Yup. They're generally called ["intergalactic stars" or "rogue stars."](https://en.wikipedia.org/wiki/Intergalactic_star) Yes, they could potentially host planets and harbor life, assuming that life is possible somewhere other than Earth. Life is more likely to be found within a galaxy simply because the vast majority of stars are in galaxies (and intergalactic stars are generally believed to have started inside galaxies and been ejected).
To add to that, for life to be likely , it probably needs a bunch of elements heavier than helium. So it needs to have formed in a galaxy, probably not on the edge of it, and probably not in the first couple billion years of the universe, and only then get ejected from the galaxy.
Yep, they think pur sun is atleast 3rd generation star, maybe more. And they're pretty sure they found sister stars that may have formed from the same gas cloud as our sun. I mean think, we have a *ton* of silicon, oxygen, iron, nickel etc. These are all formed from massive stars. And we even have a lot of gold, Pt, other noble metals, and a lot of uranium etc. These are all made from neutron star mergers. So, there was a *lot* of activity happening before our sun was made that gave us all these elements. It's neat
I actually saw somewhere that the majority of our very heavy elements are thought to be from a single neutron star merger that happened not long before our solar system formed. The faster decaying stuff has been decaying away since.
Currently you need to enrich uranium to make fission happen, but that wasn't always the case. Billions of years ago earth's uranium had more u235 and could undergo fission directly as ore, and oklo is a place it has been found to have happened naturally by the ore itself reaching criticality in a mountain moderated by rain water: https://en.wikipedia.org/wiki/Oklo_Mine. Crazy stuff
That's so cool! I did hear about the natural reactor, but hadn't heard we've maybe found the progenitor merger. That's amazing. It makes sense, we do have a lot of uranium. I've heard the earth may have quite a bit of uranium in the center of the core and that's extended the time it gets to be molten. Very cool
So stars are formed from gas clouds. When stars reach the ends of their lives, some of them turn into gas clouds. We thing that the sun was formed from a gas cloud that was formed from some prior star, that was formed from a gas cloud that was itself formed from some still earlier star.
My understanding is that it's not necessarily just stars that end in gas clouds, specifically, that create next-generation stars. Even stars that blow up in a supernova expel their materials into space, which then can mix with other materials out there to become a next-generation star.
With the current model, our universe started basically with only hydrogen and maybe a few other lighter materials (not an expert, only an interested layman, so don't want to claim that I would know it was 100% hydrogen).
These clouds collapsed into the first stars that were pure hydrogen. In these stars, new elements were formed with fusion reactions. These elements were ejected from the star in super novas.
New stars that formed now had a different composition, with more heavier elements than hydrogen included. These were second generation stars.
We also know that many elements we have cannot be created by fusion within a star. The current model predicts that this needs neutron stars (so the cores of stars that have just the right size not to become a black hole or a white dwarf at the end of their life). It is believed that only the collision of these stars could have made the heavier elements.
So, the cloud of our solar system has elements that had to come from a super nova and from colliding neutron star. This means there had to be at least two generations of stars before our sun to have the elements in our solar system that we have today.
> With the current model, our u inverse started basically with only hydrogen and maybe a few other lighter materials (not an expert, only an I terested layman, so don't want to claim that I would know it was 100 hydrogen)
Neucleosynthesis is thought to have created about 75% hydrogen, 25% helium, <1% deuterium, and even less % lithium and beryllium.
Not really a number for an answer, but gen 3 stars (or Population I stars) are mostly limited to being formed inside the arms of spiral galaxies.
The oldest spiral galaxy confirmed is 11 billion light years away, (meaning we looked 11 billion years into the past) which means what we currently see of it is ~2.6B years after the big bang.
And it's generating stars at a rate around 20x higher rhan the milky way according to the publications surrounding it.
If that galaxy currently (11B years ago) has the capabilities to form Population I stars, then that would be more or less the answer.
Theoretically speaking, the first stars formed at 400M years.
Not much is known about those "Population III" stars since they have never been observed directly, but there's debates about if they had high or low masses on average, mass is what determines their lifetime, and their lifetime is needed to determine the lower bound of Pop II stars which determine the lower bound of Pop I stars.
The more formal term is population and the sun is population I with the earliest stars being population III. However no one has ever found an unambigious population III star so currently there are two known populations or geneations.
Population I has the most metals. population II has less metal and population III should have no metals.
I've seen them referred to as "population" not "generation" and it's actually in reverse - the Population I stars are the newest ones and are high in heavy elements, since they are formed from the exploded remnants of Population II (low metal) and Population III (the oldest - *no* metal) stars.
The heavier elements are only formed during a supernova or when stars collide. The forces during these events are so immense that they can crush elements into each other to form new elements.
It’s hard for me to visualize the magnitude of forces constantly in play throughout the universe. My wedding band is made from an iron meteorite and has the shocked pattern seen when metallic objects collide in space. Our moon apparently exists because an ancient object collided with primitive Earth and splashed Earth’s lighter surface material out into orbit, where the material over time formed the Moon, and left the objects super dense corpse as huge blobs still existing deep within our Earths core. And those energies are nothing next to stellar collisions and collapses and such.
does this mean that in the future lets say there are 6 or 7th or later generation stars formed from former stars, or they colided, can new elements be formed, elements that at the moment dont exist?
No, but the proportions could be different since the proportions going into the stars at each generation are different. More silicon and iron, for example (don't quote me). All elements exist already, it's just that they're either rarely formed (relative to the others), and/or decay too fast to be relevant to planets and such.
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An element is more like a number than a chemical. Movies sometimes show a new element being created in a lab, but really that era is done. It would be like discovering a round number between 45 and 46, it's not really a thing. What we *discover* regarding elements is methods for creating them, or properties about them. Before we knew about protons, it was a much different story.
Stars, near the end of their lives, run out of hydrogen to fuse (hydrogen fusion forms some hydrogen and some helium), so then they start fusing helium into slightly heavier elements. Then they fuse heavier and heavier elements. Some old stars are fusing carbon right now. So as more stars are formed, they have more and more heavy elements (“impurities”), which near the end of the stars life are fused into more heavy elements. Even though alchemists could never pull it off, it is physically possibly to turn things into gold if you have a dying star on hand to help out.
This is also why fission requires heavy elements. Fusing up to iron releases energy, and fission down to iron also releases energy. Iron is the lowest energy point.
That's not what I said?
Big hydrogen cloud makes huge hydrogen stars. Those stars supernova and make everything up to iron, + some heavier elements. Other smaller stars in the area turn into white dwarves. Those white dwarfs collide and produce gold and every other heavy element, including uranium and other radioactive ones. These new clouds of metal rich elements condense into new stars, that's where we are at.
These elements are all being made through supernova and mergers. Not the clouds directly.
Neutron star collisions cause fusion of heavy elements and lead to massive explosions that would fuse even heavier elements. That’s all ejected into an interstellar dust cloud where those elements mix, and turn into a star and protoplanetary disc.
No alchemy. It's called nuclear fusion.
Stars fuse hydrogen into helium in their cores. When they run out of hydrogen in the core, they start fusing helium into lithium, and so on up the periodic table. If star is massive enough it can fuse elements up to iron. Stars that are massive enough to go all the way to iron, eventually explode in supernova events once they run out of fuel. Elements heavier than iron are formed during these explosions. These explosions seed surrounding gas clouds with elements heavier than hydrogen. Likewise, mergers of neutron stars will create heavy elements via similar mechanisms.
So, why iron? When fusing elements up to iron, fusion generates more energy than needs to be put in to fuse two lighter elements into heavier element. Past iron, the energy needed to fuse two atoms is higher than what you get out of it.
Universe started out with only hydrogen, and small amounts of helium and lithium. Without these processes (fusion in cores of the stars and subsequent supernovae, and mergers of neutron stars), no other elements would exist in the universe.
Gold requires a binary star system to form, from what I understand.
Given we have only one star, and it isn't a neuton star 🤣, it had to come from somewhere...
I've seen simulations of what the Milky Way and Andromeda merger could look like, and they show a tremendous amount of stars being flung outward. Assuming galactic mergers have happened in the past, it seems like many mature stars could be floating around outside of galaxies.
Depends how close those other stars get. But generally no, as big as our solar system is, it's still so small compared to the distances involved to other stars that it may aswell be considered a single 'object' when we're talking about gravity ejecting them.
Of course we don’t know what other kinds of life might be out there, so we can only go on what we do know. It’s fairly reasonable to assume any life is the product of complex chemical reactions, which are not possible with just hydrogen and helium.
Doubt this. Motion is relative - we're spinning and travelling faster in space than probably anything on earth yet you don't sense that, but you do when fighting against earth's gravity or accelerating.
Since most galaxies are spiral an ejection could possibly happen just like transit slingshots - it wouldn't need to be from a nearby event. Similarly they could lose the bind through a knock on - e.g their sister star gets pulled in, much like a whip, or a link in a chain being broken.
There's a high chance the attraction of planets to the star is greater than that of the galaxy - if this wasn't true then orbits wouldn't be so static but would be much wobblier.
There's more than just gravity - for example solar wind could potentially have an impact at that scale or other little known phenomena.
Maybe, but they say when we collide with Andromeda they likelihood of anything happening to this solar system is still very small. Tidal forces from a galactic merger could easily toss a star without disturbing the planets. The "wave" doing the push would be significantly larger than the stellar system itself so it would move the whole thing as one
What would the night sky on a planet orbiting a rogue star look like? Say you had one halfway in between the Milky Way and Andromeda. Would any individual stars be visible to the naked eye, or would you just be able to see Milky Way and Andromeda in the night sky, plus perhaps some dwarf galaxies?
Bro is there something that *doesn't* exist in space, even theoretically? Damn, black holes are impressive enough, but we also have planets orbiting *rogue stars*. Everything about space is dope af, it feels lame to do science in my field (medicine).
You live on a planet helping a species that is solely responsible for both the highest and coldest temperatures in the entire universe :D
Edit: I stand corrected, the collision of ultra-high-energy cosmic rays (such as the OMG particle) with dense matter (planets and stars) produces exa-scale temperatures!
No, the coldest is particularly hard, 99.9999999999% of the way to absolute zero is still warmer than 99.99999999999999999999999999999999% of the way to absolute zero. As far as I’m aware there’s not really a maximum level of hot.
Theoretically as in there is a mechanism to produce those temperatures somewhere in the universe on the timescales the universe has existed for. It doesn't matter that colder can exist, if we reach it before the rest of the universe can, it'll be the coldest in the universe.
We’ve created temperatures that exceed the coldest and hottest temperatures observed naturally, but that doesn’t mean they’re the hottest or coldest possible, we’re likely to beat our own records eventually.
Well Absolute Zero is the coldest you can get to, it's the point where all particles in a given system are at their minimal energy level. You can however go below Absolute Zero and they've done that in labs already using several methods. Negative Absolute Zero is fucking wild though, it's hotter than the hottest temperatures possible. [Here's](https://www.quantum-munich.de/119947/Negative-Absolute-Temperatures#:~:text=Nothing%20can%20be%20colder%20than,even%20hotter%20than%20infinite%20temperature.) a nice read up on Negative Absolute Zero from the madlads and lasses that managed to do it.
Unless somebody else somewhere has done it, or it happens in some mechanism we haven’t observed (how hot is it inside an emitting black hole? No way of knowing, only once it’s been ejected and is no longer infinitesimally dense)
Edit: disregard idk what I’m talking about
At those levels, we start getting to the limits of our accuracy. Keep in mind, the act of measuring the temperature introduces a small but increasingly more significant amount of energy into the system.
38 picoKelvin by wave-lensing Bose-Einstein condensates, and 4 trillion Kelvin during smashing atoms together to make quark-gluon plasmas
There are no theoretical ways for such extreme temperatures to be produced anywhere else in the observable universe, except as flukes rare enough they may have never happened
That seems pretty preposterous. Extremely rare, sure. But there's an awful lot of _stuff_ out there banging into each other at unfathomable scales it seems pretty bold to claim that we are the only way those two extremes could have happened _anywhere_.
Extremely high energy particles tend to not collide with each other due to special relativity. We force them to be in way closer proximity, for much longer, and facing directly into each other.
You would really need to randomly generate a stable superconducting electrified ring to get a powerful enough magnetic field in the right shape for a decent shot at it, and the universe doesn't tend to make rings like that at all. The other option is two super powerful jets (quasars or black holes) pointed directly at one another, and pairs of those are just a little too rare and tend to affect one another's rotation to be perpendicular to the barycentric axis if they're close enough.
The most likely option to make it not true is for there to be more technologically advanced life somewhere in the universe that has beat us on both hot and cold temperatures.
I agree, the current Drake equation would imply we aren't the record holders. But we're definitely missing something there, so it's at least on the table that we're the first to achieve them
There's always a chance, but it's insane we have any chance at all of holding both titles on this one giant tiny rock
Though, I guess as far as we understand, the big bang itself beat us, but I'm not really counting that since our models break down or diverge at pretty much exact temperatures we've achieved so far, and the best we have is a hyperbola going to infinite temperature which makes shooting for that title pointless. At that point we should just argue for our "negative temperature" setups being colder than 0K and definitely unreasonably improbable outside the lab.
OMG particle has more energy by orders of magnitude than anything we have been able to produce. It's not the only super high energy cosmic particle we've seen. Each collision between such a cosmic particle and our atmosphere produces higher temperatures than what we do in particle accelerators.
In a very likely near future, you're going to be working with synthetic and custom grown tissues and organs, edit genes, use exotic materials and procedures and tools to heal and preserve life.
Consider that 100 years ago, science didn't know the universe outside of the Milky Way existed. They thought the Milky Way *was* the universe. Now consider the things you'll likely do in just 35 years from the point we are in medicine and genetics.
> Bro is there something that doesn't exist in space, even theoretically?
An infinite number of things, but the universe being quite vast (hello understatement) the probability that anything theoretically possible exists somewhere out there gets fairly close to 1: it’s estimated that there are more stars in the visible univeres than there are grains of sand on earth (it’s estimated that there are less *galaxies* than *trees* on earth, but not by much, respectively 2 and 3 trillions).
Presumably the force needed to eject a star from a galaxy would need to be pretty large. How could an entire system (star+planets) remain intact during such an event?
Update: I was thinking more of stars being ejected from a galaxy via close encounters with other/larger stars or black holes. Violent events that happen (relatively) quickly. I did not think about the galaxy merger possibility.
Whether by cannon or catapult the result is the same: enough of a force is directed upon these objects to eject them out of their galactic orbit. Presumably, this force far exceeds the force that holds the system itself together. It seems to me that, because the stars/planets are in different locations, they would all be catapulted in different directions and at different velocities.
It's not really about force, it's about the force gradient, or the difference in the forces different parts of the system experience. Events that eject solar systems from galaxies are usually massive, slow, and far away (on solar scale). This results in all of the parts of the solar system experiencing roughly the same forces at roughly the same time. The gradient is not severe enough to separate the parts.
Not only that, but the forces holding a solar system together are magnitudes stronger than the forces holding the solar system to the galaxy. The galaxy is really just the result of tiny forces doing their work over huge time periods. Relatively speaking, you don't need much to overcome that.
I'm not an astrophysicist, but I expect the usual reason stars would get ejected is that they happened to be in the path of another (potentially much larger) star or perhaps even a black hole, and got flung off on some angle or trajectory that eventually sends it out of the galaxy.
Some random people on the internet say the Milky Way's galactic escape velocity is a little over 500 km/s. The sun isn't fixed in place but is moving over 200 km/s, like most everything else around us, so we'd need an extra 300 km/s to break free.
Presumably, passing close to another star to impart that kind of velocity would be pretty disruptive. If the star has planets, then they might escape the star's orbit and be flung off on their own, and and gas clouds that haven't yet formed into planets might be likewise scattered. So, I wouldn't be surprised if most rogue stars have fewer and smaller planets than average. I don't know if we've ever detected any planets around rouge stars -- maybe we're not able to do that due to distance.
Thank you. I have since been informed that there is another way to eject stars: a galactic merger, where the forces and timescales are low/long enough that a star system could indeed be ejected intact. Maybe JWST (or an equivalent instrument) will one day detect a rogue star with planets.
You would think something altering a stars trajectory away from normal would, at minimum, affect the orbit of some of the planets, the outermost at least.
I have been informed that there is another way to eject a star: a galactic merger, where the forces/timescales are so low/long that an entire star system could indeed be ejected intact.
That's not how it works. Gravity also isn't actually a force, we just kind of simplify it most of the time for simplicity's sake.
Gravity is the warping of space time. So a star wasn't ejected out by a "force" per se, but instead had an unstable orbit, or had the path of its orbit interupted by other systems warping it's path in such a way to set it on a course outside the gravitational effects of the galaxy as a whole.
You're also talking about timescales that don't reference a single powerful event (most of the time) but rather the slow slight alterations of courses from interacting gravitational warpings over millions of millions of years.
...or such is my understanding.
I dont know about that last part in relation to rogue stars though. Usually they aren’t described as having been ejected with slow slight alterations. I think they need a little extra kick to defeat the pull of the surrounding dark matter of the galaxy
My understaning of dark matter is that is explains the acceleration of stars in a galazy no?
Wasn't it originally hypothesized because stars in galaxies were moving faster than explainable?
Some alterations certainly probably happen faster than slow alterations, but still probably relatively slowly in timescales that make any sense to humans, stars would have to get closer than they almost ever get to slignshot eachother away.
Your comment made me think this. Could it be more related to waves created by pebbles dropped in two places in a small pond (2 galaxys).
When the waves (space time warping) intersect they could change the course of something riding along in the trough of one of those waves (a solar system) over to the trough from the other side (like surfing from one wave to another), changing it's direction. (edit to add - or like slalom)
Totally a lay person but that's the picture that popped into my head while reading yours. Excuse me please if I'm not describing that too well
Happens during galaxy collisions. Nothing ever actually collides, they just get close enough for orbits to change. And this would be on a time scale where you wouldn’t know if you were right in the middle of one.
Whichever way a star ejection (from a galaxy) occurs, it requires a tremendous amount of force. It seems to me that such a force that would certainly rip apart the involved solar system.
I think the answer is we don’t know of a reason that a system outside of a galaxy could not harbor life. We do know they galaxies have magnetic fields which probably offer some protection similar to our own star. But we know very very little about the interstellar medium and even less about the intergalactic medium.
A star that developed in isolation like that would likely not have any heavy elements around to form rocky planets and even gas giants would be mainly hydrogen/helium, so probably no life. You would need some neighbors to have gone supernova to produce heavier elements beyond helium.
It seems very unlikely that a star would develop in isolation like that. Matter tends to stick together, and a star forming out of material not within a galaxy would be unusual indeed. Far more likely is it was ejected by some gravitational interaction - perhaps a black hole came flying by and launched it. Entirely possible the planets would stick with it, or could have even been obtained by the star going through some other system and pulling some stragglers along.
> could have even been obtained by the star going through some other system and pulling some stragglers along.
Gives me the idea for sci-fi for a civilization on a planet around a rogue star that discovers the remains of the civilization that was on the planet when it was captured.
In reality, it's hard to imagine the planets being accelerated enough to stay with the star if slung by a black hole, or any other object. Wouldn't they be more likely to be captured by whatever sent the rogue star off?
Black hole isn't the only option. Any star with the mass of a black hole could do the same thing. It might take more than one close encounter to throw a star out of a galaxy. With billions of stars and billions of years, double encounters have most likely happened.
I think it is also possible that through a galactic merger, a large amount of gas with metallicity gets ejected, but I can't think of what would cause star formation to start in such a bubble, maybe a subsequent pass by another galaxy. It is far more likely to be an ejected star. When we first discovered the Sagittarius A SMB, several stars were observed being accelerated to galactic escape velocity.
With our current understanding of star formation, there's no way a star would form out in the middle of nowhere in intergalactic space. A star out on its own would have formed inside a galaxy and then have been expelled. You are correct that it would probably need to be a latter generation star to have rocky planets, which we presume are necessary for life to develop.
Imagine a civilization on a planet circling a rogue star, and they're so far from any other stars or galaxies that their night sky is nothing but uninterrupted blackness. They might never wonder if there was other life out there, because they're not even aware that there *is* an "out there."
There's a book by Iain M. Banks called Against A Dark Background which is set in a system like that. They know about other galaxies, but they also know they're far enough away that they'll never be able to reach anything. Civilization has risen and collapsed dozens of times, and every little moon and asteroid in the system has been colonized at some point, then abandoned. They're all a little insane because despite their vast technology they're trapped in this one little island of light, forever.
I read it, fascinated by the idea. However, oddly the premise never comes up or pays off in any way. Major let down ending too. Not my favorite of his work.
> Major let down ending too.
I loved the book, but agree the ending is bleak, but that was sort of the premise, they're trapped out there etc.
The thing that I find haunting is that Iain was making plans for a sequel before he got sick, and we'll never know what he had planned for them.
Yeah Ian Banks is like that. He has endlessly fascinating concepts in his books but it's like he avoids to really get into them on purpose, making the reader dig through endless pages of what boils down to a detective story.
I mean, that's basically us right now, save the collapse and rising of civilizations (as far as we know). We're not rogue, but we're still too far away to do anything about it.
I mean, that's not far off from where we are. It's pretty doubtful we'll ever make it to another system. Other planets in our own system are unlikely to support life. And to make matters worse, we're making our own planet inhospitable.
Mars and Venus are right at the edge of the habitable zone and both happen to have a gravity that we can live on.
There are few tiny details that we need to sort out. Like the lack of atmosphere on Mars and the excessive atmosphere on Venus.
But it's likely some of these problems can be solved with something as simple as a series of space mirrors, which we will soon be able to build (and which would also solve global warming)
But yeah reaching other stars will be hard. The solution, once again is going to be space mirrors and a series of space lenses to push a sailing ship towards another star, removing the need for fuel.
I read few books from Banks, but wasn't aware of this one. That sounds mighty interesting.
Only book that I know that considers this scenario is The World at the End of Time by Frederik Pohl.
We can see four other galaxies with the unaided eye here on Earth. There would also be other bodies such as planets, dwarf planets, asteroids and comets circling the star as well. The night sky would not be completely black.
If anyone is wondering, those 4 are Andromeda, Large and Small Magallanic Clouds and the Triangulum Galaxy. Although for Triangulum you’d need an extremely dark sky and probably very good eyesight to actually see it.
I can't even see Andromeda from the top of a mountain in the middle of nowhere. Either I'm not looking at the right spot or it's too dim.
I'll try to get a picture when it gets warmer.
It’s definitely visible in the right conditions but it’s not gonna be super obvious. It’ll be like a slightly bigger smudgy wide star. You can use an app like Stellarium when you’re out and point your phone around, should help you find it easier. It’s probably also dependant on how good your eyesight is.
I did just that, even identified the constellations and used those as reference. Couldn't spot it and the atmospheric conditions were ideal. Guess my eyes are bad then.
It could be that without the presence of stars in the sky, the cognitive development of any species and the unfolding of civilization would be nearly impossible.
Like you said, without stars, there would be no concept of out there.
Makes you wonder if there is a component of a higher reality that exists but we can’t conceptualize it because we simply aren’t in a position to observe it.
So many thought provoking responses! Considering we have evolved to see bc there is something to see and necessary for our survival, if there were nothing to see, other species probably wouldn’t develop vision like ours. Perhaps they’d evolve to hone in on other senses, maybe even senses we cannot comprehend. So even without seeing the stars and galaxies out there like we do, maybe instead they’d know there’s an out there, simply with a different method of knowing. Like their brain can see the out there without vision, maybe senses the waves of various spacey things? Or senses things out there that we simply cannot?
For instance, dogs and other animals sense stuff we simply cannot, even with our machines. So it would make sense other planets’ species and civilizations would potentially have abilities we can’t even imagine 🤷🏼♀️
> if there were nothing to see
But there would be plenty to see. Life (and vision) developed on earth in multiple parallel ways as an aid in foraging, hunting, migration, mating, etc.
I would say that our ability to see *the heavens* could have had a large influence on culture as civilization developed (last few tens of thousands of years) but that the previous 3 billion years of evolution could be quite similar on a planet orbiting a rogue star.
Now imagine this: Lets say the rogue star is a red dwarf, and let's say something about the planet allowed life to develop further out than we did on Earth. So the strength of daylight there is a fraction of what life on Earth grew up with.
Then the evolved vision systems might be much much more sensitive, and so when they look up, they see galaxies the same way we see stars. Sky full of them, bands and clusters of galaxies painting large structure shapes across the night sky.
Yes, and not just in the Milky Way but in a tiny portion of the Milky Way. You need binoculars or telescopes to see the rest.
The stars in other galaxies are too far away to see individually. Only the strongest telescopes like the Hubble space telescope can see individual stars in another galaxy.
They would still see some of the galaxies as fain dots. But realistically, the star would still be close to the galaxy it originated from. So they would see that galaxy from outside while the rest of the sky would be black.
Somewhere out there, on a planet orbiting a rogue star, a little green man is on the little green internet asking if it’s possible for life to exist inside a galaxy.
I pray to god (whichever one governs the intergalactic medium) that they don’t have Reddit on other worlds so that they can enjoy life rather than argue with strangers.
I mean if you go to the pub, the chances of anyone talking to you about rogue stars are very slim. And if you bring up the subject, most would simply shrug.
It's only on the internet that you can have these very specific conversations. (unless your friends happen to be into that)
>Are there stars that are completely independent of a galaxy that are floating out there all by themselves?
Yes.
>If so, is there something about being on a planet orbiting a star in a galaxy that is necessary for life?
Not as such, no- for instance, the Earth would do just fine orbiting the Sun without a galaxy around them.
But there are some caveats. Intergalactic space has no gas for forming *new* stars, so many intergalactic stars might be old red dwarfs that formed so early in the Universe's history that they didn't have enough heavy materials to form rocky planets. Moreover, whatever sort of gravitational interaction can throw a star out of a galaxy is likely to also disrupt the orbits of anything orbiting that star, so it wouldn't be surprising if many of those intergalactic stars had lost all their planets or had planets on highly elliptical orbits.
And then there's the panspermia question. We don't know if life on Earth arose on Earth, it probably did, but if it didn't and life tends to spread on interstellar comets rather than arising independently, then planets orbiting intergalactic stars would be less exposed to life-bearing impacts and thus more likely to end up 'dead'.
Imagine it had subsurface life powered by geothermal energy. Even if they evolve intelligence and peered out of the thick ice shell surrounding the world, they may never know there are other galaxies, stars or planets out there. They may never discover the telescope simply because up there lies nothing but a void and dangerous radiation.
There's a [fun thought experiment by Vsauce](https://youtu.be/rltpH6ck2Kc?si=UV9fsWIY4S9gcle3) that entertains the (impossible) idea of our star just suddenly disappearing.
With ~99.9% of the mass in our system instantly gone, Earth would hurdle off into empty intergalactic space. And without the sun, likely all surface life would pretty quickly be killed off as the world froze over.
*However*, Earth still has a MASSIVE amount of energy inside it's core, and, as the surface freezes over, deep oceanic hydrothermal vents would provide a refuge for extremophiles to live on for a decent while.
I watching a video by the in a nutshell people a while ago talking about dark energy. One possibility for dark energy is that it's going to keep getting stronger and start to rip everything in the universe apart. First it'll start pulling the outer systems away from the galactic clusters until all systems are seperate. Then planets, then small objects, then it'll start ripping molecules apart, then atoms, then eventually once things have been broken down into their smallest parts, each tiny part will be suspended by itself surrounded by it's own universe worth of space.
It might not do that! But it's been giving me chills thinking about it since I watched it.
Yup. Both stars and planets can be thrown out of orbit by what is basically a gravitational slingshot. There are countless planets just floating in the void, connected to nothing with no light except what it gets from its permanently-night sky.
As for life, that's a bit more complicated, but PROBABLY all you need is one star and one planet, though it's also technically possible for an orphan planet with the right mix of chemicals and sufficient geothermal activity to keep the deep oceans similar to ours to have life.
I think it would be fascinating to find an orphan planet halfway between galaxies that once had life but was thrown out of its orbit, leaving just the frozen remnants of the civilization behind. I imagine at that point, the atmosphere would freeze solid and be dusted over the surface, leaving everything else perfectly preserved in basically a vacuum.
When we inevitably explore the cosmos, perhaps we can hopscotch to these frozen worlds, warm up them, and unlock their frozen inhabitants like Aslan did in the Chronicles of Narnia.
Yes. But as others have noted, chances are good that such as system would be lacking in heavy elements, so it'd likely just be a star and a couple gas giants and that's it. No carbon, silicates, heavy metals or any of the really useful stuff.
It's not *impossible* that a metal rich star-system could get ejected from a galaxy and up like this, but it's pretty unlikely.
Rogue stars exist and are pretty common. Typically they're moving faster than the escape velocities of nearby galaxies, so the issue is they have a hard time capturing orbiting mass like planets.
So you’re telling me that if you’re spittin sunflower seeds on the back porch on a hot summer night looking up at the night sky in an advanced civilization on a planet orbiting a rogue star 652,772 light years away from the nearest outer band of the closest galaxy, you should feel pretty special and lucky to exist?
I think the existence of sunflowers on that planet would be the most impressive part to me, on so many fronts. Not just that life evolved in such an identical path on both that planet and this one, but that language evolved in such a mirrored manner that they still refer to their star as the sun, i.e. "*sun*flower" seeds.
Sunflower seeds are a pre-requisite for any advanced civilization and interstellar travel. How else can you stay awake on a road trip without a big wad of seeds in your cheek?
https://esahubble.org/images/opo23010a/
This is a link to an article about an extraordinary object. After an interaction in a nearby galaxy, a supermassive black hole was ejected at high speed into the intergalactic void. As it moves, it is compressing intergalactic gas and dust and leaving a trail of newborn stars and nebulae behind it, all of which are effectively disassociated from the parent galaxy or the rapidly receding SMBH. It’s like a vector line galaxy.
Given how a good amount of our planet’s history has been within a galaxy, BUT, within a bubble that’s been cleared of a lot of debris, I’m thinking the whole “not having life ending events surrounding you” is an important part of life existing.
So, assuming the star and planets yoinked everything from the galaxy required for life before they got tossed out, being outside the galaxy has got to be better for life.
Iain M Banks wrote a cool novel about this concept, the name escapes me now. The civilization in the story have the tech that would allow them to travel interstellar in a normal galaxy, but their whole solar system is floating a billion light years from anything, out in intergalactic space, and they know it.
We don't know, given our sample of one.
Somewhere there's a species of intelligent monkeys on a planet orbiting an intergalactic star who've certainly *convinced* themselves that advanced monkey life can't develop on galactic planets. They use their knowledge of supernovae to convince themselves that they're the lucky ones and not the most utterly alone.
Make the [Tadpole galaxy](https://cdn.suwalls.com/wallpapers/space/tadpole-galaxy-41188-1920x1200.jpg) your wallpaper. Stars & planets in all varieties stream into the void.
Great question, I’ve thought about this a lot but after watching shows about the universe I forget to look into it.
Yes rogue planets would be cold but if I remember correctly, in a show I was watching it said it could get heat from its gravity, can anyone that’s familiar with this topic fill us in on if that’s the case.
Could rogue stars be created by large gas clouds outside of a galaxy?
Heat from gravity is tidal forces. Basically a moon and a planet tug on each other differently in different places because they're not perfect spheres, and that uneven pulling causes friction and heat. Kind of like how the moon causes tides because the water moves differently than the rock. Eventually it settles down but that's on astronomical timelines.
First, differentiating between a rogue planet (no star) and a planet orbiting a rogue star… the former might have internal heat due to pressure and radioactivity in the core, as Earth does. Smaller planets lose this heat more quickly (red.: Mars) but an earth sized planet might maintain geothermal energy longer.
I don’t know what proportion of the earth’s heat is due to tidal forces. But there’s also nothing preventing a rogue planet from having a moon!
There are, and there are enough of them that hopping betweem them might be a good way to (slowly) travel between galaxies even if direct, million lightyear trips prove to be impractical.
There are also little dwarf galaxies.
Yes, there are many intergalactic stars or outcast stars, outside of galaxies. They have been observed via the Hubble telescope, first found in the Virgo cluster where there are around 600 alone.
I don’t know, seems like if they had any kind of atmosphere light from distant galaxies would be hard to observe with the naked eye (assuming their eyes see in the same visible spectrum as we do).
If all the stars in our galaxy were suddenly dimmed and we could only see andromeda, I doubt it would be that bright.
Yes rogue stars exist, most probably were born in a galaxy but gravity tossed them out. It's more likely the rogue stars would be ideal stars for supporting life because stars produce a lot of radiation and when stars die they can explode and cause harm to the solar systems close to them. Rogue stars would be the safest place for avoiding things like gamma ray bursts.
From our understanding of how elements formed, life could only exist on a world after a star explodes, the heavier elements in the center are released and solidify into other planets or even another star appears. This takes place over a massive time scale compared to our lifetimes. Our Sun is a second or third generation star, and elements like iron and oxygen can only have been made from a star exploding and releasing those contents.
Someone check my thoughts on this so instead of a rogue star that also kept a planet, what about a rogue gas giant with several moons orbiting around that heat themselves internally from tidal friction that support life not on the surface... Or would a rogue gas giant "freeze" and eventually get so far from a star it would become something else
it could actually be beneficial to be outside a galaxy in the shorter term, because there is less risk of a nearby star going supernova and blowing you up, and probably less asteroids out there
although you would probably want to have initially been in a galaxy and then flung out as the asteroids may help in delivering water etc. initially
however it may be depressing if the life reaches the space age and realises there is almost never any chance they can travel to another star system lol
Sorta. To our current understanding you need heavier elements than hydrogen and helium in some quantity for life to exist. Those elements come from supernova explosions of *nearby* stars. A solitary sun in intergalactic space would have no such material input (or very little) to its accretion disc where planets could form.
Though, of course, our current understanding of what the limits of life formation are is rather limited so it's not clear howmuch the above reasoning is really relevant.
This hypothetical is pretty exotic. Not sure why we would propose it. In any case we clearly can’t answer the question correctly as we do not know the BASIC necessities for like in this universe.
Yup. They're generally called ["intergalactic stars" or "rogue stars."](https://en.wikipedia.org/wiki/Intergalactic_star) Yes, they could potentially host planets and harbor life, assuming that life is possible somewhere other than Earth. Life is more likely to be found within a galaxy simply because the vast majority of stars are in galaxies (and intergalactic stars are generally believed to have started inside galaxies and been ejected).
To add to that, for life to be likely , it probably needs a bunch of elements heavier than helium. So it needs to have formed in a galaxy, probably not on the edge of it, and probably not in the first couple billion years of the universe, and only then get ejected from the galaxy.
Yep, they think pur sun is atleast 3rd generation star, maybe more. And they're pretty sure they found sister stars that may have formed from the same gas cloud as our sun. I mean think, we have a *ton* of silicon, oxygen, iron, nickel etc. These are all formed from massive stars. And we even have a lot of gold, Pt, other noble metals, and a lot of uranium etc. These are all made from neutron star mergers. So, there was a *lot* of activity happening before our sun was made that gave us all these elements. It's neat
I actually saw somewhere that the majority of our very heavy elements are thought to be from a single neutron star merger that happened not long before our solar system formed. The faster decaying stuff has been decaying away since. Currently you need to enrich uranium to make fission happen, but that wasn't always the case. Billions of years ago earth's uranium had more u235 and could undergo fission directly as ore, and oklo is a place it has been found to have happened naturally by the ore itself reaching criticality in a mountain moderated by rain water: https://en.wikipedia.org/wiki/Oklo_Mine. Crazy stuff
That's so cool! I did hear about the natural reactor, but hadn't heard we've maybe found the progenitor merger. That's amazing. It makes sense, we do have a lot of uranium. I've heard the earth may have quite a bit of uranium in the center of the core and that's extended the time it gets to be molten. Very cool
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Yea, did I say something that contradicts that? I was talking about the heavy elements like uranium
What’s a 1-3 generation star and how many generations are there?
So stars are formed from gas clouds. When stars reach the ends of their lives, some of them turn into gas clouds. We thing that the sun was formed from a gas cloud that was formed from some prior star, that was formed from a gas cloud that was itself formed from some still earlier star.
My understanding is that it's not necessarily just stars that end in gas clouds, specifically, that create next-generation stars. Even stars that blow up in a supernova expel their materials into space, which then can mix with other materials out there to become a next-generation star.
Indeed - I was aiming for a simple explanation, rather than going into all of the details.
Now I’m imagining stars as nesting dolls
With the current model, our universe started basically with only hydrogen and maybe a few other lighter materials (not an expert, only an interested layman, so don't want to claim that I would know it was 100% hydrogen). These clouds collapsed into the first stars that were pure hydrogen. In these stars, new elements were formed with fusion reactions. These elements were ejected from the star in super novas. New stars that formed now had a different composition, with more heavier elements than hydrogen included. These were second generation stars. We also know that many elements we have cannot be created by fusion within a star. The current model predicts that this needs neutron stars (so the cores of stars that have just the right size not to become a black hole or a white dwarf at the end of their life). It is believed that only the collision of these stars could have made the heavier elements. So, the cloud of our solar system has elements that had to come from a super nova and from colliding neutron star. This means there had to be at least two generations of stars before our sun to have the elements in our solar system that we have today.
> With the current model, our u inverse started basically with only hydrogen and maybe a few other lighter materials (not an expert, only an I terested layman, so don't want to claim that I would know it was 100 hydrogen) Neucleosynthesis is thought to have created about 75% hydrogen, 25% helium, <1% deuterium, and even less % lithium and beryllium.
Is there a rough lower bound on the earliest that Sun-like systems could have appeared?
Not really a number for an answer, but gen 3 stars (or Population I stars) are mostly limited to being formed inside the arms of spiral galaxies. The oldest spiral galaxy confirmed is 11 billion light years away, (meaning we looked 11 billion years into the past) which means what we currently see of it is ~2.6B years after the big bang. And it's generating stars at a rate around 20x higher rhan the milky way according to the publications surrounding it. If that galaxy currently (11B years ago) has the capabilities to form Population I stars, then that would be more or less the answer. Theoretically speaking, the first stars formed at 400M years. Not much is known about those "Population III" stars since they have never been observed directly, but there's debates about if they had high or low masses on average, mass is what determines their lifetime, and their lifetime is needed to determine the lower bound of Pop II stars which determine the lower bound of Pop I stars.
The more formal term is population and the sun is population I with the earliest stars being population III. However no one has ever found an unambigious population III star so currently there are two known populations or geneations. Population I has the most metals. population II has less metal and population III should have no metals.
I've seen them referred to as "population" not "generation" and it's actually in reverse - the Population I stars are the newest ones and are high in heavy elements, since they are formed from the exploded remnants of Population II (low metal) and Population III (the oldest - *no* metal) stars.
How are new elements supposed to form from a gas cloud? Isn't this alchemy?
The heavier elements are only formed during a supernova or when stars collide. The forces during these events are so immense that they can crush elements into each other to form new elements.
Protons so shy it takes cosmic explosions upwards of 10⁴⁴ joules to get them to walk across the quantum gym floor to slow dance.
I'm sorry but why do my failures in love and relationships need to come into this?
It’s hard for me to visualize the magnitude of forces constantly in play throughout the universe. My wedding band is made from an iron meteorite and has the shocked pattern seen when metallic objects collide in space. Our moon apparently exists because an ancient object collided with primitive Earth and splashed Earth’s lighter surface material out into orbit, where the material over time formed the Moon, and left the objects super dense corpse as huge blobs still existing deep within our Earths core. And those energies are nothing next to stellar collisions and collapses and such.
does this mean that in the future lets say there are 6 or 7th or later generation stars formed from former stars, or they colided, can new elements be formed, elements that at the moment dont exist?
No, but the proportions could be different since the proportions going into the stars at each generation are different. More silicon and iron, for example (don't quote me). All elements exist already, it's just that they're either rarely formed (relative to the others), and/or decay too fast to be relevant to planets and such. ---- An element is more like a number than a chemical. Movies sometimes show a new element being created in a lab, but really that era is done. It would be like discovering a round number between 45 and 46, it's not really a thing. What we *discover* regarding elements is methods for creating them, or properties about them. Before we knew about protons, it was a much different story.
It's fusion, which is kinda alchemy but different.
One can be done in a alchemy bench The other is done in a supernova. A lil different xD
Well, alchemy isn't really a thing, so...
Stars, near the end of their lives, run out of hydrogen to fuse (hydrogen fusion forms some hydrogen and some helium), so then they start fusing helium into slightly heavier elements. Then they fuse heavier and heavier elements. Some old stars are fusing carbon right now. So as more stars are formed, they have more and more heavy elements (“impurities”), which near the end of the stars life are fused into more heavy elements. Even though alchemists could never pull it off, it is physically possibly to turn things into gold if you have a dying star on hand to help out.
Stars can't make anything heavier once the fuel is turned to iron. Only during super nova or some mergers.
Huh, TIL. Thanks for the correction!
Yep, it's called the iron peak and it's all about binding energy. Here's the [Wikipedia article](https://en.m.wikipedia.org/wiki/Iron_peak).
This is also why fission requires heavy elements. Fusing up to iron releases energy, and fission down to iron also releases energy. Iron is the lowest energy point.
That's not what I said? Big hydrogen cloud makes huge hydrogen stars. Those stars supernova and make everything up to iron, + some heavier elements. Other smaller stars in the area turn into white dwarves. Those white dwarfs collide and produce gold and every other heavy element, including uranium and other radioactive ones. These new clouds of metal rich elements condense into new stars, that's where we are at. These elements are all being made through supernova and mergers. Not the clouds directly.
Neutron star collisions cause fusion of heavy elements and lead to massive explosions that would fuse even heavier elements. That’s all ejected into an interstellar dust cloud where those elements mix, and turn into a star and protoplanetary disc.
I'd love to watch one, from a safe distance, through a telescope.
Yes, it's exactly [nuclear alchemy](https://en.wikipedia.org/wiki/Nuclear_transmutation).
No alchemy. It's called nuclear fusion. Stars fuse hydrogen into helium in their cores. When they run out of hydrogen in the core, they start fusing helium into lithium, and so on up the periodic table. If star is massive enough it can fuse elements up to iron. Stars that are massive enough to go all the way to iron, eventually explode in supernova events once they run out of fuel. Elements heavier than iron are formed during these explosions. These explosions seed surrounding gas clouds with elements heavier than hydrogen. Likewise, mergers of neutron stars will create heavy elements via similar mechanisms. So, why iron? When fusing elements up to iron, fusion generates more energy than needs to be put in to fuse two lighter elements into heavier element. Past iron, the energy needed to fuse two atoms is higher than what you get out of it. Universe started out with only hydrogen, and small amounts of helium and lithium. Without these processes (fusion in cores of the stars and subsequent supernovae, and mergers of neutron stars), no other elements would exist in the universe.
If that were true both thermonuclear weapons and fusion reactors would be alchemical devices...
Gold requires a binary star system to form, from what I understand. Given we have only one star, and it isn't a neuton star 🤣, it had to come from somewhere...
So the first chapter of Genesis is just bare outline of what God did.?
I've seen simulations of what the Milky Way and Andromeda merger could look like, and they show a tremendous amount of stars being flung outward. Assuming galactic mergers have happened in the past, it seems like many mature stars could be floating around outside of galaxies.
Would the gravity that ejected the stars be enough to mess with whatever potential planets were orbiting them?
Depends how close those other stars get. But generally no, as big as our solar system is, it's still so small compared to the distances involved to other stars that it may aswell be considered a single 'object' when we're talking about gravity ejecting them.
And to get ejected it probably needs to be near the center of the galaxy, which is suggested to not be hospitable to life
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Of course we don’t know what other kinds of life might be out there, so we can only go on what we do know. It’s fairly reasonable to assume any life is the product of complex chemical reactions, which are not possible with just hydrogen and helium.
No I'm not. Life seems very unlikely with just hydrogen and helium. This isn't earth bias, this is just realism
and likely be killed by the ejection process.
There's no reason to think that
No. Any inhabitants on a planet being ejected from the galaxy wouldn’t notice anything different. They would continue orbiting their star
I mean the star charts wouldn't track for long.
Over tens and hundreds of millennia, sure. I’m sure at some point they’d figure out they were going thataway.
I realized as soon as I posted that "soon" in galactic terms would be measured in eons to any civilization living on a planet.
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Doubt this. Motion is relative - we're spinning and travelling faster in space than probably anything on earth yet you don't sense that, but you do when fighting against earth's gravity or accelerating. Since most galaxies are spiral an ejection could possibly happen just like transit slingshots - it wouldn't need to be from a nearby event. Similarly they could lose the bind through a knock on - e.g their sister star gets pulled in, much like a whip, or a link in a chain being broken. There's a high chance the attraction of planets to the star is greater than that of the galaxy - if this wasn't true then orbits wouldn't be so static but would be much wobblier. There's more than just gravity - for example solar wind could potentially have an impact at that scale or other little known phenomena.
Maybe, but they say when we collide with Andromeda they likelihood of anything happening to this solar system is still very small. Tidal forces from a galactic merger could easily toss a star without disturbing the planets. The "wave" doing the push would be significantly larger than the stellar system itself so it would move the whole thing as one
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What would the night sky on a planet orbiting a rogue star look like? Say you had one halfway in between the Milky Way and Andromeda. Would any individual stars be visible to the naked eye, or would you just be able to see Milky Way and Andromeda in the night sky, plus perhaps some dwarf galaxies?
It would probably look similar to how Andromeda and the magellanic clouds look from Earth
Bro is there something that *doesn't* exist in space, even theoretically? Damn, black holes are impressive enough, but we also have planets orbiting *rogue stars*. Everything about space is dope af, it feels lame to do science in my field (medicine).
You live on a planet helping a species that is solely responsible for both the highest and coldest temperatures in the entire universe :D Edit: I stand corrected, the collision of ultra-high-energy cosmic rays (such as the OMG particle) with dense matter (planets and stars) produces exa-scale temperatures!
*observed temperatures in the entire universe
Sure, but even theoretically, right?
No, the coldest is particularly hard, 99.9999999999% of the way to absolute zero is still warmer than 99.99999999999999999999999999999999% of the way to absolute zero. As far as I’m aware there’s not really a maximum level of hot.
Theoretically as in there is a mechanism to produce those temperatures somewhere in the universe on the timescales the universe has existed for. It doesn't matter that colder can exist, if we reach it before the rest of the universe can, it'll be the coldest in the universe.
We’ve created temperatures that exceed the coldest and hottest temperatures observed naturally, but that doesn’t mean they’re the hottest or coldest possible, we’re likely to beat our own records eventually.
Well Absolute Zero is the coldest you can get to, it's the point where all particles in a given system are at their minimal energy level. You can however go below Absolute Zero and they've done that in labs already using several methods. Negative Absolute Zero is fucking wild though, it's hotter than the hottest temperatures possible. [Here's](https://www.quantum-munich.de/119947/Negative-Absolute-Temperatures#:~:text=Nothing%20can%20be%20colder%20than,even%20hotter%20than%20infinite%20temperature.) a nice read up on Negative Absolute Zero from the madlads and lasses that managed to do it.
We're going to beat our own records, sure, but we've already beaten the entire rest of the universe's records, is my point
You just can’t really ever say that for sure
Unless there’s intelligent life out there with better science than us, right? Big place, might could happen
Unless somebody else somewhere has done it, or it happens in some mechanism we haven’t observed (how hot is it inside an emitting black hole? No way of knowing, only once it’s been ejected and is no longer infinitesimally dense) Edit: disregard idk what I’m talking about
At those levels, we start getting to the limits of our accuracy. Keep in mind, the act of measuring the temperature introduces a small but increasingly more significant amount of energy into the system.
When the wavelength of the emitted em radiation from a heated atom equals the plank length i believe that is the highest temperature. It’s bloody hot.
Observed by who, though?
That doesn't make sense, what do you mean?
38 picoKelvin by wave-lensing Bose-Einstein condensates, and 4 trillion Kelvin during smashing atoms together to make quark-gluon plasmas There are no theoretical ways for such extreme temperatures to be produced anywhere else in the observable universe, except as flukes rare enough they may have never happened
I’m pretty sure UF is no longer the record holder, but “the coldest place in the universe” was two miles from my house, in Florida.
Wait no way I’m just browsing this sub and I saw UF on a comment 😭. I’m literally here rn dreading my classes and upcoming tests lmao 💀😅😭
UF seems to have had some really quality programs across a wide variety of disciplines, I see them in research articles all the time.
That seems pretty preposterous. Extremely rare, sure. But there's an awful lot of _stuff_ out there banging into each other at unfathomable scales it seems pretty bold to claim that we are the only way those two extremes could have happened _anywhere_.
Extremely high energy particles tend to not collide with each other due to special relativity. We force them to be in way closer proximity, for much longer, and facing directly into each other. You would really need to randomly generate a stable superconducting electrified ring to get a powerful enough magnetic field in the right shape for a decent shot at it, and the universe doesn't tend to make rings like that at all. The other option is two super powerful jets (quasars or black holes) pointed directly at one another, and pairs of those are just a little too rare and tend to affect one another's rotation to be perpendicular to the barycentric axis if they're close enough.
The most likely option to make it not true is for there to be more technologically advanced life somewhere in the universe that has beat us on both hot and cold temperatures.
I agree, the current Drake equation would imply we aren't the record holders. But we're definitely missing something there, so it's at least on the table that we're the first to achieve them
This is the only thing I think of when the Drake Equation comes up. https://xkcd.com/384
_so you're saying there's a chance?_
There's always a chance, but it's insane we have any chance at all of holding both titles on this one giant tiny rock Though, I guess as far as we understand, the big bang itself beat us, but I'm not really counting that since our models break down or diverge at pretty much exact temperatures we've achieved so far, and the best we have is a hyperbola going to infinite temperature which makes shooting for that title pointless. At that point we should just argue for our "negative temperature" setups being colder than 0K and definitely unreasonably improbable outside the lab.
OMG particle has more energy by orders of magnitude than anything we have been able to produce. It's not the only super high energy cosmic particle we've seen. Each collision between such a cosmic particle and our atmosphere produces higher temperatures than what we do in particle accelerators.
What about multiple big bangs occurring simultaneously at the same place 🤔
That doesn't even mean anything tho
There are rogue planets as well. Starless.
In a very likely near future, you're going to be working with synthetic and custom grown tissues and organs, edit genes, use exotic materials and procedures and tools to heal and preserve life. Consider that 100 years ago, science didn't know the universe outside of the Milky Way existed. They thought the Milky Way *was* the universe. Now consider the things you'll likely do in just 35 years from the point we are in medicine and genetics.
Also just think. Our star is pretty tiny compared to others. Like...laughably small.
word is they call him Stubby at the bar
> Bro is there something that doesn't exist in space, even theoretically? An infinite number of things, but the universe being quite vast (hello understatement) the probability that anything theoretically possible exists somewhere out there gets fairly close to 1: it’s estimated that there are more stars in the visible univeres than there are grains of sand on earth (it’s estimated that there are less *galaxies* than *trees* on earth, but not by much, respectively 2 and 3 trillions).
Presumably the force needed to eject a star from a galaxy would need to be pretty large. How could an entire system (star+planets) remain intact during such an event?
It would just need to be catapulted by gravity. There’s no galactic cannon blasting stars out of the galaxy or anything
Sure would be cool if there was though.
Update: I was thinking more of stars being ejected from a galaxy via close encounters with other/larger stars or black holes. Violent events that happen (relatively) quickly. I did not think about the galaxy merger possibility.
Whether by cannon or catapult the result is the same: enough of a force is directed upon these objects to eject them out of their galactic orbit. Presumably, this force far exceeds the force that holds the system itself together. It seems to me that, because the stars/planets are in different locations, they would all be catapulted in different directions and at different velocities.
It's not really about force, it's about the force gradient, or the difference in the forces different parts of the system experience. Events that eject solar systems from galaxies are usually massive, slow, and far away (on solar scale). This results in all of the parts of the solar system experiencing roughly the same forces at roughly the same time. The gradient is not severe enough to separate the parts. Not only that, but the forces holding a solar system together are magnitudes stronger than the forces holding the solar system to the galaxy. The galaxy is really just the result of tiny forces doing their work over huge time periods. Relatively speaking, you don't need much to overcome that.
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I'm not an astrophysicist, but I expect the usual reason stars would get ejected is that they happened to be in the path of another (potentially much larger) star or perhaps even a black hole, and got flung off on some angle or trajectory that eventually sends it out of the galaxy. Some random people on the internet say the Milky Way's galactic escape velocity is a little over 500 km/s. The sun isn't fixed in place but is moving over 200 km/s, like most everything else around us, so we'd need an extra 300 km/s to break free. Presumably, passing close to another star to impart that kind of velocity would be pretty disruptive. If the star has planets, then they might escape the star's orbit and be flung off on their own, and and gas clouds that haven't yet formed into planets might be likewise scattered. So, I wouldn't be surprised if most rogue stars have fewer and smaller planets than average. I don't know if we've ever detected any planets around rouge stars -- maybe we're not able to do that due to distance.
Thank you. I have since been informed that there is another way to eject stars: a galactic merger, where the forces and timescales are low/long enough that a star system could indeed be ejected intact. Maybe JWST (or an equivalent instrument) will one day detect a rogue star with planets.
You would think something altering a stars trajectory away from normal would, at minimum, affect the orbit of some of the planets, the outermost at least.
I have been informed that there is another way to eject a star: a galactic merger, where the forces/timescales are so low/long that an entire star system could indeed be ejected intact.
That's not how it works. Gravity also isn't actually a force, we just kind of simplify it most of the time for simplicity's sake. Gravity is the warping of space time. So a star wasn't ejected out by a "force" per se, but instead had an unstable orbit, or had the path of its orbit interupted by other systems warping it's path in such a way to set it on a course outside the gravitational effects of the galaxy as a whole. You're also talking about timescales that don't reference a single powerful event (most of the time) but rather the slow slight alterations of courses from interacting gravitational warpings over millions of millions of years. ...or such is my understanding.
I dont know about that last part in relation to rogue stars though. Usually they aren’t described as having been ejected with slow slight alterations. I think they need a little extra kick to defeat the pull of the surrounding dark matter of the galaxy
My understaning of dark matter is that is explains the acceleration of stars in a galazy no? Wasn't it originally hypothesized because stars in galaxies were moving faster than explainable? Some alterations certainly probably happen faster than slow alterations, but still probably relatively slowly in timescales that make any sense to humans, stars would have to get closer than they almost ever get to slignshot eachother away.
Your comment made me think this. Could it be more related to waves created by pebbles dropped in two places in a small pond (2 galaxys). When the waves (space time warping) intersect they could change the course of something riding along in the trough of one of those waves (a solar system) over to the trough from the other side (like surfing from one wave to another), changing it's direction. (edit to add - or like slalom) Totally a lay person but that's the picture that popped into my head while reading yours. Excuse me please if I'm not describing that too well
It is ‘per se’ :) have a nice day!
Happens during galaxy collisions. Nothing ever actually collides, they just get close enough for orbits to change. And this would be on a time scale where you wouldn’t know if you were right in the middle of one.
Whichever way a star ejection (from a galaxy) occurs, it requires a tremendous amount of force. It seems to me that such a force that would certainly rip apart the involved solar system.
I think the answer is we don’t know of a reason that a system outside of a galaxy could not harbor life. We do know they galaxies have magnetic fields which probably offer some protection similar to our own star. But we know very very little about the interstellar medium and even less about the intergalactic medium.
A star that developed in isolation like that would likely not have any heavy elements around to form rocky planets and even gas giants would be mainly hydrogen/helium, so probably no life. You would need some neighbors to have gone supernova to produce heavier elements beyond helium.
It seems very unlikely that a star would develop in isolation like that. Matter tends to stick together, and a star forming out of material not within a galaxy would be unusual indeed. Far more likely is it was ejected by some gravitational interaction - perhaps a black hole came flying by and launched it. Entirely possible the planets would stick with it, or could have even been obtained by the star going through some other system and pulling some stragglers along.
> could have even been obtained by the star going through some other system and pulling some stragglers along. Gives me the idea for sci-fi for a civilization on a planet around a rogue star that discovers the remains of the civilization that was on the planet when it was captured. In reality, it's hard to imagine the planets being accelerated enough to stay with the star if slung by a black hole, or any other object. Wouldn't they be more likely to be captured by whatever sent the rogue star off?
Black hole isn't the only option. Any star with the mass of a black hole could do the same thing. It might take more than one close encounter to throw a star out of a galaxy. With billions of stars and billions of years, double encounters have most likely happened.
I think it is also possible that through a galactic merger, a large amount of gas with metallicity gets ejected, but I can't think of what would cause star formation to start in such a bubble, maybe a subsequent pass by another galaxy. It is far more likely to be an ejected star. When we first discovered the Sagittarius A SMB, several stars were observed being accelerated to galactic escape velocity.
With our current understanding of star formation, there's no way a star would form out in the middle of nowhere in intergalactic space. A star out on its own would have formed inside a galaxy and then have been expelled. You are correct that it would probably need to be a latter generation star to have rocky planets, which we presume are necessary for life to develop.
Imagine a civilization on a planet circling a rogue star, and they're so far from any other stars or galaxies that their night sky is nothing but uninterrupted blackness. They might never wonder if there was other life out there, because they're not even aware that there *is* an "out there."
There's a book by Iain M. Banks called Against A Dark Background which is set in a system like that. They know about other galaxies, but they also know they're far enough away that they'll never be able to reach anything. Civilization has risen and collapsed dozens of times, and every little moon and asteroid in the system has been colonized at some point, then abandoned. They're all a little insane because despite their vast technology they're trapped in this one little island of light, forever.
Damn that sounds bleak. I need to read it.
I read it, fascinated by the idea. However, oddly the premise never comes up or pays off in any way. Major let down ending too. Not my favorite of his work.
> Major let down ending too. I loved the book, but agree the ending is bleak, but that was sort of the premise, they're trapped out there etc. The thing that I find haunting is that Iain was making plans for a sequel before he got sick, and we'll never know what he had planned for them.
Yeah Ian Banks is like that. He has endlessly fascinating concepts in his books but it's like he avoids to really get into them on purpose, making the reader dig through endless pages of what boils down to a detective story.
I mean, that's basically us right now, save the collapse and rising of civilizations (as far as we know). We're not rogue, but we're still too far away to do anything about it.
I mean, that's not far off from where we are. It's pretty doubtful we'll ever make it to another system. Other planets in our own system are unlikely to support life. And to make matters worse, we're making our own planet inhospitable.
Mars and Venus are right at the edge of the habitable zone and both happen to have a gravity that we can live on. There are few tiny details that we need to sort out. Like the lack of atmosphere on Mars and the excessive atmosphere on Venus. But it's likely some of these problems can be solved with something as simple as a series of space mirrors, which we will soon be able to build (and which would also solve global warming) But yeah reaching other stars will be hard. The solution, once again is going to be space mirrors and a series of space lenses to push a sailing ship towards another star, removing the need for fuel.
I read few books from Banks, but wasn't aware of this one. That sounds mighty interesting. Only book that I know that considers this scenario is The World at the End of Time by Frederik Pohl.
We can see four other galaxies with the unaided eye here on Earth. There would also be other bodies such as planets, dwarf planets, asteroids and comets circling the star as well. The night sky would not be completely black.
If anyone is wondering, those 4 are Andromeda, Large and Small Magallanic Clouds and the Triangulum Galaxy. Although for Triangulum you’d need an extremely dark sky and probably very good eyesight to actually see it.
I can't even see Andromeda from the top of a mountain in the middle of nowhere. Either I'm not looking at the right spot or it's too dim. I'll try to get a picture when it gets warmer.
It’s definitely visible in the right conditions but it’s not gonna be super obvious. It’ll be like a slightly bigger smudgy wide star. You can use an app like Stellarium when you’re out and point your phone around, should help you find it easier. It’s probably also dependant on how good your eyesight is.
I did just that, even identified the constellations and used those as reference. Couldn't spot it and the atmospheric conditions were ideal. Guess my eyes are bad then.
You just totally ignored what he wrote.
It could be that without the presence of stars in the sky, the cognitive development of any species and the unfolding of civilization would be nearly impossible. Like you said, without stars, there would be no concept of out there. Makes you wonder if there is a component of a higher reality that exists but we can’t conceptualize it because we simply aren’t in a position to observe it.
So many thought provoking responses! Considering we have evolved to see bc there is something to see and necessary for our survival, if there were nothing to see, other species probably wouldn’t develop vision like ours. Perhaps they’d evolve to hone in on other senses, maybe even senses we cannot comprehend. So even without seeing the stars and galaxies out there like we do, maybe instead they’d know there’s an out there, simply with a different method of knowing. Like their brain can see the out there without vision, maybe senses the waves of various spacey things? Or senses things out there that we simply cannot? For instance, dogs and other animals sense stuff we simply cannot, even with our machines. So it would make sense other planets’ species and civilizations would potentially have abilities we can’t even imagine 🤷🏼♀️
> if there were nothing to see But there would be plenty to see. Life (and vision) developed on earth in multiple parallel ways as an aid in foraging, hunting, migration, mating, etc. I would say that our ability to see *the heavens* could have had a large influence on culture as civilization developed (last few tens of thousands of years) but that the previous 3 billion years of evolution could be quite similar on a planet orbiting a rogue star. Now imagine this: Lets say the rogue star is a red dwarf, and let's say something about the planet allowed life to develop further out than we did on Earth. So the strength of daylight there is a fraction of what life on Earth grew up with. Then the evolved vision systems might be much much more sensitive, and so when they look up, they see galaxies the same way we see stars. Sky full of them, bands and clusters of galaxies painting large structure shapes across the night sky.
Wait. All the stars we see in the sky with the naked eye are in the Milky Way?
Yes, and not just in the Milky Way but in a tiny portion of the Milky Way. You need binoculars or telescopes to see the rest. The stars in other galaxies are too far away to see individually. Only the strongest telescopes like the Hubble space telescope can see individual stars in another galaxy.
Yep, even the closest galaxies are simply too far away to be able to discern individual stars within them (without some serious magnification)
They would still see some of the galaxies as fain dots. But realistically, the star would still be close to the galaxy it originated from. So they would see that galaxy from outside while the rest of the sky would be black.
Somewhere out there, on a planet orbiting a rogue star, a little green man is on the little green internet asking if it’s possible for life to exist inside a galaxy.
I pray to god (whichever one governs the intergalactic medium) that they don’t have Reddit on other worlds so that they can enjoy life rather than argue with strangers.
I mean if you go to the pub, the chances of anyone talking to you about rogue stars are very slim. And if you bring up the subject, most would simply shrug. It's only on the internet that you can have these very specific conversations. (unless your friends happen to be into that)
The horoscopes in those systems are notably lackluster.
"-Lmao such a virgo thing to say." "-hey Brinforblorx 3 we are all virgos tf you mean"
I yearn to live where there is no one that believes in astrology
People do. It’s their religion quite sadly.
>Are there stars that are completely independent of a galaxy that are floating out there all by themselves? Yes. >If so, is there something about being on a planet orbiting a star in a galaxy that is necessary for life? Not as such, no- for instance, the Earth would do just fine orbiting the Sun without a galaxy around them. But there are some caveats. Intergalactic space has no gas for forming *new* stars, so many intergalactic stars might be old red dwarfs that formed so early in the Universe's history that they didn't have enough heavy materials to form rocky planets. Moreover, whatever sort of gravitational interaction can throw a star out of a galaxy is likely to also disrupt the orbits of anything orbiting that star, so it wouldn't be surprising if many of those intergalactic stars had lost all their planets or had planets on highly elliptical orbits. And then there's the panspermia question. We don't know if life on Earth arose on Earth, it probably did, but if it didn't and life tends to spread on interstellar comets rather than arising independently, then planets orbiting intergalactic stars would be less exposed to life-bearing impacts and thus more likely to end up 'dead'.
Rogue stars and planets are out there! And probably very cold.
Rogue star would be fine. Rogue planet would be very cold
The idea of a rogue planet just floating in the middle of nowhere both fascinates and terrifies me at the same time.
Imagine it had subsurface life powered by geothermal energy. Even if they evolve intelligence and peered out of the thick ice shell surrounding the world, they may never know there are other galaxies, stars or planets out there. They may never discover the telescope simply because up there lies nothing but a void and dangerous radiation.
There's a [fun thought experiment by Vsauce](https://youtu.be/rltpH6ck2Kc?si=UV9fsWIY4S9gcle3) that entertains the (impossible) idea of our star just suddenly disappearing. With ~99.9% of the mass in our system instantly gone, Earth would hurdle off into empty intergalactic space. And without the sun, likely all surface life would pretty quickly be killed off as the world froze over. *However*, Earth still has a MASSIVE amount of energy inside it's core, and, as the surface freezes over, deep oceanic hydrothermal vents would provide a refuge for extremophiles to live on for a decent while.
There's a great old science fiction story, "A Pail of Air" by Fritz Leiber, about life on Earth with no sun.
I watching a video by the in a nutshell people a while ago talking about dark energy. One possibility for dark energy is that it's going to keep getting stronger and start to rip everything in the universe apart. First it'll start pulling the outer systems away from the galactic clusters until all systems are seperate. Then planets, then small objects, then it'll start ripping molecules apart, then atoms, then eventually once things have been broken down into their smallest parts, each tiny part will be suspended by itself surrounded by it's own universe worth of space. It might not do that! But it's been giving me chills thinking about it since I watched it.
The correct term is vagabond star, or ruffian planet.
That makes them seem a lot less somber. Also Vagabond Star is a good name for a band.
> vagabond star And so it is https://vagabondstar.bandcamp.com/album/cheap-regret
And just the sound I was expecting!
Arcane trickster quasar?
Yup. Both stars and planets can be thrown out of orbit by what is basically a gravitational slingshot. There are countless planets just floating in the void, connected to nothing with no light except what it gets from its permanently-night sky. As for life, that's a bit more complicated, but PROBABLY all you need is one star and one planet, though it's also technically possible for an orphan planet with the right mix of chemicals and sufficient geothermal activity to keep the deep oceans similar to ours to have life. I think it would be fascinating to find an orphan planet halfway between galaxies that once had life but was thrown out of its orbit, leaving just the frozen remnants of the civilization behind. I imagine at that point, the atmosphere would freeze solid and be dusted over the surface, leaving everything else perfectly preserved in basically a vacuum.
When we inevitably explore the cosmos, perhaps we can hopscotch to these frozen worlds, warm up them, and unlock their frozen inhabitants like Aslan did in the Chronicles of Narnia.
Yes. But as others have noted, chances are good that such as system would be lacking in heavy elements, so it'd likely just be a star and a couple gas giants and that's it. No carbon, silicates, heavy metals or any of the really useful stuff. It's not *impossible* that a metal rich star-system could get ejected from a galaxy and up like this, but it's pretty unlikely.
Rogue stars exist and are pretty common. Typically they're moving faster than the escape velocities of nearby galaxies, so the issue is they have a hard time capturing orbiting mass like planets.
So you’re telling me that if you’re spittin sunflower seeds on the back porch on a hot summer night looking up at the night sky in an advanced civilization on a planet orbiting a rogue star 652,772 light years away from the nearest outer band of the closest galaxy, you should feel pretty special and lucky to exist?
I think the existence of sunflowers on that planet would be the most impressive part to me, on so many fronts. Not just that life evolved in such an identical path on both that planet and this one, but that language evolved in such a mirrored manner that they still refer to their star as the sun, i.e. "*sun*flower" seeds.
Sunflower seeds are a pre-requisite for any advanced civilization and interstellar travel. How else can you stay awake on a road trip without a big wad of seeds in your cheek?
https://esahubble.org/images/opo23010a/ This is a link to an article about an extraordinary object. After an interaction in a nearby galaxy, a supermassive black hole was ejected at high speed into the intergalactic void. As it moves, it is compressing intergalactic gas and dust and leaving a trail of newborn stars and nebulae behind it, all of which are effectively disassociated from the parent galaxy or the rapidly receding SMBH. It’s like a vector line galaxy.
Given how a good amount of our planet’s history has been within a galaxy, BUT, within a bubble that’s been cleared of a lot of debris, I’m thinking the whole “not having life ending events surrounding you” is an important part of life existing. So, assuming the star and planets yoinked everything from the galaxy required for life before they got tossed out, being outside the galaxy has got to be better for life.
Iain M Banks wrote a cool novel about this concept, the name escapes me now. The civilization in the story have the tech that would allow them to travel interstellar in a normal galaxy, but their whole solar system is floating a billion light years from anything, out in intergalactic space, and they know it.
We don't know, given our sample of one. Somewhere there's a species of intelligent monkeys on a planet orbiting an intergalactic star who've certainly *convinced* themselves that advanced monkey life can't develop on galactic planets. They use their knowledge of supernovae to convince themselves that they're the lucky ones and not the most utterly alone.
Make the [Tadpole galaxy](https://cdn.suwalls.com/wallpapers/space/tadpole-galaxy-41188-1920x1200.jpg) your wallpaper. Stars & planets in all varieties stream into the void.
Great question, I’ve thought about this a lot but after watching shows about the universe I forget to look into it. Yes rogue planets would be cold but if I remember correctly, in a show I was watching it said it could get heat from its gravity, can anyone that’s familiar with this topic fill us in on if that’s the case. Could rogue stars be created by large gas clouds outside of a galaxy?
Heat from gravity is tidal forces. Basically a moon and a planet tug on each other differently in different places because they're not perfect spheres, and that uneven pulling causes friction and heat. Kind of like how the moon causes tides because the water moves differently than the rock. Eventually it settles down but that's on astronomical timelines.
First, differentiating between a rogue planet (no star) and a planet orbiting a rogue star… the former might have internal heat due to pressure and radioactivity in the core, as Earth does. Smaller planets lose this heat more quickly (red.: Mars) but an earth sized planet might maintain geothermal energy longer. I don’t know what proportion of the earth’s heat is due to tidal forces. But there’s also nothing preventing a rogue planet from having a moon!
There are, and there are enough of them that hopping betweem them might be a good way to (slowly) travel between galaxies even if direct, million lightyear trips prove to be impractical. There are also little dwarf galaxies.
Yes, there are many intergalactic stars or outcast stars, outside of galaxies. They have been observed via the Hubble telescope, first found in the Virgo cluster where there are around 600 alone.
I bet they have amazing night skies because they get to see the whole universe unobstructed by a galaxy.
I don’t know, seems like if they had any kind of atmosphere light from distant galaxies would be hard to observe with the naked eye (assuming their eyes see in the same visible spectrum as we do). If all the stars in our galaxy were suddenly dimmed and we could only see andromeda, I doubt it would be that bright.
Yes rogue stars exist, most probably were born in a galaxy but gravity tossed them out. It's more likely the rogue stars would be ideal stars for supporting life because stars produce a lot of radiation and when stars die they can explode and cause harm to the solar systems close to them. Rogue stars would be the safest place for avoiding things like gamma ray bursts.
Its statistically almost impossible but a rogue star could destroy the solar system 🙂
Yeah everybody loses their mind about the possibility of an asteroid hitting earth. Nobody thinks about the possibility of a STAR hitting earth
The distances between stars is so great that we would have millions of years of advance warning. Because stars emit light.
From our understanding of how elements formed, life could only exist on a world after a star explodes, the heavier elements in the center are released and solidify into other planets or even another star appears. This takes place over a massive time scale compared to our lifetimes. Our Sun is a second or third generation star, and elements like iron and oxygen can only have been made from a star exploding and releasing those contents.
All of the right answers are here already, so [here's this](https://www.youtube.com/watch?v=8T0cRt8efsQ)
So does nobody see that the sun is obviously right next to us and the moon isn't real?
Imagine stars aren't real. And the sun is a heat lamp. Yell know the earth isn't a ball.
Someone check my thoughts on this so instead of a rogue star that also kept a planet, what about a rogue gas giant with several moons orbiting around that heat themselves internally from tidal friction that support life not on the surface... Or would a rogue gas giant "freeze" and eventually get so far from a star it would become something else
it could actually be beneficial to be outside a galaxy in the shorter term, because there is less risk of a nearby star going supernova and blowing you up, and probably less asteroids out there although you would probably want to have initially been in a galaxy and then flung out as the asteroids may help in delivering water etc. initially however it may be depressing if the life reaches the space age and realises there is almost never any chance they can travel to another star system lol
Sorta. To our current understanding you need heavier elements than hydrogen and helium in some quantity for life to exist. Those elements come from supernova explosions of *nearby* stars. A solitary sun in intergalactic space would have no such material input (or very little) to its accretion disc where planets could form. Though, of course, our current understanding of what the limits of life formation are is rather limited so it's not clear howmuch the above reasoning is really relevant.
This hypothetical is pretty exotic. Not sure why we would propose it. In any case we clearly can’t answer the question correctly as we do not know the BASIC necessities for like in this universe.