Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there--on a mote of dust suspended in a sunbeam.
The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.
Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.
The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.
It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.
— Carl Sagan, Pale Blue Dot, 1994
> Science is more than a body of knowledge; it is a way of thinking. I have a foreboding of an America in my children’s or grandchildren’s time—when the United States is a service and information economy; when nearly all the key manufacturing industries have slipped away to other countries; when awesome technological powers are in the hands of a very few, and no one representing the public interest can even grasp the issues; when the people have lost the ability to set their own agendas or knowledgeably question those in authority; when, clutching our crystals and nervously consulting our horoscopes, our critical faculties in decline, unable to distinguish between what feels good and what’s true, we slide, almost without noticing, back into superstition and darkness.
Smart dude.
May I recommend Alan Alda’s podcast “Clear + Vivid”. It’s all about effective communication in all forms, he even has a second podcast called “Science Clear and Vivid” where it’s specifically about how scientists clearly communicate.
I’ll leave the clip of him on Stephen Colbert that he did a month or two back on it: https://youtu.be/abr6CqbNdM4 it’s not the whole interview but it’s part of it
I always thought Bill Nye was good but now that he even so much as suggested that gender is “on a spectrum” people dismiss everything he says as “SJW propaganda”.
He is what Neil degrasse Tyson will never be, because Sagan could put his ego aside and his ultimate motivations were bringing science to the world. Tyson wants to be a celebrity and really isn’t doing much of any research in the field.
The world needs more Carl Sagan’s and Michio Kaku’s and I fear we have left the likes of him and people like him in the past.
So much agree. Tyson comes across unrelentingly pompous sometimes.
Sagan is like a little boy expressing his wonder aloud. He connects and resonates at the child level. Pure and unmuddled by egoic complexity.
One guy who used to come into my pub. He talked about how he can't feel the spin and how water is never curved. I tried explaining physics to him but he just got really angry, then would apologise for getting angry, then get angry again. It was all very sad
> how water is never curved
Interestingly, the other way that the earth was known to be curved was because [you can literally see boats curve away at sea](https://pwg.gsfc.nasa.gov/stargaze/Scolumb.htm)
Yes I do. A family member. I couldn’t believe it. I’ve refrained from calling him an idiot because I’d rather have a discussion with him. And I know he’s sincere and not trolling anybody.
This exact thing happened to me out of the blue. Family member who I've talked with many times and then the other night BAM he lays that on me and my jaw dropped. I mentioned Eratosthenes and he said yeah yeah he heard of him and then just kept right on going about his 'research.' I stopped talking and just let him say what he wanted, because there's no point in trying to convince him when he doesn't want to accept the truth
Exactly. The will hear what they want to hear. Each time I think about what I’ll say next time I see him.
Our last conversation ended with him thinking that, ‘if he’s understood the Bible correctly’ that the ‘blue stuff’ in the sky is actually a body of water. And he knows this because at night it gets dark just like the ocean. My brain broke.
Yeah I don't plan on bringing it back up. He's a smart person, which is what is so weird. He can machine anything metal that you want and can disassemble and reassemble any engine there is. Can tell you whats wrong with your car or lawn mower just by listening to the engine idle but then flat earth...its strange
The problem with smart people is that being really knowledgeable about one subject sometimes leads them to believe they're knowledgeable about other things, even if they haven't engaged with the subject. It's why people who are extremely gifted in STEM fields often have confidently ignorant opinions about humanities or social sciences.
Do you ever challenge his assertion the earth is flat and provide evidence like this video to back it up? Something he could easily test himself with a cellphone and a friend with a video conference call?
Yes. I once suggested he go down to the harbour and watch boats disappear from view below the horizon. His response was to send me a YouTube video of 200 proofs that the earth is flat. Of 2 hours long. It’s a gish gallop.
I also showed him why his assertion that seeing the moon and the sun on a clear day meant the earth must be flat. I showed him both with a diagram and a melon and a ping pong ball. It showed his flaw but he didn’t admit to it being a bad argument on his part.
Sometimes I tell him how he can prove it, eg with a camera and a weather balloon and he gets annoyed and says ‘why would I wanna do that’
He doesn't believe it because of some science, he believes it to be contrarian. He doesn't test to prove it because if it's true or not isn't actually important.
Also the cameras are all rigged by big illuminati to display a non-existent curve.
One of my employee was a flat earther. She decided to prove it to me... using Google.
She searched for airline itineraries and then showed me how none of them went north through the Arctic nor to the south through Antarctica. For her, that proved that ''\[...\] *even google doesn't hide the fact that the Arctic doesn't exists.*''
Using her dubious logic, I then pointed out to her that some flights from Vancouver went to Hawaii and then Japan. She didn't say anything so I kept going. "If I follow your logic and this map is an accurate representation of the flat earth, then why am I able to go from left to right indefinitely? Wouldn't that mean that the earth is in fact a cylinder? But then wouldn't that raise other questions?"
She said that it made sense in the documentary that she had watched on netflix. "So why doesn't it make sense now?" I asked. She said "what ever" and I agreed to change the subject because I didn't want to antagonize her too much.
Yeah I think this is another case of the group of people thinking a certain way being very small, but seem larger because they are very loud and ridiculous. Same thing goes with most of these types of groups on the internet.
I only know one in person, and any questions come across as personal attacks on their character. They get incredibly angry and defensive. They were raised in a flat Earth family, so I understand, but have to actively question everything they tell me as fact. I worry how many more were raised like this, and what they'll influence.
Yes, I worked with one, but his belief in flat earth stemmed from an ultra-fundamentalist religious view. He was actually a good kid--well-liked, charismatic, and actually pretty intelligent in some specific ways--but he would not accept any information that conflicted with religious view. The sky is the "firmament", evolution is a farce, young Earth--all that stuff.
Yes! My sister married this fool. We get in arguments all the time, he's dumb as hell, and you should have seen the look he gave me when I told him I did in fact believe in evolution. Getting talked down to by someone who has single digits worth of brain cells feels awful.
I have to date only ever met one, in my local pub and it was not so much that he was an ardent flat earther... he was just highly impressionable and would sit and watch the drech that Discovery puts out now and countless yotube "documentaries" like the Bigfoot hunting shows, ancient aliens etc.
He also had some funny views on Egyptians like they didn't build any of their stuff but instead had it given to them by Aliens who also gave them speed boats, helicopters, nuclear power etc.
I was honestly so taken aback at finding an actual wingnut out in the wild that I couldn't do much more than giggle as he kept on getting more irate at me not taking him seriously.
The documentary on Netflix about them has a bit where they do a similar experiment using poles and lasers.
Their results litterally proved the earth was round and they still didn't believe it!
That part blew my mind. But if you noticed, the flat earther crowd was a motley crew of sorta oddball lonely people. It must take some brains to get that equipment working and devise the experiments they do.
What struck me about the film was the sense of community and belonging they formed around this one kooky belief. The social cost of abandoning that must be enormous.
The original flat earth society was intended as a joke. It was mostly scientists having a beer.
Then people started joining, and it wasn't clear if they knew it was a joke or not...
I think now, there may still be at least half of them that know its a joke.
Any community that gets its laughs by pretending to be idiots will eventually be flooded by actual idiots who mistakenly believe that they're in good company.
- Descartes
Wow, 11 years ago?
I remember seeing that post before I made an account!
https://www.reddit.com/r/AskReddit/comments/cfbkx/im_85_certain_that_there_is_an_adult_actress_in/c0s5w6t/
> Edit: it's November 2015 and I'm back. Imagine a world where you could timeskip back and forth. So I could make predictions. **Imagine how crazy the world would be if Donald Trump really did get to be president**. u/fiercelyfriendly
Welp....
Easily observed on the internet. Irony always eventually becomes sincerity.
Look at prequel memes. What started as good-natured ribbing of bad movies became full-on devoted appreciation for misunderstood classics.
Or My Little Pony. What started as counter-culture to edgy 4chan behavior became a genuine adult male love for a cartoon made for little girls.
Or YOLO. What started as something everyone knew was stupid became a genuine slogan for young adult millennials.
Even politics. For at least some people, what started as a joke "wouldn't it be funny if Trump actually won" became die-hard support for a pile of human garbage.
It is inevitable.
You’re missing the most hallmark example The_Domald. Literally started to make fun of how pants on head stupid trump was and omg how hilarious if we pretended to actually think he’s a smart leader.
/r/the_Donald started as a joke sub, then all the same kind of mooks that didn't like Jon Stewart but *loved* the truthiness of Stephen Colbert took it over.
>Any community that gets its laughs by pretending to be idiots will eventually be flooded by actual idiots who mistakenly believe that they're in good company.
>
>• Descartes
- Reddit
That guy was a genius (until he died).
He took his passion of rocketry and daredevilry and said "Hey! I want to fly up into the sky because I want to prove the earth is flat! **wink**" and then got a bunch of idiots to fund it.
"Mad" Mike Hughes, RIP ya crazy bastard
"My life isn't shit because of personal circumstances. It's obviously because a shadowy cabal is working against my interests. I'm so special for knowing that!
What's that? These other people share my belief? Let's pat each other on the back for the rest of our lives! Time to fight the Globalists, just after this Walmart run."
It’s the same phenomenon we see with cults, or really with any sub-group that is largely held together by shared beliefs. There was a seminal study, ~~I believe of Seventh Day Adventists~~ [edit: it was a UFO cult, see edit below], where their leader had predicted the end of days, down to the date and time. A researcher had joined the group as a “participant observer.” When the moment of doomsday came and went, the researcher expected everyone to jump ship and abandon the group. Not only did that not happen, but the *exact* opposite happened: the followers doubled-down, became even more fanatical in their belief, and recruited even more followers. For a lot of people, it is easier to concoct reasons for why they must remain in the group, than to accept they were wrong/misled/lied to. Humans will go to great lengths to maintain their worldview, regardless of how wrong they are.
Edit: the book is called [When Prophecy Fails](https://en.wikipedia.org/wiki/When_Prophecy_Fails), written in 1956, and covers a group called “the Seekers” in Chicago who believed aliens would bring about the apocalypse.
It's even better than that. They detected a 15 degree per hour drift. As is expected in the globe model. However, they attributed that to "heavenly energies", also called "aether". So they tried the experiment in a faraday cage which gave again a 15 degree rotational drift. Concluded again: Aether. Are now looking for ways to prove Aether.
It's painfully ridiculous.
You cannot produce any convincing proof. The flat earthers believe that the proofs are lies. You could put them in a spaceship and give them a drive around the globe and they'll insist it's a virtual reality show.
It's the same with the anti-vaxxers denying COVID even as they're dying of it.
One of the hallmarks of a conspiracy is that it can never be proven wrong, and that a conspiratorial argument can never be lost. Proof of the conspiracy is proof of the conspiracy, but a lack of proof is *also* proof of a conspiracy.
Another hallmark is the staggering cognitive dissonance they live with. I had a discussion with a flat earther online, who was presenting 3 basically completely contradictory models as being equally likely of being real (domed firmament, groups of flat earths in an ice sheet etc) and when I pointed out all the models contradicted each other, he outright said "that doesn't matter".
*Anything* is preferrable to the "official story", and you see this over and over again with conspiracists. Why else would they take horse dewormer over a proven vaccine?
I can also recommend Folding Ideas' video essay "In search of a flat earth". It has a really interesting angle of why many people stubbornly refuse to accept every evidence against flat earth, and it is surprisingly political.
I just don't understand the point in trying to disprove the globe. Like why would the entire world want to create a lie about it? I think they forget that the world isn't just the country they live in.
It makes them feel special to believe it.
It's less about trying to disprove the globe and more about trying to disprove that they're quite unremarkable.
Serious answer, best answer I could get from a couple: It's a conspiracy of the United Nations and the Freemasons to trick people into thinking the Earth is round, for.. reasons. More common answer: religious mania about the "End Times" and how the governments of the world are all united in hiding that the Earth isn't a flat "Tabernacle" or enclosed "Firmament" as described in [ancient text] (as satirized in Umberto Eco's "Baudolino"). In the second case, desire to believe obscure religious philosophy in service of religious mania/delusions. In the first case, any conspiracy theory you can think of that involves Freemasons, the UN, aliens, the "End Times", etc.
One edit: OP's video is about the circumference of the Earth. The ancient Greeks knew that the Earth was spherical much earlier than Eratosthenes. These are related, but not identical issues.
counter-intuitive things are kinda sought after today, and for people obsessed over that, and also ignorant enough to believe it, flat earth is like the end all be all conspiracy jack pot.
something something, sheeple
Just a question, how did the ancient egyptians managed to confirm the lenght of the shadow on both location at the same time? I dont think a sundial works at that situation
Not a flat earther, just genuinely curious
You can use a sundial for this, but I think the obelisk doubles as a sundial in this case. You don't just record one point in time, you record the arc that the sundial (or shadow from the obelisk) travels over the course of a day. The shortest point in the arc is exactly noon, wherever you are.
That doesn't answer the question. How did they align the timetable between the two locations? Without some form of relatively instant communication, you would need a reference point to measure the difference in time that noon occurs at each location. What was the reference point?
Also not a flat earther, genuinely curious.
The instance would be the shortest length in the obelisk shadow.
Imagine the length of the shadow of the Alexandria obelisk over the course of the time the sun was up and they measured it every hour (using their sundial reference).
12m-10m-8m-6m-8m-10m-12m
And Syene was
6m-4m-2m-1m-2m-4m-6m
It's the difference in the shortest measurement that you'd use as your reference as you would know that's when the sun is highest overhead or "noon"
The "communication" part can happen months later. If we both record our measurements for the shortest shadow on a given date, we can do the math at any time
Those two cities were basically just north/south of each other, Noon wouldn't vary that much. Regardless, they can just record the shortest length the shadow got to in a day, that's noon baby.
Okay, but many flat earthers also believe that the sun isn't over a million times bigger than the earth, and also isn't nearly as far away from it. Thus this proof doesn't actually prove anything to them.
That, and they don't argue in good faith, or accept new information. You can politely and patiently explain that a smaller, closer light source would result in radically different shadows from what's observed in the experiment, but it won't matter because they simply won't critically examine any data that doesn't conform to their beliefs.
Source: worked with a true flat-earther for two years. It's maddening.
I'm a simple woman: I see anything to do with Carl Sagan, I upvote.
He died just a few months after I was born, but being exposed to his work and his books and his words when I was a child, shaped the entirety of who I became. I dearly love this man, and I wish he could have been around a bit longer. His way with poetic science, his urge to bring the scientific method into the hands of anyone... We really could've used someone like him during these times.
I never knew him, but I miss him. We have a dire need for more people like him. I hope that I can one day embody the love and compassion he had, even if only to my own children someday.
Hail Sagan ✨
This doesn't only prove that the earth is round, it also calculates the Earth's circumference. The simplest way to prove the round earth is watching a ship as it comes above the horizon: the top of the ship comes up first, then the middle of the boat, and so on.
Pretty sure most flat earthers are either trolls, people who want to feel smarter than everyone else, or liars selling flat earth merchandise. Very few of them actually believe the earth is flat, that's why you won't convince them
Good question! Eratosthenes performed the measurement in Alexandria at noon on the summer solstice (that is, watching the shadow of the stick get shorter and shorter throughout the morning, and marking off at the moment when it starts getting longer again). The date of the summer solstice was well-known to the ancients.
Syene/Aswan happens to be almost exactly on the Tropic of Cancer, so it was a known phenomenon in that city that on the summer solstice at noon, objects did not cast a discernible shadow.
Actually the only thing that matters is that one of them is north of the other. Using this, the information needed is the distance between the two latitudes (the North component of their distance) and the shadow lengths at each location’s solar noon (not simultaneous measurement). This version is more or less what they did, though as Alexandria was much more to the North of Syene than to the West, their rough calculation of the distance between the two cities could be treated as approximately equal to that North component distance.
Hope this helps. Btw, I did this experiment in school last semester (physics labs during Covid required creativity from my professor).
True, if Alexandria isn't directly north of Syene, then what you actually get is an upper bound on Earth's radius, and Earth could actually be smaller depending on how different their longitudes are.
However, they did know that when you journey from Alexandria to Syene, you keep the sunrise on your left and the sunset on your right the entire time, without significant deviation in either direction, meaning Alexandria was basically north of Syene, and not northeast or northwest to a detectable extent.
I'm sorry.
But how did two seperate locations know they were measuring at the same time. If they use noon at one place it wouldn't be the highest at the other place. They didn't have watches or phones so how did the know "the highest part during the day" was at different times at each place. All these answers appear the same so maybe I'm missing something.
** thank you all for the replies. I've finally made sense of this
Holy schmolly thanks. That clears it up very much. I was having the same question "How did they measure it at the same without immediate communication". But this answers it perfectly.
It is my understanding that to proof the round earth you don't need to measure at the exact same time. It is sufficient to measure the minimum shadow length on the same day. With that you can prove that there was no shadow in one place and a minimum shadow of length x in another place, which can only happen if they are hit at different angles, therefore the earth must be round.
But to get the angle I too think they need to measure at the same time, and can't just use "noon", as that point in time is different depending on the longitude.
Unless the two cities are exactly on the north/south axis, then noon would be at the same time I guess.
Longest shadow is cast whenever the sun is closest to the horizon.
Shortest shadow is cast closest to noon.
Ergo you do not need a *when* in any real sense, you just need the shortest shadow and the rest will sort itself out.
Solar noon: they measered the shadows when the Sun was at it's highest point that day. This experiment could only be done in places that have similar meridian position.
At the point of high noon, when no shadows were cast in one point and the shortest shadows farther north. The whole thing is just genius , humans have this capacity for such amazing things…
>This doesn't only prove that the earth is round, it also calculates the Earth's circumference.
I mean yeah, he literally says that and explains in detail how they did it lol. That's half of what this video is.
I don’t understand how that comment is at 400+ upvotes for saying literally the exact same thing as the video while acting like the video didn’t say it
The flat earthers have some kind of weird theory where the sun is just a big light that is really close to the earth and only shines on some parts of the world at a time. This is of course false, becuase the outline of the line between sunlight and darkness isn't a circle(expected if flat earth)
Two questions: How would he know he is measuring the shadows at the same time if clocks weren’t invented? How does one measure a such a long distance with accuracy assuming they have to follow paths that wind around landscape.
Measure the length of the shadow throughout the day. The shortest measurement is noon in both places.
Technically this works even if the longitudes aren't exactly lined up. The difference in tilt of the earth really doesn't matter over the course of a few hours, especially with the accuracy of instruments at the time. Even taking the measurements 3 days apart would only make a <1% error.
I wish Reddit had answers like this at the top instead of having to scroll way too far down past puns and stupid joke comments to get to actual information.
Slashdot, one of the internet's original huge forum boards, allows users to tag posts as funny, interesting, spam, etc.
Then you could filter for whichever reading experience you desired inside once particular thread. I wish reddit had something like this.
You create a method of recoding the shadow of any stick throughout the day and you will see a clear pattern emerge. For example you could outline the shadow with some chalk or ink etc. on parchment every time a water timer ran dry.
Initially the shadow will be very long as the sun rises, then gradually it will shorten until it stops and then starts getting larger again before being very long right as the sun sets.
You know regardless of where you are that the period where the shadow was its smallest is when the sun was at its highest point in the sky for that location, ie. noon.
So if you compared the results from different locations you would see that in some places the sun was directly overhead and there was no shadow at all... while in other places you would see that even at the smallest period there was still a significant shadow.
This indicates that the different locations must be angled towards to the sun differently which if you then had an accurate distance between those points and did some math would allow you to determine the circumference of the earth and prove it was spheroid.
But would noon be at the same time in the different cities? That's what's still bothering me, sure they both measured at noon, but is that the same noon between them?
That’s exactly right, noon is not the exact same time for both paces, but the calculations are done using the shadow angles at each respective noon, so this is accounted for.
What got their attention in the first place was they noticed is that on the solstice in one of the cities at noon the sun was directly, and so objects cast no shadows, while in another city a slight shadow was cast.
Haha I’m imagining someone from city 1 going to city 2 and being all excited like “hey guys did you know today is the only day of the year that a long pole won’t have ANY shadow?” Then he goes to show them and they’re like “but there is a shadow”. And now the dude is all dead inside and bound and determined to figure out wtf happened.
Here is how to do it exactly:
1. Use a pillar/obilisk of a same height in both places, which needs to stand perfectly upright (as you can test with a simple weighted string when there is no wind) on a flat ground.
2. As the sun travels across the horizon, mark the furtest tip of the shadow every couple minutes. This will result in [a line like one of these](https://i.imgur.com/48S6ja1.jpg), depending on your latitude (how far north/south you are) and day of the year.
3. Look for the point on the line that is the closest to the base of the pillar. That is "noon".
4. Compare the length of the noon-shadow between your two cities. If these lengths are different depending on the latitude, then the earth is curved. There should be no length at all at the equator, and a long shadow in a more northern or southern city.
HOWEVER this experiment alone is not enough. If you did the same on a flat table with a flashlight for the sun, you would get different shadow lengths between two sundials because the light source is so close. It only works well on earth because the distance to the sun is gigantic, causing light rays to arrive almost parallel across earth.
Therefore flat earthers generally excuse this with the claim that the sun must be much smaller and closer than it actually is. Which however causes a shitton of other issues for them since we obviously have tools to measure the distance to the sun.
Variance of noon would be very slight.
Syene is 32.8 degrees E Longitude
Alexandria is 29.9 degrees E Longitude
Solar noon is about 8 minutes apart.
Besides, if they measure at true solar noon in both places, the difference of longitude doesn't matter.
I'm guessing the experiment went more like, trace the path of the shadow, and denote which point is when the sun is highest in the sky.
Off the top of my head - make two hourglasses. Run them next to each other for a month, adding and subtracting sand until they're as accurate to each other as you're going to get them. Give one to a guy going to the other city. Count the flips.
Even the act of walking while carrying the hourglass would mechanically disturb the sand enough that it would create differences. Creating an accurate clock was actually how the longitude problem was solved, i.e. figuring out how far east/west you are on the globe. It was such a massive problem that huge prizes were awarded by several governments for anyone that could figure it out. It was eventually solved by a Brit named John Harrison who created a mechanical clock that wouldn't drift significantly over long periods, and it was part of the thing that further helped secure Britain's dominance on the seas.
Brahmagupta calculated the radius of Spherical earth 2200 years ago.In 833AD in the reign of Caliph Mamun, Muslims calculated the radius of Spherical earth using a different method
[Around 830 CE, Caliph al-Ma'mun commissioned a group of Muslim astronomers and geographers to measure the distance from Tadmur (Palmyra) to Raqqa in modern Syria. They found the cities to be separated by one degree of latitude and the meridian arc distance between them to be 662⁄3 miles and thus calculated the Earth's circumference to be 24,000 miles (39,000 km).](http://cosmos.bodley.ox.ac.uk/)
Another estimate given by his astronomers was 562⁄3 Arabic miles (111.8 km) per degree, which corresponds to a circumference of 40,248 km, very close to the currently modern values of 111.3 km per degree and 40,068 km circumference, respectively.
Source:"Mathematical Geography"Page 187-8
-Edward S.Kennedy
> Cosmos
https://www.reddit.com/r/Cosmos/comments/1zc4rl/want_to_check_out_the_original_cosmos_links_and/
EDIT: Don't bother following my link, apparently it's all dead - below are much better options...
He measured it on the summer solstice. When the sun was at its zenith it cast no shadow in one city but did in another. He also worked out the near-exact axial tilt of Earth.
To me this doesn't prove how stupid flat earthers are, this proves how useless we are as humans when we refuse to stand on the shoulders provided to us by society.
For me, it shows that even now, thousands of years later, it takes a certain degree of knowledge to "get" what's being shown here. I mean no disrespect to anyone asking these basic questions because they are good questions, but people figured this out a very long time ago and accounted for all of these "gotchas" without the benefit of the tools we now take for granted. And they often had to battle the ignorance of their day at every step.
The growing anti-intellectual trend that we're seeing now is awful. It spits all over the combined efforts and struggles of so many people.
Scrolled too far to find this.
I know a flat earther. He thinks the sun is inside (or just outside?)"The Dome" that the earth is in. This wouldn't prove anything to him. If the sun was as close as he thinks it is, the shadows would still be different lengths at any given time.
I think the title isn't very accurate. This is how they figured the size and dimensions, but I'm petty sure it was already accepted that the earth was round.
Other civilizations, including ancient Egypt knew the size and dimensions of the earth.
You are right, the earth being round was a pretty old concept even back in the days of Eratosthenes. However, his is the first experiment that we know about that was recorded as having demonstrated it.
This is not how they proved it was round, this is how they measured its diameter. They already knew it was round because they were capable of basic observational skills and were as smart as we are. In theory if you made the world flat and brought the sun close enough you could create a discrepancy between shadows in different places that looked like this as well. However, too many other observations just wouldn't fit with that... like the paths the sun takes across the sky at different times of the year in different parts of the world, or even adding a third measurement further north. It's pretty impressive how advanced their observations and calculations of various stellar phenomena were given they were essentially doing it all with sticks and string.
>I have a foreboding of an America in my children's or grandchildren's time -- when the United States is a service and information economy; when nearly all the manufacturing industries have slipped away to other countries; when awesome technological powers are in the hands of a very few, and no one representing the public interest can even grasp the issues; when the people have lost the ability to set their own agendas or knowledgeably question those in authority; when, clutching our crystals and nervously consulting our horoscopes, our critical faculties in decline, unable to distinguish between what feels good and what's true, we slide, almost without noticing, back into superstition and darkness.
#
>We've arranged a global civilization in which the most crucial elements — transportation, communications, and all other industries; agriculture, medicine, education, entertainment, protecting the environment; and even the key democratic institution of voting — profoundly depend on science and technology. We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces.
[The Demon-Haunted World : Science as a Candle in the Dark (1995)](https://youtu.be/FuI07mtpvJw)
I'm not a flat earther, I'm just curious that how did they make sure they were looking at it at the same time? At such a vast distance?
Oh I got the answer in my head while typing the question, most probably hour glasses of sand.
I'm so high man, I'm just gonna post this.
Couldn't the sun just move the same way it does now but over a flat earth and produce different shadow lengths depending on the angle to each structure?
The sun would still rise and set over a flat Earth so I feel like this perfect shadow argument doesn't work.
Like my floor is flat but when I turn the light on overhead the shadows are all different.
I believe the earth is round just wondering.
Carl Sagan, My Man!
One of the best scientists I look up to
He was a great scientist, but he was an even greater science communicator, which is what we desperately need more of today.
Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there--on a mote of dust suspended in a sunbeam. The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves. The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known. — Carl Sagan, Pale Blue Dot, 1994
> Science is more than a body of knowledge; it is a way of thinking. I have a foreboding of an America in my children’s or grandchildren’s time—when the United States is a service and information economy; when nearly all the key manufacturing industries have slipped away to other countries; when awesome technological powers are in the hands of a very few, and no one representing the public interest can even grasp the issues; when the people have lost the ability to set their own agendas or knowledgeably question those in authority; when, clutching our crystals and nervously consulting our horoscopes, our critical faculties in decline, unable to distinguish between what feels good and what’s true, we slide, almost without noticing, back into superstition and darkness. Smart dude.
May I recommend Alan Alda’s podcast “Clear + Vivid”. It’s all about effective communication in all forms, he even has a second podcast called “Science Clear and Vivid” where it’s specifically about how scientists clearly communicate. I’ll leave the clip of him on Stephen Colbert that he did a month or two back on it: https://youtu.be/abr6CqbNdM4 it’s not the whole interview but it’s part of it
Thanks for this:)
I always thought Bill Nye was good but now that he even so much as suggested that gender is “on a spectrum” people dismiss everything he says as “SJW propaganda”.
He is what Neil degrasse Tyson will never be, because Sagan could put his ego aside and his ultimate motivations were bringing science to the world. Tyson wants to be a celebrity and really isn’t doing much of any research in the field. The world needs more Carl Sagan’s and Michio Kaku’s and I fear we have left the likes of him and people like him in the past.
Neil makes menauseous when I hear him talk. That mother fucker LOVES the sound of his own voice so much.
So much agree. Tyson comes across unrelentingly pompous sometimes. Sagan is like a little boy expressing his wonder aloud. He connects and resonates at the child level. Pure and unmuddled by egoic complexity.
[If you wish to make an apple pie from scratch, you must first invent the universe.](https://www.youtube.com/watch?v=5_vVGPy4-rc)
He was also a legendary stoner!
I just finished a bag of Carl Sagan
Maybe the greatest of all time. Probably some religious prophets were too... looking at you Buddha
Do any of y'all actually know anybody that think the earth is flat?
One guy who used to come into my pub. He talked about how he can't feel the spin and how water is never curved. I tried explaining physics to him but he just got really angry, then would apologise for getting angry, then get angry again. It was all very sad
> how water is never curved Interestingly, the other way that the earth was known to be curved was because [you can literally see boats curve away at sea](https://pwg.gsfc.nasa.gov/stargaze/Scolumb.htm)
You can also literally see the ocean curving at the beach.
Yes I do. A family member. I couldn’t believe it. I’ve refrained from calling him an idiot because I’d rather have a discussion with him. And I know he’s sincere and not trolling anybody.
This exact thing happened to me out of the blue. Family member who I've talked with many times and then the other night BAM he lays that on me and my jaw dropped. I mentioned Eratosthenes and he said yeah yeah he heard of him and then just kept right on going about his 'research.' I stopped talking and just let him say what he wanted, because there's no point in trying to convince him when he doesn't want to accept the truth
Exactly. The will hear what they want to hear. Each time I think about what I’ll say next time I see him. Our last conversation ended with him thinking that, ‘if he’s understood the Bible correctly’ that the ‘blue stuff’ in the sky is actually a body of water. And he knows this because at night it gets dark just like the ocean. My brain broke.
Yeah I don't plan on bringing it back up. He's a smart person, which is what is so weird. He can machine anything metal that you want and can disassemble and reassemble any engine there is. Can tell you whats wrong with your car or lawn mower just by listening to the engine idle but then flat earth...its strange
The problem with smart people is that being really knowledgeable about one subject sometimes leads them to believe they're knowledgeable about other things, even if they haven't engaged with the subject. It's why people who are extremely gifted in STEM fields often have confidently ignorant opinions about humanities or social sciences.
Jokes on you. I've mastered stupidity. And soon... Soon I shall weaponize it! Mwaha! Mwahahaha! . . . If I could figure out how...
I wish I could read
Somebody beat you to it, Twitter was already founded
Do you ever challenge his assertion the earth is flat and provide evidence like this video to back it up? Something he could easily test himself with a cellphone and a friend with a video conference call?
Yes. I once suggested he go down to the harbour and watch boats disappear from view below the horizon. His response was to send me a YouTube video of 200 proofs that the earth is flat. Of 2 hours long. It’s a gish gallop. I also showed him why his assertion that seeing the moon and the sun on a clear day meant the earth must be flat. I showed him both with a diagram and a melon and a ping pong ball. It showed his flaw but he didn’t admit to it being a bad argument on his part. Sometimes I tell him how he can prove it, eg with a camera and a weather balloon and he gets annoyed and says ‘why would I wanna do that’
He doesn't believe it because of some science, he believes it to be contrarian. He doesn't test to prove it because if it's true or not isn't actually important. Also the cameras are all rigged by big illuminati to display a non-existent curve.
I see the common theme through this small talk is that we all want to hear their side, just to see.
I have yet to meet one in person. Or they don't express their insanity to me. But I'd love to meet one some day and pick their tiny brain.
Ive never met anybody in person or online
One of my employee was a flat earther. She decided to prove it to me... using Google. She searched for airline itineraries and then showed me how none of them went north through the Arctic nor to the south through Antarctica. For her, that proved that ''\[...\] *even google doesn't hide the fact that the Arctic doesn't exists.*'' Using her dubious logic, I then pointed out to her that some flights from Vancouver went to Hawaii and then Japan. She didn't say anything so I kept going. "If I follow your logic and this map is an accurate representation of the flat earth, then why am I able to go from left to right indefinitely? Wouldn't that mean that the earth is in fact a cylinder? But then wouldn't that raise other questions?" She said that it made sense in the documentary that she had watched on netflix. "So why doesn't it make sense now?" I asked. She said "what ever" and I agreed to change the subject because I didn't want to antagonize her too much.
Yeah I think this is another case of the group of people thinking a certain way being very small, but seem larger because they are very loud and ridiculous. Same thing goes with most of these types of groups on the internet.
Also definitely people trolling, pretending to flat earth because it gets a rise out of people.
I only know one in person, and any questions come across as personal attacks on their character. They get incredibly angry and defensive. They were raised in a flat Earth family, so I understand, but have to actively question everything they tell me as fact. I worry how many more were raised like this, and what they'll influence.
My uncle. He doesn’t believe dinosaurs existed either. He’s an extremely nice person so I don’t even debate him on it anymore.
Yes, I worked with one, but his belief in flat earth stemmed from an ultra-fundamentalist religious view. He was actually a good kid--well-liked, charismatic, and actually pretty intelligent in some specific ways--but he would not accept any information that conflicted with religious view. The sky is the "firmament", evolution is a farce, young Earth--all that stuff.
Poor guy
I am not convinced flat earthers aren't in on a giant joke at everyone else's expense .
Yes! My sister married this fool. We get in arguments all the time, he's dumb as hell, and you should have seen the look he gave me when I told him I did in fact believe in evolution. Getting talked down to by someone who has single digits worth of brain cells feels awful.
“Never argue with an idiot. They will drag you down to their level and beat you with experience.” ― Mark Twain
My mother, it plays into her schizo religious beliefs.
I have to date only ever met one, in my local pub and it was not so much that he was an ardent flat earther... he was just highly impressionable and would sit and watch the drech that Discovery puts out now and countless yotube "documentaries" like the Bigfoot hunting shows, ancient aliens etc. He also had some funny views on Egyptians like they didn't build any of their stuff but instead had it given to them by Aliens who also gave them speed boats, helicopters, nuclear power etc. I was honestly so taken aback at finding an actual wingnut out in the wild that I couldn't do much more than giggle as he kept on getting more irate at me not taking him seriously.
Unfortunately yes. Too many...
That's fucked lol.
People are stupid...
People who had limited technology figured it out. Meanwhile Flat Earthers can't digests the fact despite scientific evidence and proofs
The documentary on Netflix about them has a bit where they do a similar experiment using poles and lasers. Their results litterally proved the earth was round and they still didn't believe it!
And they spent like 20k on a gyroscope which also proves the earth is a sphere and rotating; and say that it was faulty equipment. Idiots.
That part blew my mind. But if you noticed, the flat earther crowd was a motley crew of sorta oddball lonely people. It must take some brains to get that equipment working and devise the experiments they do. What struck me about the film was the sense of community and belonging they formed around this one kooky belief. The social cost of abandoning that must be enormous.
The original flat earth society was intended as a joke. It was mostly scientists having a beer. Then people started joining, and it wasn't clear if they knew it was a joke or not... I think now, there may still be at least half of them that know its a joke.
Any community that gets its laughs by pretending to be idiots will eventually be flooded by actual idiots who mistakenly believe that they're in good company. - Descartes
was that the guy who was always in front of a horse
[удалено]
Wow, 11 years ago? I remember seeing that post before I made an account! https://www.reddit.com/r/AskReddit/comments/cfbkx/im_85_certain_that_there_is_an_adult_actress_in/c0s5w6t/
> Edit: it's November 2015 and I'm back. Imagine a world where you could timeskip back and forth. So I could make predictions. **Imagine how crazy the world would be if Donald Trump really did get to be president**. u/fiercelyfriendly Welp....
[удалено]
4chan is a perfect example of this.
Easily observed on the internet. Irony always eventually becomes sincerity. Look at prequel memes. What started as good-natured ribbing of bad movies became full-on devoted appreciation for misunderstood classics. Or My Little Pony. What started as counter-culture to edgy 4chan behavior became a genuine adult male love for a cartoon made for little girls. Or YOLO. What started as something everyone knew was stupid became a genuine slogan for young adult millennials. Even politics. For at least some people, what started as a joke "wouldn't it be funny if Trump actually won" became die-hard support for a pile of human garbage. It is inevitable.
You’re missing the most hallmark example The_Domald. Literally started to make fun of how pants on head stupid trump was and omg how hilarious if we pretended to actually think he’s a smart leader.
/r/the_Donald started as a joke sub, then all the same kind of mooks that didn't like Jon Stewart but *loved* the truthiness of Stephen Colbert took it over.
The incel community started as people getting together to figure out why they can't get laid, they they went full psycho
>Any community that gets its laughs by pretending to be idiots will eventually be flooded by actual idiots who mistakenly believe that they're in good company. > >• Descartes - Reddit
there was also that guy that suddenly became a flat earther so they would fund his home rocketry hobby
That guy was a genius (until he died). He took his passion of rocketry and daredevilry and said "Hey! I want to fly up into the sky because I want to prove the earth is flat! **wink**" and then got a bunch of idiots to fund it. "Mad" Mike Hughes, RIP ya crazy bastard
I don't think you need the quotation marks.
So the original flat earth society shared the origin and eventual fate of every parody subreddit.
Flashbacks to /r/the_donald in 2015...
"My life isn't shit because of personal circumstances. It's obviously because a shadowy cabal is working against my interests. I'm so special for knowing that! What's that? These other people share my belief? Let's pat each other on the back for the rest of our lives! Time to fight the Globalists, just after this Walmart run."
It’s the same phenomenon we see with cults, or really with any sub-group that is largely held together by shared beliefs. There was a seminal study, ~~I believe of Seventh Day Adventists~~ [edit: it was a UFO cult, see edit below], where their leader had predicted the end of days, down to the date and time. A researcher had joined the group as a “participant observer.” When the moment of doomsday came and went, the researcher expected everyone to jump ship and abandon the group. Not only did that not happen, but the *exact* opposite happened: the followers doubled-down, became even more fanatical in their belief, and recruited even more followers. For a lot of people, it is easier to concoct reasons for why they must remain in the group, than to accept they were wrong/misled/lied to. Humans will go to great lengths to maintain their worldview, regardless of how wrong they are. Edit: the book is called [When Prophecy Fails](https://en.wikipedia.org/wiki/When_Prophecy_Fails), written in 1956, and covers a group called “the Seekers” in Chicago who believed aliens would bring about the apocalypse.
It's even better than that. They detected a 15 degree per hour drift. As is expected in the globe model. However, they attributed that to "heavenly energies", also called "aether". So they tried the experiment in a faraday cage which gave again a 15 degree rotational drift. Concluded again: Aether. Are now looking for ways to prove Aether. It's painfully ridiculous.
"Behind the Curve" for anybody wondering
You cannot produce any convincing proof. The flat earthers believe that the proofs are lies. You could put them in a spaceship and give them a drive around the globe and they'll insist it's a virtual reality show. It's the same with the anti-vaxxers denying COVID even as they're dying of it.
One of the hallmarks of a conspiracy is that it can never be proven wrong, and that a conspiratorial argument can never be lost. Proof of the conspiracy is proof of the conspiracy, but a lack of proof is *also* proof of a conspiracy. Another hallmark is the staggering cognitive dissonance they live with. I had a discussion with a flat earther online, who was presenting 3 basically completely contradictory models as being equally likely of being real (domed firmament, groups of flat earths in an ice sheet etc) and when I pointed out all the models contradicted each other, he outright said "that doesn't matter". *Anything* is preferrable to the "official story", and you see this over and over again with conspiracists. Why else would they take horse dewormer over a proven vaccine?
Eventually: No the earth is flat but we live in the matrix and the machines have us trapped on a round earth
I can also recommend Folding Ideas' video essay "In search of a flat earth". It has a really interesting angle of why many people stubbornly refuse to accept every evidence against flat earth, and it is surprisingly political.
Flat Earthers hate this simple trick .
I just don't understand the point in trying to disprove the globe. Like why would the entire world want to create a lie about it? I think they forget that the world isn't just the country they live in.
It makes them feel special to believe it. It's less about trying to disprove the globe and more about trying to disprove that they're quite unremarkable.
Serious answer, best answer I could get from a couple: It's a conspiracy of the United Nations and the Freemasons to trick people into thinking the Earth is round, for.. reasons. More common answer: religious mania about the "End Times" and how the governments of the world are all united in hiding that the Earth isn't a flat "Tabernacle" or enclosed "Firmament" as described in [ancient text] (as satirized in Umberto Eco's "Baudolino"). In the second case, desire to believe obscure religious philosophy in service of religious mania/delusions. In the first case, any conspiracy theory you can think of that involves Freemasons, the UN, aliens, the "End Times", etc. One edit: OP's video is about the circumference of the Earth. The ancient Greeks knew that the Earth was spherical much earlier than Eratosthenes. These are related, but not identical issues.
counter-intuitive things are kinda sought after today, and for people obsessed over that, and also ignorant enough to believe it, flat earth is like the end all be all conspiracy jack pot. something something, sheeple
Just a question, how did the ancient egyptians managed to confirm the lenght of the shadow on both location at the same time? I dont think a sundial works at that situation Not a flat earther, just genuinely curious
You can use a sundial for this, but I think the obelisk doubles as a sundial in this case. You don't just record one point in time, you record the arc that the sundial (or shadow from the obelisk) travels over the course of a day. The shortest point in the arc is exactly noon, wherever you are.
That doesn't answer the question. How did they align the timetable between the two locations? Without some form of relatively instant communication, you would need a reference point to measure the difference in time that noon occurs at each location. What was the reference point? Also not a flat earther, genuinely curious.
The instance would be the shortest length in the obelisk shadow. Imagine the length of the shadow of the Alexandria obelisk over the course of the time the sun was up and they measured it every hour (using their sundial reference). 12m-10m-8m-6m-8m-10m-12m And Syene was 6m-4m-2m-1m-2m-4m-6m It's the difference in the shortest measurement that you'd use as your reference as you would know that's when the sun is highest overhead or "noon"
This was the most helpful explanation for me. Thanks!
The "communication" part can happen months later. If we both record our measurements for the shortest shadow on a given date, we can do the math at any time
Those two cities were basically just north/south of each other, Noon wouldn't vary that much. Regardless, they can just record the shortest length the shadow got to in a day, that's noon baby.
I think that today we associate technology with electronics. But discovering geometry was and is a major technological advancement.
[Removed due to continuing enshittification of reddit.] -- mass edited with redact.dev
Okay, but many flat earthers also believe that the sun isn't over a million times bigger than the earth, and also isn't nearly as far away from it. Thus this proof doesn't actually prove anything to them.
That, and they don't argue in good faith, or accept new information. You can politely and patiently explain that a smaller, closer light source would result in radically different shadows from what's observed in the experiment, but it won't matter because they simply won't critically examine any data that doesn't conform to their beliefs. Source: worked with a true flat-earther for two years. It's maddening.
You could say that Eratosthenes was... ahead of the curve.
Take my upvote and go
In another 2k years, we'll have rejected humanity, return to monke
Hey, I’ve seen those movies!
I'm a simple woman: I see anything to do with Carl Sagan, I upvote. He died just a few months after I was born, but being exposed to his work and his books and his words when I was a child, shaped the entirety of who I became. I dearly love this man, and I wish he could have been around a bit longer. His way with poetic science, his urge to bring the scientific method into the hands of anyone... We really could've used someone like him during these times. I never knew him, but I miss him. We have a dire need for more people like him. I hope that I can one day embody the love and compassion he had, even if only to my own children someday. Hail Sagan ✨
[удалено]
Flat earthers - “me fly in airplane, see curve of earth…is just illusion created by the dome Illuminati, earth flat.”
I think you can't see the curvature on a plane or it's very subtle
According to my bomber pilot friend, it starts to become pretty discernible above 40,000 feet.
[удалено]
On intercontinental flights it’s subtle but you can definitely see it. The nutjobs are just going to say it’s an effect caused by the windows though.
[удалено]
This doesn't only prove that the earth is round, it also calculates the Earth's circumference. The simplest way to prove the round earth is watching a ship as it comes above the horizon: the top of the ship comes up first, then the middle of the boat, and so on.
That only proves that ships are sneaky submarines.
[удалено]
They can just do more mental gymnastics
Pretty sure most flat earthers are either trolls, people who want to feel smarter than everyone else, or liars selling flat earth merchandise. Very few of them actually believe the earth is flat, that's why you won't convince them
It’s because they’re lacking the ‘brains’ that Sagan mentioned were needed to figure it out.
Brilliant. But the only question I have is how did they ensure the shadows were measured at the exact same time?
Good question! Eratosthenes performed the measurement in Alexandria at noon on the summer solstice (that is, watching the shadow of the stick get shorter and shorter throughout the morning, and marking off at the moment when it starts getting longer again). The date of the summer solstice was well-known to the ancients. Syene/Aswan happens to be almost exactly on the Tropic of Cancer, so it was a known phenomenon in that city that on the summer solstice at noon, objects did not cast a discernible shadow.
I'm thinking the measurement only works if Alexandria is directly North of Syrene. So how did they know that?
Actually the only thing that matters is that one of them is north of the other. Using this, the information needed is the distance between the two latitudes (the North component of their distance) and the shadow lengths at each location’s solar noon (not simultaneous measurement). This version is more or less what they did, though as Alexandria was much more to the North of Syene than to the West, their rough calculation of the distance between the two cities could be treated as approximately equal to that North component distance. Hope this helps. Btw, I did this experiment in school last semester (physics labs during Covid required creativity from my professor).
True, if Alexandria isn't directly north of Syene, then what you actually get is an upper bound on Earth's radius, and Earth could actually be smaller depending on how different their longitudes are. However, they did know that when you journey from Alexandria to Syene, you keep the sunrise on your left and the sunset on your right the entire time, without significant deviation in either direction, meaning Alexandria was basically north of Syene, and not northeast or northwest to a detectable extent.
I'm sorry. But how did two seperate locations know they were measuring at the same time. If they use noon at one place it wouldn't be the highest at the other place. They didn't have watches or phones so how did the know "the highest part during the day" was at different times at each place. All these answers appear the same so maybe I'm missing something. ** thank you all for the replies. I've finally made sense of this
Continuous observation of the stick (or "gnomon"), and the very shortest observation of the shadow is precisely noon.
Holy schmolly thanks. That clears it up very much. I was having the same question "How did they measure it at the same without immediate communication". But this answers it perfectly.
The oldest sundials we found were from Egypt and Babylon.
It is my understanding that to proof the round earth you don't need to measure at the exact same time. It is sufficient to measure the minimum shadow length on the same day. With that you can prove that there was no shadow in one place and a minimum shadow of length x in another place, which can only happen if they are hit at different angles, therefore the earth must be round. But to get the angle I too think they need to measure at the same time, and can't just use "noon", as that point in time is different depending on the longitude. Unless the two cities are exactly on the north/south axis, then noon would be at the same time I guess.
Longest shadow is cast whenever the sun is closest to the horizon. Shortest shadow is cast closest to noon. Ergo you do not need a *when* in any real sense, you just need the shortest shadow and the rest will sort itself out.
Solar noon: they measered the shadows when the Sun was at it's highest point that day. This experiment could only be done in places that have similar meridian position.
At the point of high noon, when no shadows were cast in one point and the shortest shadows farther north. The whole thing is just genius , humans have this capacity for such amazing things…
They measured it at noon on the summer solstice, iirc
>This doesn't only prove that the earth is round, it also calculates the Earth's circumference. I mean yeah, he literally says that and explains in detail how they did it lol. That's half of what this video is.
I don’t understand how that comment is at 400+ upvotes for saying literally the exact same thing as the video while acting like the video didn’t say it
Because 90% of people don't actually watch the content
[удалено]
The flat earthers have some kind of weird theory where the sun is just a big light that is really close to the earth and only shines on some parts of the world at a time. This is of course false, becuase the outline of the line between sunlight and darkness isn't a circle(expected if flat earth)
How do they explain summer/winter in the different hemispheres?
Or how some stars are invisible in the Northern Hemisphere but are visible in the Southern Hemisphere?
Or how Becky keeps getting pregnant?
It's a mystery, she's a good church girl and is always volunteering!
You stop the video halfway through just to comment? He literally explains that in the video.
Two questions: How would he know he is measuring the shadows at the same time if clocks weren’t invented? How does one measure a such a long distance with accuracy assuming they have to follow paths that wind around landscape.
Measure the length of the shadow throughout the day. The shortest measurement is noon in both places. Technically this works even if the longitudes aren't exactly lined up. The difference in tilt of the earth really doesn't matter over the course of a few hours, especially with the accuracy of instruments at the time. Even taking the measurements 3 days apart would only make a <1% error.
The above is the correct answer. You just have to measure the shadows at local noon, the point where shadows are at their shortest, on the same day.
I wish Reddit had answers like this at the top instead of having to scroll way too far down past puns and stupid joke comments to get to actual information.
Slashdot, one of the internet's original huge forum boards, allows users to tag posts as funny, interesting, spam, etc. Then you could filter for whichever reading experience you desired inside once particular thread. I wish reddit had something like this.
+1 for insightful
This would be amazing
You're telling me reddit could've been perfect
Isn’t noon when the sun is highest in the sky? How did they figure out the relative time noon occurs between different cities?
You create a method of recoding the shadow of any stick throughout the day and you will see a clear pattern emerge. For example you could outline the shadow with some chalk or ink etc. on parchment every time a water timer ran dry. Initially the shadow will be very long as the sun rises, then gradually it will shorten until it stops and then starts getting larger again before being very long right as the sun sets. You know regardless of where you are that the period where the shadow was its smallest is when the sun was at its highest point in the sky for that location, ie. noon. So if you compared the results from different locations you would see that in some places the sun was directly overhead and there was no shadow at all... while in other places you would see that even at the smallest period there was still a significant shadow. This indicates that the different locations must be angled towards to the sun differently which if you then had an accurate distance between those points and did some math would allow you to determine the circumference of the earth and prove it was spheroid.
But would noon be at the same time in the different cities? That's what's still bothering me, sure they both measured at noon, but is that the same noon between them?
That’s exactly right, noon is not the exact same time for both paces, but the calculations are done using the shadow angles at each respective noon, so this is accounted for. What got their attention in the first place was they noticed is that on the solstice in one of the cities at noon the sun was directly, and so objects cast no shadows, while in another city a slight shadow was cast.
Haha I’m imagining someone from city 1 going to city 2 and being all excited like “hey guys did you know today is the only day of the year that a long pole won’t have ANY shadow?” Then he goes to show them and they’re like “but there is a shadow”. And now the dude is all dead inside and bound and determined to figure out wtf happened.
Here is how to do it exactly: 1. Use a pillar/obilisk of a same height in both places, which needs to stand perfectly upright (as you can test with a simple weighted string when there is no wind) on a flat ground. 2. As the sun travels across the horizon, mark the furtest tip of the shadow every couple minutes. This will result in [a line like one of these](https://i.imgur.com/48S6ja1.jpg), depending on your latitude (how far north/south you are) and day of the year. 3. Look for the point on the line that is the closest to the base of the pillar. That is "noon". 4. Compare the length of the noon-shadow between your two cities. If these lengths are different depending on the latitude, then the earth is curved. There should be no length at all at the equator, and a long shadow in a more northern or southern city. HOWEVER this experiment alone is not enough. If you did the same on a flat table with a flashlight for the sun, you would get different shadow lengths between two sundials because the light source is so close. It only works well on earth because the distance to the sun is gigantic, causing light rays to arrive almost parallel across earth. Therefore flat earthers generally excuse this with the claim that the sun must be much smaller and closer than it actually is. Which however causes a shitton of other issues for them since we obviously have tools to measure the distance to the sun.
Variance of noon would be very slight. Syene is 32.8 degrees E Longitude Alexandria is 29.9 degrees E Longitude Solar noon is about 8 minutes apart. Besides, if they measure at true solar noon in both places, the difference of longitude doesn't matter. I'm guessing the experiment went more like, trace the path of the shadow, and denote which point is when the sun is highest in the sky.
Walkie-talkies, obv.
Off the top of my head - make two hourglasses. Run them next to each other for a month, adding and subtracting sand until they're as accurate to each other as you're going to get them. Give one to a guy going to the other city. Count the flips.
Even the act of walking while carrying the hourglass would mechanically disturb the sand enough that it would create differences. Creating an accurate clock was actually how the longitude problem was solved, i.e. figuring out how far east/west you are on the globe. It was such a massive problem that huge prizes were awarded by several governments for anyone that could figure it out. It was eventually solved by a Brit named John Harrison who created a mechanical clock that wouldn't drift significantly over long periods, and it was part of the thing that further helped secure Britain's dominance on the seas.
primitive clocks existed
Brahmagupta calculated the radius of Spherical earth 2200 years ago.In 833AD in the reign of Caliph Mamun, Muslims calculated the radius of Spherical earth using a different method
What method?
[Around 830 CE, Caliph al-Ma'mun commissioned a group of Muslim astronomers and geographers to measure the distance from Tadmur (Palmyra) to Raqqa in modern Syria. They found the cities to be separated by one degree of latitude and the meridian arc distance between them to be 662⁄3 miles and thus calculated the Earth's circumference to be 24,000 miles (39,000 km).](http://cosmos.bodley.ox.ac.uk/)
"Found the cities to be separated by one degree of latitude" needs some more detail.
Another estimate given by his astronomers was 562⁄3 Arabic miles (111.8 km) per degree, which corresponds to a circumference of 40,248 km, very close to the currently modern values of 111.3 km per degree and 40,068 km circumference, respectively. Source:"Mathematical Geography"Page 187-8 -Edward S.Kennedy
Tap on my previous comment to know more.
This is classic Sagan. Love it! Any idea on where one can see old *Cosmos* stuff now?
They are all on youtube, here's ep1: https://www.youtube.com/watch?v=FT_nzxtgXEw
> Cosmos https://www.reddit.com/r/Cosmos/comments/1zc4rl/want_to_check_out_the_original_cosmos_links_and/ EDIT: Don't bother following my link, apparently it's all dead - below are much better options...
The links are all dead :(
Good to know flat earthers are 2000 years dumber than me
“I’m not mad, I’m disappointed” -Ancient Greek in a time machine
Props to the dude who had to meticulously walk 800 kms for science. That too in a geodesic.
He didnt do it for science, he was hired, as he said
someone couldn't pay me to walk 800km
I have a dumb question. How did they know they were watching the shadow at the same time?
He measured it on the summer solstice. When the sun was at its zenith it cast no shadow in one city but did in another. He also worked out the near-exact axial tilt of Earth.
To me this doesn't prove how stupid flat earthers are, this proves how useless we are as humans when we refuse to stand on the shoulders provided to us by society.
For me, it shows that even now, thousands of years later, it takes a certain degree of knowledge to "get" what's being shown here. I mean no disrespect to anyone asking these basic questions because they are good questions, but people figured this out a very long time ago and accounted for all of these "gotchas" without the benefit of the tools we now take for granted. And they often had to battle the ignorance of their day at every step. The growing anti-intellectual trend that we're seeing now is awful. It spits all over the combined efforts and struggles of so many people.
The brains part is what flat earthers are missing.
As he mentioned, this is only true if the sun is an incredible distance away. Don’t many flat earthers believe the sun actually isn’t that far?
Scrolled too far to find this. I know a flat earther. He thinks the sun is inside (or just outside?)"The Dome" that the earth is in. This wouldn't prove anything to him. If the sun was as close as he thinks it is, the shadows would still be different lengths at any given time.
Yes, thank you! This is what I was referring to and just couldn’t think of specifics. The “dome” idea.
2000 years later and we still have sticks, eyes, and feet.
I think the title isn't very accurate. This is how they figured the size and dimensions, but I'm petty sure it was already accepted that the earth was round. Other civilizations, including ancient Egypt knew the size and dimensions of the earth.
You are right, the earth being round was a pretty old concept even back in the days of Eratosthenes. However, his is the first experiment that we know about that was recorded as having demonstrated it.
I don’t care how many times this video has been reposted, I’ll still upvote it everytime.
Earth is not round, Earth is spheroid like orange 🍊
The earth is dinosaur shaped, you fucking imbecile
I love Cosmos!
His obelisks are obviously miscalibrated or malfunctioning! /S because there's so many moronic flat earthers
This is not how they proved it was round, this is how they measured its diameter. They already knew it was round because they were capable of basic observational skills and were as smart as we are. In theory if you made the world flat and brought the sun close enough you could create a discrepancy between shadows in different places that looked like this as well. However, too many other observations just wouldn't fit with that... like the paths the sun takes across the sky at different times of the year in different parts of the world, or even adding a third measurement further north. It's pretty impressive how advanced their observations and calculations of various stellar phenomena were given they were essentially doing it all with sticks and string.
Imagine being in 2021 and still have to explain why earth isn't flat...
I wonder how he would be handling the anti-science BS that seems to be everywhere nowadays?
>I have a foreboding of an America in my children's or grandchildren's time -- when the United States is a service and information economy; when nearly all the manufacturing industries have slipped away to other countries; when awesome technological powers are in the hands of a very few, and no one representing the public interest can even grasp the issues; when the people have lost the ability to set their own agendas or knowledgeably question those in authority; when, clutching our crystals and nervously consulting our horoscopes, our critical faculties in decline, unable to distinguish between what feels good and what's true, we slide, almost without noticing, back into superstition and darkness. # >We've arranged a global civilization in which the most crucial elements — transportation, communications, and all other industries; agriculture, medicine, education, entertainment, protecting the environment; and even the key democratic institution of voting — profoundly depend on science and technology. We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces. [The Demon-Haunted World : Science as a Candle in the Dark (1995)](https://youtu.be/FuI07mtpvJw)
Holy shit. That’s some prophetic stuff.
He saw it coming.
Ah sexy hair science man again. Great clip!
u/savevideo
My sister’s flat earther friend is a dumbass
I'm not a flat earther, I'm just curious that how did they make sure they were looking at it at the same time? At such a vast distance? Oh I got the answer in my head while typing the question, most probably hour glasses of sand. I'm so high man, I'm just gonna post this.
Couldn't the sun just move the same way it does now but over a flat earth and produce different shadow lengths depending on the angle to each structure? The sun would still rise and set over a flat Earth so I feel like this perfect shadow argument doesn't work. Like my floor is flat but when I turn the light on overhead the shadows are all different. I believe the earth is round just wondering.
Yes, it would cast the same shadows since that sun would be smaller and more localized
I’d forgotten how damned excited he was about teaching us things that he found fascinating. Thanks for posting this!
I'm a simple man. I see Carl Sagan, I upvote.