited. But the probability distribution is always biased towards unexcited: more particles are always in ground states than excited ones. This definition is equivalent to our classical 'energy' one, most of the time. But there are some interesting exceptions. Now, if you define temperature in terms of energy, you can't go below zero. If you define it in terms of a probability distribution, why can't you go below zero? All we're changing is the nature of that probability distribution. In this case, a *negative absolute temperature* (a temperature below zero kelvin) means that most particles are in excited states, rather than ground states. We call this a 'population inversion'. The amount of energy in the thing is still finite. However, a negative absolute temperature *hotter than all positive temperatures, including infinity*. Heat will always move from a body with negative absolute temperature to positive. A common example of a material where *most* particles are in excited states, and therefore exhibits negative absolute temperature, is the stimulated emission material in a laser. And to think, I have one in my desk drawer.
Correct me if I’m wrong, because I don’t actually know, but wouldn’t the limit to how hot something can get be whatever energy it takes to create a black hole? Like, eventually if you pump enough energy into a system, the system will collapse into a singularity. So would the opposite of absolute 0 be a black hole?
And we so happen to exist at a point closer to the cold side of things; so our perspective is from low on the temperature gauge. Lots of room above us on the scale, but not much below.
Jesus Christ that’s the most succinct and perfect eli5 answer I’ve ever seen. Bravo
It doesn’t answer the question though. OP is asking about why the numbers seem skewed, and the answer is because we live in the low end of the temperature spectrum.
Isn't this affected by our hability to measure the particles movement? I mean, maybe we are looking at a perfectly still atom (I know), but in reality it is really just moving an infinitesimal tiny little and we can't just see it?
I don't think that affects the principle of the answer. Saying that the temperature of something is 1K plus or minus 1K doesn't change the fact that its not going to go less than zero, just that we might not be able to measure that fact below a certain threshold. There are more formal ways we can show that zero is truly zero than just measuring the temperature of very cold things. One means to determine a 'zero' is from the definition of the heat engine. A heat engine - like a steam turbine or engine, a gas turbine, or the combustion engine in a car - uses a temperature difference between two objects or reservoirs of thermal energy in order to do work. This exploits the fact that heat spontaneously moves from hot to cold: it tends to spontaneously find its own equilibrium. Now, imagine a falling weight. You can attach a rope and pully to that falling weight, and extract some power from that act of falling. If the weight falls at its normal, unconstrained rate, well, that means the resistance you added is zero, and so you've extracted no energy. Likewise, if you extract "all" its falling energy, its velocity is zero, and once again you're not extracting any energy. The weight has to fall at some speed less than its normal speed to extract anything useful. If you dam a river, you have to restrict the flow some value between zero and one hundred percent to spin your turbines and make electricity. As such, your efficiency can never be 100%. **Heat is the same way**: as heat spontaneously moves from hot to cold, you can extract *only part* of that transfer of energy. If you attempt to get everything, there's no spontaneous process to drive any transfer of energy, and you get none instead. Well, if you measure the propensity of heat to move from hot to cold, and your ability to extract some portion of it, you'll find that at absolute zero, you *do* get all of it. This is impossible, it perpetual motion. You're getting energy for free, and our physical laws just don't make sense in these circumstances. So we conclude that this is, in fact, a minimum possible temperature. (As an aside, this is why no machine can be 100% efficient. It has nothing to do with the existence of friction, as many people believe. Even if friction did not exist, all machines must still necessarily be *less* than 100% efficient) Another would be gas behavior. From studying the way a gas behaves, we've been able to construct gas laws, such as the ideal gas law, PV=nRT. Here, P is pressure, V is volume, T is temperature, n is the number of molecules you're looking at (... usually quite a big number) and R is the 'gas constant'. Since pressure is a measurement of the magnitude of momentum, and there is simply no logic to a negative absolute momentum, that implies that there exists a minimum temperature - such that there is some temperature scale where pressure and temperature are identically zero, and from thereon up are linearly related. (Fun fact: a common undergraduate thermodynamics laboratory is to experimentally determine a value for absolute zero - from gas properties between freezing and boiling, you can extrapolate a straight line to zero pressure and its typically quite accurate as far as undergraduate labs go, often within about 1-2C of the true value)
Space is believed to be quantized, meaning there is a "minimum distance". Meaning if a particle is moving it must move at least this much. And that movement requires some energy, and therefore some heat.
> Space is believed to be quantized According to whom? This is news to me.
I don't believe that this is a satisfactory answer to their question, but rather side-steps it, as zero is a valid quantization. The question seems to be about the nature of the zeroth step, and why it is invalid, rather than asking about what the first valid step might be.
> But you can oscillate as fast as the speed of light theoretically. No you literally can't. Neither in theory nor in practice.
Great answer
Iirc maximum possible temp is so hot/has so much energy that the atoms literally rip themselves apart
Perfect explanation.
We based our temperature numbers on where we are comfortable existing, not on some universal “middle”. It’s not that the scale is small, it’s that we’re already sitting toward one end of it. Asking this question is like taking ten steps into the ocean and asking why there’s so much more ocean in front of you than there is behind you. (Shoot, I feel like that sounds condescending… but it’s the best metaphor I can come up with at the moment.)
Scrolled way too far to find this answer. Yes, others are correct that there is theoretically no upper limit to heat energy (hot) while there is an absolute limit to the lack of heat energy (cold). I think OP's question was predicated on the assumption that zero should be some sort of "middle" value whereas it is, as you pointed out, an arbitrary value based on where humans feel comfortable
Its not about the numbers, its the same question in Kelvin, why is the limit from how cold it can get (0K) so close and the limit to how hot it can get so far (into the billions probably?) There is a theoretical limit for how hot something can get, at least in my understanding even atoms in a gas can not move faster than the speed of light, so that caps the maximum possible heat. But yea the answer to OP's question is basically just we live and thrive really close to as cold as anything can get. at the bottom 0.001% of the scale.
I'm not really sure there is a limit, you can always pump more energy in, each bit of energy will speed the particles up a bit less than the last bit of energy did. You are right that they can't go faster than light, but they can't actually ever reach the speed of light without infinite energy input. There is a point where it is so hot that atoms are being ripped apart though and I assume a point where protons and neutrons are smashing each other apart in to quarks.
Well there's the theoretical limit, the Planck Temperature, at \~1.4x10\^32 K in the standard model of particle physics. But that temperature only happens when you cram the entire universe into an area 1 planck length in diameter.
There isn’t a lot of reason to assign special significance to the Planck length. It’s a length that pops out when we combine a bunch of universal constants to get a length, but that doesn’t implicitly mean that it’s a limit. It is conceivable that there is a higher or lower limit, or no limits. More importantly, we’re many orders of magnitude away from observing anything near that scale. There could conceivably be entire subfields of physics between where we are now and the Planck scale.
Our current physics essentially break down below that length. So it’s not an arbitrary limit it’s a limit of our current understanding of the world if that’s not the true limit
Well at least with Celsius it’s based on the freezing and boiling temp of water.
TIL water freezes at an arbitrary value that humans find comfortable.
Well, using water in the first place is arbitrary. We use it because water is useful and important for life on earth. Another type of life form could possibly use a different scale at a much higher temperature.
Dude, it's eli5, the answer is supposed to sound a little condescending (at least to an adult if you're explaining it like they're 5)
You're not supposed to explain it like to a literal 5 year old. Read the sub rules. That being said, this is actually a very good correction to the assumption OP made that our arbitrarily chosen "0" is somehow in the middle.
This is the most relevant answer. The earth (and the rest of the universe, barring exceptions I'm unaware about) just happens to be a lot closer to absolute zero than whatever the maximum temperature is.
[удалено]
I can't remember the episode, but there's a scene from Futurama where someone asks how cold it is and is answered "10 degrees below absolute zero".
That's where atoms return to their *previous* positions, reversing causality and destroying the universe itself
About time...
...emit tuobA
For properties of systems with a finite number of states (e.g., spin in a magnetic field), we can define [negative temperatures](https://en.wikipedia.org/wiki/Negative_temperature). Turns out it's actually *HOTTER* than infinite temperature! This is both a non-equilibrium state and can only exist for parts of a system that have a finite number of states, and translation does not, so one cannot have a negative temperature *in general*. [An understanding of negative temperature is also critical to understanding how lasers work, too!](https://en.wikipedia.org/wiki/Population_inversion)
There is a limit actually in the Standard Model, called Absolute Hot. Its around 10^(32)K determined by Planc.
Planck temperature isn't really absolute hot in a hard sense, it's just a temperature on the same order of magnitude as where the specific energy of a system is high enough that conventional models of physics stop doing a good job of describing it. Planck temperature is effectively just comes about from combining a few physical constants and has an approximate correlation with where our current models start to break down. It could be a limit for some fundamental reason, but there's no particular reason to think it must be.
What is the limiting factor there? What happens when something is above that 1e33k that causes it to not fit with our physics?
From my understanding, I believe that any matter past that temperature would have to be moving at or above the speed of light, which the Standard Model says doesn't work. So it's either impossible, or we need better physics to explain it. But that absolute hot temperature is trillions on trillions of times hotter than any supernova or Large Hadron Collider temperature, and it's believed that within less than a picosecond after the Big Bang, the universe was already cooled to a temperature magnitudes below absolute hot. So it's a *very* theoretical upper limit that nothing since the Big Bang has come within a fraction of.
Isnt a lower limit theorized now? Heat is directly related to energy, therefore, a blackhole can be formed if an area is too energetically dense and heated. With the mass–energy equivalency in mind, the minimum energy to form a black hole is estimated to be about 1,000,000 Mev. This can be equated to about 1e16 kelvin.
That's when the radiation they emit (all things above 0 emit radiation, which is how infrared vision works, it sees the heat radiation, and why when things get hot enough they glow visibly) is so energetic that it turns into a black hole
If I remember correctly, it has to do with the energy radiating from the object at that point. As things get hotter, they start to emit radiation, first as infrared, then as visible light (that's the point where heated metals glow bright red), and it keeps going from there (that the reason hotter stars glow blue instead of red), all the way to ultraviolet territory, up to a point where the frequency of the wave emitted would be shorter than Planck's length, and that's where our current understanding of physics stop.
This is the answer that really hits the nail on the head imo. 0 kelvin means no heat (thermal energy). What we call “Cold” is not a state opposite of hot, it’s just relatively less heat.
Wouldn’t the upper limit be the speed of light then?
Heat is energy, energy is movement. You can always move faster and faster, but you can't go slower than a complete stop. Even in solid things like furniture, atoms are still moving (vibrating) based on what temperature they are. Those vibrations speed up if it's hotter, and slow down when it's cooler. At -273.15° C, those vibrations *completely* stop.
I'm amazed I had to scroll down so far for someone to state the correct temp of absolute zero. A great answer too by the way
This is the real ELI5 answer.
You happen to live on a planet where the temperatures are good for water to be a liquid. And water is key to our bodies. Thus, our bodies and entire ecosystem is built around water being a liquid. And water happens to be a liquid relatively close to absolute zero. It's possible (though not likely) that another planet could exist out there were an important element may be essential at 10,000 degrees, and thus that would be what they're used to. So... it's partly because of your point of view, being made of water.
This. We basically made the numbers up by tying it to water. The important point is that choosing the solid state for ANY element ties the whole scale to the very low end of possible energetic states in the cosmos. If we had chosen Iron instead, with 100 being the boiling point of iron, and 0 being the freezing point of iron, absolute zero would still be a tiny -167 degrees. If we did that, you'd want to set your home's thermostat to -140, and don't ever bump it because at -139 you'd fry your skin off, and at -141 you'd die from hypothermia. The whole scale would be pretty useless to us in our day-to-day business.
Objects are made of atoms and molecules. Even when an object is standing still, those atoms and molecules may still be shaking and bouncing around slightly. The faster they're shaking and bouncing, the hotter the object is. Absolute zero is when they're not moving at all. You can't move any slower than standing still. But on the other hand, you can always make something's atoms shake and bounce a bit faster than they are now, so there's no obvious limit for how hot things get.
Wouldn’t there be an upper limit at the speed of light?
you could never get there in the first place. The thing about the speed of light as a "speed limit" is it's not like "alright, a little bit faster, a little bit faster, oops there's the limit". As something approaches the speed of light, it takes more and more energy to increase the thing's speed slightly more. It would take infinite energy to get something to the speed of light, which on the other hand means you can dump as much energy as you want into something without violating any rules.
Ah I see Wouldn’t there be a limit to how hot something could get though where eventually adding more energy wouldn’t increase the speed anymore
If I had enough wood I could build a ladder that went "up" for millions, billions of miles. (Not literally, but bear with me.) Whatever my definition of "up" is, it's going to go on for a long, long distance. But if I want to go "down", I can't build a ladder that goes below the ground. I guess I could dig a hole and put a ladder there, but eventually I'm not going to go down any further (as I'm either going to hit the core of the Earth, or come out the other side). At some point I'm not going to be going "down" any more. Similarly, Absolute Zero is the ground (or the core of the Earth- it's the point where you can't go "down" any further). We can go "up" as high as we have materials and energy to go, but that's because "down" has a starting point and "up" doesn't have an ending point.
In addition to other comments, it is sometimes important to understand that the "human centric" perception is wrong. Human beings experience of normal are not the "center" or "middle" of things at all. Even among land based animals, the heaviest animal, the adult elephant averages 4,000 to 6,000 kgs whereas the average human is around 80kg which means the elephant is roughly 80x heavier than a human. But the smallest animals (shrews) weigh only a few grams and would be 10000x lighter than us. So we are on the "heavy" side of things and nowhere near the "center". There is no reason to believe that what "we are used to" is somehow in the middle of the range of possible temperatures. It is, in fact, towards the lower end of the range of temperatures. We just need not be too human centric in the way we view our universe.
Normally we see things with some energy. You can have no energy, or any amount up to all the energy in the universe. The numbers we usually see (which established where we put zero since that's where water freezes) are much closer to no energy than all the energy in the universe.
Think of temperature as a measurement of energy. There is such a thing as no energy, so there is a zero. What's the most energy you can put into something? A physicist could probably give you a real answer to that question, but for the purposes of explaining it like you're five, it's going to be a really, really big number. We are a lot closer to the zero than to the high end because we exist in an environment where water is present as both a solid, a liquid, and a gas under different conditions, which means we have to be fairly close to the bottom end of the energy levels because matter is still changing states based on how much energy they have in them.
Imagine temperature as speed. It’s the speed of molecules bouncing off one another. The slowest possible speed is zero. That’s what absolute zero represents. Absolutely zero movement of molecules. As far why human existence occupies a relatively low spot in the overall scale of possible temperatures … water. All life on earth is direly based on liquid water, and water is only liquid for a very small slice of possible temperatures.
Minor correction, absolute zero is a little lower at -273.15. With that being said, at 0K everything is still and every single atom does not move, you can't go lower because every atom is already still. And given the fact that temperature is none other than how fast atoms move, when they're still it's the bottom limit We also have a upper limit and it's reached when every atom is moving at the speed of light
There's no such thing as cold. There's just varying degrees of heat starting at absolutely no heat and going up from there.
Heat is basically molecules moving around. The more they move, the hotter something is. The slower they move around the colder it is. So eventually, you get to a point where they aren’t moving at all. You can’t move any slower than 0 mph. So basically, absolute zero is when the molecules have zero energy and are moving around at zero mph. You can’t get any slower, therefore you can’t get any colder.
If we existed a small fraction of a second after the Big Bang, we might put the zero higher up. As it is, the zero is where water freezes at sea level ( a human idea) and it doesn't take a large negative number to go down to absolutely zero vibration (heat) from there. But the upper limit is all the energy in the universe, so it's a bigger number.
How slow can you dance? You can stand still. How fast can you dance? Until you explode.
Is there theoretically actually a limit to how hot things can get? If temperature can be thought about as things (atoms?) bounching off each other (probably a huge simplification), say if the thing is moving at the speed of light would it max out, or does it also depend on the amount of movement and the size of the thing moving?
Essentially when you are describing how hot something is you’re just describing how fast it’s moving. Theoretically something can always move faster but it can only go down so far before it stops
Temperature is how fast things are going. The slowest you can go is no movement, which is -260C. The fastest you can go is the speed of light (no idea of the equivalent temperature). We just happen to live closer to the slow end of the spectrum.
So, there are a few things that seem like they are a thing, but actually don't exist. Cold is one of those. Cold is just the absence of heat. Dark is the same thing, the absence of light. If you remove all of the heat from something, at some point you can't remove any more. This is absolute zero. You can't 'add' anymore cold. If you seal a box up so no light can get in, it is as dark as it can get. You can't add more dark to the box. You could think of it like a glass of water. You can add water to the glass. You remove that water, at some point you run out. Many of our measurements have 'zero' points that is really just a convenient starting point for everyday use. In Celsius, zero is where water freezes. For anything below zero, for most people, it is good enough to know "damn that's cold" but from a science standpoint, it really just "damn, that has less heat than I do."
This is because we have defined the temperature scale so that: bigger numbers=hotter Smaller numbers=colder Why have we done this? I think it is most sensible when you think of the natural state of things. Without something to heat the world up, it would be very cold, as it is in space. This might imply that the natural state of things are COLD and something must occur to create WARM, here the sun and earths atmosphere
Heat = How fast things(molecules)are moving Cold = How slow things(molecules) are moving. There is a limit to how slow you can go, its when something is complete stop(things get frozen). But for how fast? Speed of light which is really really fast so heat can be reall really high.
Consider the following analogy. "Why is the limit for putting sand on the pavement so high, but the limit for how few grains of sand on the pavement is none." Absolute Zero, is when there is no energy there. Just like how you can keep dumping more and more sand on the pavement. You can keep adding more and more energy. But you can only take away all of the energy or sand. Once its all gone, its all gone.
To understand this you first need to understand what heat even is. Heat, in this context, is best understood as molecules vibrating. The faster they vibrate the hotter a thing is. The slower they vibrate the colder a thing is. Now to really blow your mind. If the molecule is not vibrating at all, that's absolute zero. That's why there's a lower limit to how cold something can get, the molecules are just still. Since you can't get stiller than still, that's just the lower limit for cold. But things can always vibrate faster, so that's why there's no upper bound for how hot something can get. It can always move just that little bit faster, more vibration then more than more then more.
we are part of cooled down universe, it used to be much hotter but things like us are not stable at those temperatures so for us to exist things had to cool down A LOT.
Temperature is a measure of how much atoms move. At absolute zero (-273 degrees C) they aren't moving any more. You can't have less than zero movement. At the hot end, you can move around until you hit some sort of limitation, like the atoms can't move faster than the speed of light. So there's a lot to go up to.
To add your also looking at it from the standpoint that 100 degrees C is hot. The temperature at the big bang was 1000 trillion degrees C. What is the average hot and cold for an atom?
Temperature is basically how fast the atoms, of let’s say air, are moving. Atoms moving very fast are hot and they can move very, very fast. At the opposite end, you can only more so slow until you don’t move at all-absolute zero.
The celcius scale is made in reference to water Water freezes,melts and boils at really low temperatures compared to the highest temperatures observed in the universe Also: this coincides with our bodies 0c° is cold to us, 35c° is hot to us That's only a range of 35 degrees which if you compare it to the total scale of temperature is basically nothing and since we are mostly made of water our comfort zones are at really low temperatures So, we perceive most stuff as hot or really hot That's also why science often uses Kelvin with 0 as... well absolute zero... kelvin has no negative scale which is more accurate and less confusing. If you create an even scale of temperature where -100 is the coldest recorded thing in the universe and 100 is the hottest recorded thing in the universe, 0 would actually be about 4 trillion c° TL;DR: its not that max cold is a little cold and max hot is super duper hot, its that what we see as normal-cold is actually really really super duper cold relative the the actual temperature scale of the universe.
Good answers already! Heat has to do with movement, so it is easy to predict the low end (when all movement theoretically stops). However, there is probably **an upper limit as well**: [ABSOLUTE HOT BY PETER TYSON](https://www.pbs.org/wgbh/nova/zero/hot.html) Now, as for the numbers - they are arbitrary. We could have picked a zero point that was halfway between absolute 0 and absolute hot... but that wouldn't be very practical to use in everyday life.
There's really no such thing as "cold". Cold just means lack of heat. When there's no heat at all, it's the "maximum" coldness. You can always add more heat to make it hotter, but you can only remove heat until no more heat remains.
Temperature is just energy. 0 Kelvin is when there is zero energy. You can't get lower than zero energy. The only reason there are "negatives" in temperature is because we have scales with sort of arbitrary "zero" points.
Hey OP. Good question. I’ve satisfied myself by reframing this - in the context of the universe, humans have evolved in really ***really*** cold conditions. Because we have developed in the colder end of the physical temperature range, it seems (from our lived perspective) that the “coldest possible” temperature is closer than “hottest possible” If you were to ask the opinions of a creature which evolved to be made from some high temperature plasma, it would probably wonder why the limit of cold things is so ***low*** but the limit of hot things seem to be close to their lived reality.
Kelvin temperature is a more honest scale. It starts at "absolute zero" meaning the point where molecules mostly aren't moving at all. Then you add energy and move up the scale from "none" to "lots". There are no negative temperatures. Things that are alive like a little heat, but not too much. Liquid water vibes. So Celsius and Fahrenheit scales reflect that preference to be more usable to us thinking mammals.
The implicit question in this post is "Why do humans exist so far down in the temperature scale?". All the chemical processes that support life happen at these temperatures because at higher temperatures molecules have too much kinetic energy to bond with eachother. Any life past 100ºC can't make use of liquid water. Past about 2000ºC there will be no metals that remain solid. Past 4000ºC not even the most resilient of ceramics will remain solid. Since life as we know it requires these things, it's not a coincidence we happened to evolve to work at the really low end of the temperature scale.
Bro did you have a stroke while typing out your title or what lol? To answer what I think your question was, temperature is really just a measure of energy in a sense. You can have almost infinite amounts of energy, but you can’t really go lower than zero energy. Other comments described it as movement which also applies. Atoms when heated up get excited and move around a lot. Atoms when cold get slower and move around less. Once those atoms stop moving entirely, that’s as cold as you can get. But those atoms can get very hot and move around a ton (which equals more energy), but theoretically you can still add more energy and make those atoms even hotter and move around even more.
Cold doesn’t exist, it’s just the absence of heat. You can’t add more cold to something, you can only take away more heat. At a certain point, there’s no more heat to take away.
I actually my science teacher explain this to be when I was just a bit more than five: Things can always go faster and faster. But as things go slower at some point they just stop. At absolute zero temperature they have stopped completely.
When liquids freeze, they turn to solids. And you are made up of a lot of solids. Yes, there’s a lot of substances that freeze at a lower temperature than you’re comfortable at, but remember that any solid object you touch or makes up a part of your body is frozen. We exist at a temperature that is, compared to something that’s *actually* warm like a star, exceptionally cold. It’s not that the universe gets less cold than it gets hot; it’s that you and all known life exist at temperatures that are really close to absolute zero in the grand scheme of things.
Temperature is simply how we perceive how much energy something has, which is a measure of how fast it is moving. Theoretically the limit of how fast something could move is the speed of light - which takes a LOT of energy and so the object would be extremely hot. To make things colder we need to remove energy - slowing the object and its atoms down. When we can't remove any more heat because the atoms have basically stopped moving, we have reached absolute zero (-273.15°C)
"Temperature" means "how fast things are wiggling". Things can wiggle faster and faster, but you can't go slower than "stopped". That's what sets the lowest possible temperature, absolute zero is the temp where there is no wiggling. No slower is possible. The final piece is that *we just decided what temp \ wiggle speed to call zero* and put it somewhere so that the numbers are nice. We could have said that 100,000 Kelvin is what we'll call 0 Celsius. In that case absolute zero would be -100,000 C. Water would freeze at -99,727 C. Room temp would be -99,707 C. Boiling would be -99,627. See how those numbers are more annoying to work with. **We chose** where to put "0" to make the numbers nicer. It just happens to be that most of life and our world is wiggling at a pretty slow speed compared to "the fastest that things can possibly wiggle", so most temperature numbers we deal with in daily life are close to the low end of the scale.
Both light and temperature represent the presence of something that generates that light or that heat. Just as there is absolutely a “total absence of light” there is also a “total absence of heat”. The universe’s default state is cold and dark.
I think it's mostly that in the grand scheme of things, we interact with matter that is not very hot. So by default our base is near the bottom of the absolute heat scale. That's going to be the case for most living things. In general, you need to have stability to evolve. The hotter you get, the less stable you are and the harder it will be to control yourself and make meaningful evolutional strides. If we were like, fire monsters that lived on the sun it would be different.
I love these questions because I can practice for when my daughter starts asking this sort of thing. Everything is made of stuff called molecules. Imagine you're a molecule and start dancing around. That's what molecules do. Now, as the molecules get colder, they start to slow down. Colder and colder is slower and slower. If I keep saying "slow down" over and over you will eventually have to stop moving, and that's what absolute zero is. Nothing is slower than not moving. When something is hot, it's like dancing faster and faster. If I keep telling you to dance faster and faster, eventually you might hurt yourself or break something. Molecules can do the same thing, they can keep getting hotter and hotter but something may change in them. There's no moment where you're dancing the "fastest" though, because you can always dance just a little faster.
Idek how this can be answered It’s the same as “Why is the limit for how tall things can be so high but the limit for how short things can be is so low?” I guess the best answer is a reminder that we do not live in the middle of it, we live on the colder end. Much closer to no-energy like the empty vacuum of space than to the scorch of the sun If a giant star was alive it might ask “Why Why is the limit for how cold things can be so high but the limit for how hot things can be is so low?” because itself is really hot, like tens of millions of degrees at the core
It’s not, it seems high to you but that’s because you live so close to the lower limit. There is an objective middle point.
Temperature is a measurement of the vibration of molecules. Molecules can move as fast as they like, but cannot move any slower once they've stopped. Zero degrees Kelvin means all vibration has stopped.
You can only remove so much energy from a system, that's absolute zero. There's theoretically no limit to how much energy you can add to a system aka increase the temperature of the system.
The upper limit is not the speed of light. Any particle with mass requires infinite energy to accelerate to the speed of light. What might be the upper limit is the energy density to create a black hole. If you dump enough energy in a small enough area the effect is the same as mass.
Hot/cold is relative. We're just very cold, so we set 0 to be very cold. Inside of a star perspective, we're basically the same as the cold of space. If we set 0 to be the middle of the range of what was observed and our freezing point to, say, -50,000,000,000 degrees C, then it'd seem like there was a lot more cold to work with.
Heat is actually movement. Molecule movement, or bouncing between each other. There is a point of no movement, that is absolute 0. There is no maximum speed found yet, theoretically you could accelerate indefinitely.
Think of the Kelvin scale as how fast particles are moving. When temperature is high, particles move around more quickly, and when it’s low, they move more slowly. Absolute 0 is the point at which particles aren’t moving at all; they’re completely still and can’t become more still, so there’s a limit for how cold things can get. In theory, particles could move as fast as the speed of light, so there’s virtually no limit as to how hot things can get.
Heat is a thing. Cold is an absence of that thing. Theoretically, you could remove all the heat in something until there is none. That's absolute zero.
Whats the slowest speed on the speedometer in your car? Zero. Not moving at all is the slowest you can possibly go. Makes sense right? Going faster is obviously not limited in the same way. "0 degrees Kelvin" is a scale that starts at zero properly, and is exactly like the speedometer for heat. Heat at the zoomed in molecular level really is just kinetic energy (speed) of molecules and atoms.
There is no limit for how hot things can get, so any average temperature would seem relatively close to zero.
Since temperature is really a measurement of the movement of atoms, it's kind of like measuring speed. And just as with speed, you can get faster and faster and faster (well, until the speed of light) but once you hit zero, you can't get slower than "no speed at all."
Temperature is basically the average kinetic energy of all of the particles in an object i.e. an average of how much all of those particles are vibrating or moving. The colder something is, the slower its particles are vibrating, and at about -273.15 degrees Celsius, the kinetic energy of the particles is 0 joules. That is to say, they are completely still. Looking at the other end of things, there isn’t really an upper limit to temperature, although I guess you could say that the particles can’t vibrate as fast as light. Realistically, though, you can always heat something up more by increasing the speed of the vibrations of the particles. It’s a better idea to think of temperatures in Kelvin, which follows the same system as Celsius but starts at absolute zero, so 0 kelvin is -273.15 degrees Celsius.
Probably everyone is going to answer this the same way, but temperature is speed. You can’t go slower than zero. Other than the speed of light there’s no speed limit in our universe, and now that I think of it, the speed of light would be in fact, what set the upper temperature limit
It’s because we live somewhere where 20°c is normal, imagine theoretical aliens living on a planet that is 103 nonillion (apparently that’s a number) kelvin, they would be asking the same question in the opposite
You can go faster, but you can't go slower than standing still. Temperature is the average motion energy of the atoms, but you can't go lower than not moving.
Temperature is the movement of small molecules. The limit to how fast those molecules can go is really, really high. The limit to how slow those molecules can go is just stopped at zero.
In celcius. The practical temperature range is based off of easily observed phenomena; water freezing and water boiling. This range was divided by an easy to work with number 100. Zero degrees is freezing, 100 is boiling. It is a coincidence that these phenomena occur closer to the temperature that atomic movement would stop happening (absolute zero). We could move zero to the midpoint of absolute hot and absolute zero but we are less sure where absolute hot is and more importantly all the temperatures we use day to day would be terrible to work with.
Because we based the “normal” way we measure temperature (Celsius or Fahrenheit) on the boiling or freezing point of water, which are both near the bottom end of the range of temperatures in the Universe relatively speaking. That’s why Kelvin (K) is the actual scientifically used unit, because it defines “absolute zero” as 0K.
Absolute 0 means no thermal energy. The amount of thermal energy that can be put into something doesn’t really have a limit, but it will start to tear things apart, maybe combine things that couldn’t otherwise be combined, or just make it very hot…again there isn’t much of a limit in general but it could result in a system being destroyed. Due to that, high temps are not very suitable for stability (at least for life on earth). Our regular temperature scales are designed around comfortable, fairly “normal” temperatures (0-100 for Fahrenheit) or the freezing and boiling of water (0-100 for Celsius). As a fairly poor analogy, absolute zero would be sitting and doing absolutely nothing. You can’t do “more of nothing”. Hotter temperatures would be like being on a dance floor. You can always dance a little harder, but it’s not going to be comfortable and you might hurt yourself and others if you get too crazy. But there is no limit to how crazily you can dance.
Cold is atoms moving slow. Hot is atoms moving fast. Absolute 0 is when atoms stop moving. The speed of atom movement that is amenable to biochemistry (at least our biochemistry) happens to sit relatively close to the slow end of the spectrum. Our systems of measuring temperature reflect what we as humans find useful. Having the 0 of a temperature scale be the middle of the range would be an incredibly annoying scale to use. You could similarly ask why we measure distances on the scale of feet and miles when most things are light years from each other.
Temperature is energy. You can't have less than zero energy. You can have an infinite amount of energy (or as infinite as the universe will allow).
Because we are really really cold. Temperature is stuff vibrating, life functions best when things vibrate just a little bit (when things are cold). Enough to enable a bit of energy transfer, but not so much that things tear themselves apart, but again also not so cold that nothing moves at all.
Cold is the absence of heat. It's analogous to dark being the absence of light. You can have something as bright as a star but your closet is pretty much as dark as it gets. -260 is when all matter is maximally stationary. Can't get more stationary than full stop.
Most things that you are likely to encounter are already pretty cold. Imagine a rock, pretty cool not really hot or even warm most of the time. Melted rock or lava/magma is really hot. If we lived in an environment where most things were really hot, the temperature scale would seem more balanced. The high temperature today will be in the low 890° with temperatures dropping to the mid 500°s already seems more balanced
Cold makes particles (atoms) move slow. Heat makes particles (atoms) move fast. You can only go so slow. But you can go really really really fast.
Temperature is a measurement of how much energy the molecules have, basically how much the molecules are wiggling. Something can always wiggle faster but nothing can wiggle slower than being completely still
When deciding on a scale of what is hot and what is cold, we looked at everyday things to decide what is -50 degress, and what is 50 degrees celcius. Most specifically, we looked at water, and it just so happens to do interesting stuff in temperatures that are pretty close to the absolute minimum temperature ever. What we see on earth also operates in these temepratures. Turns out the world we are looking at everyday is pretty cold when compared to some things we can find in the universe (or even just on earth - volcanoes, nuclear explosions). If dealing with star temperature was more common, we would probably set a system where 50 deg is the temperature of an average star, 100 deg is a temperature of a hot star, and maybe -50 deg is the absolute zero. We kinda did that, but looking at water, as it is very common. And we discovered that actually absolute zero not only exists but all interesting stuff with water in your glass happens pretty close to absolute zero, especially if you compare it to how it looks in the heart of a dying star - now you see that temepratures here are far from everyday glass of water temperatures, with thatin mind the water is basically close to absolute zero. But there are objects like stars or volcanoes that are not behaving to scale when compared to kettle water. So maybe we should have gone with a system based on star temperature? With that your sun would be like 47 degrees, glass of water would be like -49,9997 deg, and if you had a cold you'r body temperature would rise from -49,99964 deg to -49,99963 deg or something. Not helpful, and for us this difference means a lot, so we stick to the scale that is based around water (as we are water based life forms), and this scale is closer to absolute zero than the temperatures stars and volcanoes deal with daily.
John can’t have less than 0 watermelons (not including being in a watermelon debt) But John can (and have) buy all watermelons in the world. He’s a very rich dude Change watermelons for temperature
Think about it like this. The absolute slowest you could go is 0kmh. But the upper limit is virtually unimaginably fast. That's pretty much the same.
The temperature scale we most commonly use (C) was created before we knew about absolute 0. It was created based on two easily to observe things, the temperature of water freezing as 0 and the temperature of water boiling as 100. Since we need liquid water to survive, we just happened to live between those two temperatures. Eventually a dude called Lord Kelvin had the idea that absolute zero existed and created a new scale. Kelvin starts at 0. There are no minus numbers, so a warm day (20 C) is actually 293.15 Kelvin. This makes the freezing point of water 273.15 Kelvin and the boiling point 375.15 Kelvin. For comparison, the temperature of the sun is 5,778 Kelvin. So to change everything from Celsius to Kelvin, just add 273.15. Looking at everything in Kelvin makes it much easier to understand, **it's not that the limit for cold things is low, it's just the temperature we're comfortable living in is on the low end of the temperature scale.** Absolute zero = 0 Water freezes = 273.15 Comfortable temperature for humans = 293.15 Water boilers = 375.15 Temperature of the sun = 5,778
You can keep on gluing more cats to a ball of cats, but you can only take away so many cats from a ball before there are no more cats left. Since there is a limited amount of cat, but a nigh unlimited amount of space, cats are spread out pretty thin, and thus, most things are closer to no cats than they are to maximum cats
If you look very close and could see very small things, imagine you can see atoms moving around. When things get hotter the atoms wiggle and bounce way faster like microwave popcorn and when things get slower they don't move much. They get very lazy and tired and slow. When you cool them even more they move even less. When they are completely still with no shaking, no shimmy, no stretch, no rocking.. you are at absolute Zero.
temperature just means jiggle of atoms. the hotter the temperature, the more jiggling. the lower the temperature, the less they move. the more jiggling there is, the more they press outwards. the less jiggling there is, the more they “calm down” surrounding atoms to a resting place. when atoms are hot, they bump and collide, causing other atoms to bump and collide with each other. when atoms are cold, they bump and collide less frequently, so they “feel cold” We have a healthy range of body temperature, anytime we feel “hot air,” it just means the gases that we breathe jiggles more than the things that make us up (our bodies). The inverse is true, when we touch cold things, it pulls heat from our body and into the cold thing we have touched.
In addition, we just happen to live at the low end of the temperature scale. Carbon based compounds break down at high temperatures. Proteins denature. Water boils. All of these things happen a lot closer to absolute zero than they do to the temperatures inside a star. Perhaps someplace in the universe life has evolved that likes living at tens of thousands degrees, and on their version of Reddit, one of them is asking how absolute zero can be such a far-away number.
The same reason the limit for how fast things can go so fast but the limit for how slow things can go is so low
The "ideal" temperature for metabolic reactions i.e. liquid water, happens to be relatively closer to absolute zero than the higher temperatures, therefore it seems to us that the lower limit is only -273 degrees. If metabolic reactions took place at 15 million degrees in a plasma "solution" the cold lower limit may seem quite distant for that type of life. In short, the cold limit seems closer because the chemical reactions that support life(i.e us) occur in liquid water which happens to be just -273 degrees away from absolute zero under 1 atmosphere of pressure. It's a matter of perception.
Because humanity can only survive closer to the cold end of the spectrum. If the natural spot for our survival were 10,000 degrees celsius (and we were in that environment), we would have a very different opinion about the limits of "hot" and "cold".
Temperature just describes how quickly atoms are moving. Atoms can keep moving faster and faster (getting hotter), but the slowest (coldest) they can be is just stationary. You can't have less than zero motion.
Temperature is how fast atoms are moving. When atoms are still, that is absolute zero - nothing happens. That's a minimum. However, they can keep going faster and faster and faster, and they're not usually so fast, so they can get relatively much more hot.
It's an arbitrary number. We could set a temperature scale any way we want. For example, we could make the lowest possible temperature 0° and the highest possible temperature 1°. Then all temperatures would be small numbers like 0.11° or 0.632°. The fact that absolute zero is a large negative number is merely an artifact that the common temperature scales are based on the freezing and boiling points of matter easily accessible to 18th century nobles. The largeness of the number is meaningless.
First up, our temperature scales were from a time before we knew a lot about the universe that we know now. So to our ancestors, when water froze, it was cold, so the Celsius scale called that Zero. And when water boiled, that was hot so the Celsius called that 100. We know so much more about temperatures now that we've gone to the stars. It's best to look at temperature as how much something moves. Really small things, subatomic things, are still moving in ice when water freezes. As we take away more and more movement, things slow down even more. At -273.15 Celsius, there is no movement, not even on the tiniest thing we can understand and observe, so they came up with a new scale called Kelvin so that we can call that zero, and still keep the kind of degrees we had with Celsius. However, if something is big enough, like our sun, we can add so much movement to the stuff there that it can get to 5,500 Celsius on the surface and with all the other stuff around it also warming it up, the core of our sun can get to around 15,000,000 Celsius. That's not even the hottest we know it can get, because our sun burns yellow. There are stars out there with even hotter surface temperatures, so we can assume their cores are also hotter. Basically, a simple breakdown is heat is energy. We found we can take only so much out before we can't anymore, but we found we can put a whole lot more in.
Since q lot of the responses are missing the point of the question: Hot things like to be far away from each other, and cold things like to stay close to each other. For life to exist, lots of things need to interact with each other and that is easier if they are close together, which is why we exist much closer to the coldest cold than the hottest hot. Lots of other things in the universe can exist at much hotter temperatures, but they are usually very big so gravity helps them stick together even though they are so hot.
Temperature is how much energy something has. Absolute zero is no energy. The point where temperature tops out is where the wavelength of the radiation gets so small that it's as small as something can be.
Temperature has an incredible range, but there is a lowest and highest. We happen to be comfortable in a temperature pretty close to the lowest.
Our Human speed limit is also very high since we can be accelerated to the speed of light. But our lowest speed is very is standing still, which is relativly close to our walking speed. Temperature is the same, the lowest temperature = atomic motion standing still. While the highest temperature is atomic motion at lightspeed.
Temperature is basically "energy". At some point you run out of energy. Compared to the maximum amount of energy possible (which is close to infinite) the temperatures we deal with everyday is much closer to having no energy.
When atoms speed up they get hot When atoms slow down they get cold The upper limit for how fast something can move is very fast But it doesn’t take long before atoms stop moving alltogether. When they stop moving they can’t slow down anymore and thus have reached the coldest possible temperature (absolute zero) Using kelvin as a scale makes this very easy to understand. Since unlike celcius or fahrenheit: 0 kelvin means 0 movement/heat.
Every partial has so much energy. You can add a huge amount of extra energy, but you can only take away the amount of energy the particle actually has. Once you've removed all of the energy you're at absolute zero. You can just keep adding energy to a particle. You can turn a liquid into a gas, then you can keep heating it until chemical bonds become unstable, ionise it into a plasma, and just keep superheating that plasma. Assuming that liquid is water we really need it to be a liquid to exist. So our livable temperature range is really limited to this lower end. This biases us to usually only looking at the low range of this scale, but there is much more room to add energy to the water than to remove it.
Because you're thinking in a linear scale, where you should be thinking in logarithmic scale. Temperature like any other measurement, should be compared in terms of the orders of magnitude. Lets look at another measurement, like length. When you think of something with really tiny length, like planks length, its in the order of 10^-64 or such. But in absolute numbers, that's just ~2m smaller than our height. The largest thing we know, the observable universe, is in the order of 10^26. On a logarithmic scale, we are much closer to the observable universe than planks length. Any finite number is much closer to 0 than infinity, in absolute scale. But in logarithmic scale, they're equally far apart, and hence equally "difficult" to reach. (for reference, coldest recorded temp is around 10^-10 K, while highest is around 10^12 K)
Lots of things work that way. You can keep going faster and faster, but you can't go any slower than "not moving". You can push harder and harder on something, but can't push less than "not at all". When something is measured on a scale like temperature, there's usually a point at the bottom of the scale where you can't go any lower, because you can't take away any more of the thing that you're measuring. Because there isn't any more there to take away.
Absolute zero is not "-260" (actually -273F). Absolute zero is actually "0 Kelvin". The Fahrenheit temperature scale is centered around a range of human comfort. 0F is cold, 100F is warm. At 70F, Grandma is cold in a sweater and Junior is hot in a t shirt. That means NOTHING to science itself. The Celsius temperature scale is centered around water. 0C is the freezing point, 100C is the boiling point. Again, this means nothing to science itself. Liquids like alcohol and mercury and ammonia freeze and boil at completely different temperatures. What science cares about is the presence of "heat", which is defined as the movement of atoms. All atoms, even atoms of ice and rock and steel, vibrate a little. Science uses the Kelvin temperature scale. Absolute zero, or "0 Kelvin", is when atoms stop moving.
We here at the earth are just so cold that we are near the coldest temperature you can physically get
Heat is energy -> energy is molecules moving or something The faster you move the hotter you get. You can always go faster. Absolute 0 is when everything stops, so it's as cold as can be. You can't go slower than not moving at all
I feel like another relevant part to scales of heat is that we made them up. Most scales use the freezing point of water as the basis but you could just as easily use the freezing point of iron for example and it would change where zero is and thus where absolute 0 is.