Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Villi on 26/06/2016 06:46:45
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Most of my limited knowledge from school, media and what everyone says suggests the earth is round. However, I've come across a lot of recent stuff that's tickling my brain and I'm wondering if the earth is flat. What are some experiments I can do to disprove the earth is flat theory?
For example, they say we are in a dome, the sun is a couple thousand miles up and going in a circle above the flat earth map. I'm guessing I need a telescope? I honestly don't feel like spending money or time on this though. Just wondering about what people think.
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This comes up with some regularity as the flat earthers go to very convoluted lengths to provide arguments to 'prove' their case.
Usually we move such discussion to new theories or more properly 'it can't be true'.
Some experiments you can do:
Use a telescope to watch a ship going over the horizon, you will see the bottom part disappears first, superstructure last so the surface of earth is curved.
The curvature can be measured. Put 3 posts in a lake as far apart as possible, so they stick up the same amount above the water, then sight across the tops. You will see the centre post is higher because of the curvature. You can measure this curvature all over the earth and it is roughly the same.
Look at the pole star and measure its elevation (angle to ground). This matches your latitude on a map. If you try to draw out the geometry for the elevation at different latitudes and assume a flat earth it doesn't work, has to be a sphere.
You can do the same with their claim that the sun is only a few thousand miles up, it doesn't work out.
Look at the moon, it's a sphere. No reason to believe earth is not the same.
PS this topic is likely to be moved.
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No need to do any experiments for yourself. Aristarchus and Eratosthenes provided a heliocentric model and measured the diameter of the spherical earth, about 2500 years ago. Their work is widely published in elementary schoolbooks.
If you think things might have changed recently, talk to any surveyor, cartographer, soldier, sailor, pilot or astronaut, and ask them how they get from A to B without using spherical geometry. (The rest of us use numbered roads, so generally have no idea!)
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Just googled it, here is a link
http://www.popsci.com/10-ways-you-can-prove-earth-is-round#
For point #8 in the list, you can prove it yourself easily if you have someone you know on different longitude. You can chat or even make a video call with them and ask them what time is it now.
I'd like to add one more thing to the list. If you are on Northern hemisphere, you will see stars move counterclockwise in circular trajectory around polaris. But if you are on Southern hemisphere, you will see stars move clockwise. This is impossible if only the earth was flat.
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Or you could watch videos made on the ISS and see the earth rotate. There are so many ways to prove the point. I often wonder if the idea of believers in a flat earth in the past was not just a relatively recent urban myth to make our modern day selves feel superior.
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just as I thought ..,.,
https://en.m.wikipedia.org/wiki/Myth_of_the_flat_Earth (https://en.m.wikipedia.org/wiki/Myth_of_the_flat_Earth)
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Or you could watch videos made on the ISS and see the earth rotate. There are so many ways to prove the point. I often wonder if the idea of believers in a flat earth in the past was not just a relatively recent urban myth to make our modern day selves feel superior.
Flat earthers reject videos by saying that videos are not real and can be easily manipulated.
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Apologies if this topic is in the wrong forum. Move as necessary.
So it seems the telescope thing is most accessible to me.
I did some math and for a ship to disappear under 100m of curvature of the 6371km radius earth, it would have to travel 36km. Someone please verify this because math is one of my weakest subjects.
Now I just need to find the right telescope and a way to track a ships movement/distance.
To be clear, I still think the earth is round, but I really want to do something with my own hands to prove it.
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No need for a telescope. Use http://www.ringbell.co.uk/info/hdist.htm (http://www.ringbell.co.uk/info/hdist.htm) to calculate the horizon distance from a given observer height above sea level, then stand on the beach and watch a small boat.
From 2 meters above sea level, the horizon is about 5.1 km, well within unaided visual range on a clear day.
Or try walking along a very long concave curved beach (the Jurassic Coast is excellent, as is Morecambe Bay and several sandy bays in Scotland. At some point you won't be able to see the far end of the beach. Take a friend or child, significantly taller or shorter than yourself, and ask them when the landmark disappears. If the earth were flat, it wouldn't disappear at all, or would disappear at the same distance for both of you if you believe the worst poppycock.
Or try climbing the cliff at one end of the long beach - can you see further than at sea level? Try sitting down - is the horizon closer?
You can compare your measurements with the horizon calculator, which is based on a simple spherical model, or use the tables in Reed's Nautical Almanac (based on a 2 m asl observation point for yachtsmen) or the AOPA Pilot's Manual (if you are very tall!)
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The only thing I would add to what Alan said is that if you are looking at ships it's worth being high enough to avoid wave height confusing the exact point of disappearance.
You might find the following table useful as well as the ref Alan gave (Reed's costs money). http://www.sailtrain.co.uk/navigation/rising.htm
If the subject really interests you a text on astro navigation will be quite enlightening along with some basic astronomy. There is a lot on the web.
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For example, they say we are in a dome, the sun is a couple thousand miles up and going in a circle above the flat earth map. I'm guessing I need a telescope? I honestly don't feel like spending money or time on this though. Just wondering about what people think.
If that were true then the Sun would never set, and yet it does. If that were true then ships on the ocean would never disappear below the horizon, and yet they do. If that were true then the set of stars people in the northern hemisphere would be the same set of stars as the people in the southern hemisphere would see, and yet they aren't. If that were true then distance measurements between locations on the earth would tell us that the earth was flat, and yet they don't. They tell us that the earth is a sphere.
Etc, etc, etc.
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If the Earth were flat, gravity would work in some very weird unknown way.
To answer you question no the Earth in not flat is a roundish Object held in the gravity field of Its star namely our beautiful golden sun that rises in the east and sets in the west precisely because the Earth is round and revolving on its axis!
Alan
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If the Earth were flat, gravity would work in some very weird unknown way.
Actually it's not unknown, but is calculatable. I was thinking of putting the question up.
On a spherical earth the downward pull towards the centre is the resultant of the sum of all the vectors from the distributed mass. That means there is a significant, but small, sideways pull which balances out.
If the earth were flat you would get a much greater sideways pull if you were at the centre of the disc, would that make us wider than we are?? Towards the edge of the disc, the pull would become asymmetric pulling you back towards the centre of the disc. I haven't got the time to do the calculations, anyone fancy a go?
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If the Earth were flat, gravity would work in some very weird unknown way.
Actually it's not unknown, but is calculatable. I was thinking of putting the question up.
On a spherical earth the downward pull towards the centre is the resultant of the sum of all the vectors from the distributed mass. That means there is a significant, but small, sideways pull which balances out.
If the earth were flat you would get a much greater sideways pull if you were at the centre of the disc, would that make us wider than we are?? Towards the edge of the disc, the pull would become asymmetric pulling you back towards the centre of the disc. I haven't got the time to do the calculations, anyone fancy a go?
Let's not forget that if the Earth was flat as they claim it is then the sun would fall down and all the geostationary satellites that are orbiting the earth wouldn't be there. So much for DirectTV, huh? Lol!
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[ Invalid Attachment ] Look at Terry Pratchets Flat Earth/World
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That site verified my math is correct, although it was in reverse and I put in 100m to cover any possible cruise ship. Thanks.
I really need a telescope because I'm very near-sighted. Things may as well not exist beyond a hundred metres for me.
I also don't know squat about astronomy and can't readily view stars from the city I'm in. Nor do I know what light and photons are, so I can't explain why I see the things I do. I know the sun sets and rises east to west. The flat earthers have some interesting ideas and probably unconfirmed facts about all this. That light doesn't go forever and that it bends. The sun goes in a circle in one direction east to west for us. No one's gotten past Antarctica. That what we see as the moon, stars and other planets are holograms on the dome or something. That anything NASA says or gives data about it probes and missions is false. We don't know what gravity is and we are only starting to detect gravitational waves.
I've personally never confirmed anything I was taught about in physics to astronomy. I've only ever flown in planes and have not seen curvature (but I wasn't looking for it) nor have I gone in space to see earth orbiting the sun. Basically all I'm saying is I don't know anything. I at least want to see a boat disappear under the horizon.
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From 2 meters above sea level, the horizon is about 5.1 km, well within unaided visual range on a clear day.
Formally, it can be a result of somekind of atmospheric refraction.
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Or you could watch videos made on the ISS and see the earth rotate. There are so many ways to prove the point. I often wonder if the idea of believers in a flat earth in the past was not just a relatively recent urban myth to make our modern day selves feel superior.
Coin is flat, but spinning coin looks like a sphere.
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Formally, it can be a result of somekind of atmospheric refraction.
Refraction moves the apparent position of an object complete with its horizon, it does not produce an obscuring effect. Try tracing out the ray diagrams.
Coin is flat, but spinning coin looks like a sphere.
Spinning at that speed, the stars would appear to be a blur.
If you have an alternative theory to the spherical earth please post it in New Theories or It Can't Be True. See http://www.thenakedscientists.com/forum/index.php?topic=66954.0
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I ordered a very inexpensive telescope.
360/50mm. Can anyone explain to me what this means? I'm assuming it's sufficient to view past a few 100km since these things look at stuff in space.
Is it dangerous to use these things in daylight? I recall reading that looking at the sun with a telescope destroys your eye.
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Formally, it can be a result of somekind of atmospheric refraction.
Refraction moves the apparent position of an object complete with its horizon, it does not produce an obscuring effect.
Usually - yes. But there are such thing as "negative refraction".
Spinning at that speed, the stars would appear to be a blur.
May be, may be not. May be celestial sphere with stars are moving too.
If you have an alternative theory to the spherical earth please post it in New Theories or It Can't Be True. See http://www.thenakedscientists.com/forum/index.php?topic=66954.0
I have no alternative theory, of course. I just wanna say, that there are no such thing as "proof" in natural science. And topicstarter can't "disproof" model of "flat Earth", becouse there are no any working models of it.
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One of the most obvious reasons that we know that the Earth is not flat is because artificial satellites could not stay above a flat Earth. They'd fall down. However they can easily orbit the spherical Earth.
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The best evidence that the world is flat is the way projectiles move under the influence of gravity, it is widely reported that they move in a parabolic path which only happens because the world is flat and of infinite extent.
if the earth was spherical they would take an elliptical path
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Everyone gets a prize.
The earth is flat enough for those who want it to be, and adequately spherical for those of us who need it so.
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I would like someone skilled in math's to work out what the difference in range would be for a large gun such as was developed in WWII with a range of say 45 miles if the landing point was calculated using either parabolic or elliptical parameters.
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According to GR, doesn't mass and gravity cause space-time to curve. So, it is possible that space-time is curved, but the earth is flat?
In other words, if the earth suddenly loss all its mass, but retained all its substance (without mass) space-time around the earth would lose curvature, therefore wouldn't the earth flatten? Satellites would not be able to follow a curved path around the earth with GR=0, and would treat the earth like it was a plain.
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The best, well I think so, way of demonstrating that the earth rotates, thus it must be round given that the sun comes up and sets at different times as you go East/West is the droped rock experiment;
Get a rock and tie a piece of cotton thread arond it so you can suspend it from a high point. This will have to be done in doors where there is no wind to push it off course. Churches are good for this but any high place will do, stairwell for example.
Have the rock dangle from the high point so it touches the ground. Make sure it's settled down and is not swinging about. Mark the position on the floor.
Then take the rock up to the top of what ever you suspended it from, a nail or hook or what ever. It will swing about horizontaly as you do this. Calm it down and have it a couple of inches below the high point.
The position you have marked on tghe floor is directly below the high point where you now have the rock.
Cut the cotton thread with something that will impart no sideways motion. Burning through it with a lighter will do nicely.
The rock will drop down and hit the floor a little East of the point directly below the high point.
This is because the ceiling is traveling faster than the floor. When the rock leaves the ceiling it has the same speed as the ceiling and whilst it is dropping down to the floor it is traveling slightly faster than the bits of wall it's passing.
It might be good to use a sand tray to both mark the position and to drop the rock onto as this will show the difference between the two and stop the rock bouncing all over the place.
You can calculate the size of the earth and your lattitude from this should you want to do the maths.
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The best evidence that the world is flat is the way projectiles move under the influence of gravity, it is widely reported that they move in a parabolic path which only happens because the world is flat and of infinite extent.
if the earth was spherical they would take an elliptical path
Ha ha. Very funny. :/
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According to GR, doesn't mass and gravity cause space-time to curve. So, it is possible that space-time is curved, but the earth is flat?
Mass can cause spacetime to curve. However its incorrect to say that gravity causes it to curve because spacetime curvature manifests itself as gradients in the gravitational field. In other words, spacetime curvature and tidal gradients are exactly the same thing.
In other words, if the earth suddenly loss all its mass, but retained all its substance ...
Which is impossible.
..(without mass) space-time around the earth would lose curvature, therefore wouldn't the earth flatten?
No. There would be no reason for a spherical body to change its shape if it started out as spherical and no external forces are acting on it.
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Telescope is arriving in a week I hope.
I don't have access to satellites or projectiles, unless it's a bb gun. Maybe I can do an experiment with that.
I like the rock experiment Tim. Might take a bit of work setting it up. If my telescope experiment suggests the earth is flat (disproves spherical model) then I'll do the rock thing next.
Honestly, I think it's a bit exciting if the earth is flat. Makes you wonder and changes your whole world view.
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Why so many posts with an obvious answer.
"No, the earth is not flat Period case closed!
Alan
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The best, well I think so, way of demonstrating that the earth rotates, thus it must be round given that the sun comes up and sets at different times as you go East/West is the droped rock experiment;
Get a rock and tie a piece of cotton thread arond it so you can suspend it from a high point. This will have to be done in doors where there is no wind to push it off course. Churches are good for this but any high place will do, stairwell for example.
Have the rock dangle from the high point so it touches the ground. Make sure it's settled down and is not swinging about. Mark the position on the floor.
Then take the rock up to the top of what ever you suspended it from, a nail or hook or what ever. It will swing about horizontaly as you do this. Calm it down and have it a couple of inches below the high point.
The position you have marked on tghe floor is directly below the high point where you now have the rock.
Cut the cotton thread with something that will impart no sideways motion. Burning through it with a lighter will do nicely.
The rock will drop down and hit the floor a little East of the point directly below the high point.
This is because the ceiling is traveling faster than the floor. When the rock leaves the ceiling it has the same speed as the ceiling and whilst it is dropping down to the floor it is traveling slightly faster than the bits of wall it's passing.
It might be good to use a sand tray to both mark the position and to drop the rock onto as this will show the difference between the two and stop the rock bouncing all over the place.
You can calculate the size of the earth and your lattitude from this should you want to do the maths.
Contrary to Foucault pendulum, your experiment works best at equator and won't work at earth poles.
You would need a considerably tall building to get noticeable result.
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Telescope is arriving in a week I hope.
I don't have access to satellites or projectiles, unless it's a bb gun. Maybe I can do an experiment with that.
I like the rock experiment Tim. Might take a bit of work setting it up. If my telescope experiment suggests the earth is flat (disproves spherical model) then I'll do the rock thing next.
Honestly, I think it's a bit exciting if the earth is flat. Makes you wonder and changes your whole world view.
You would have bought the worst telescope ever made if it proves the earth is flat!
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I have my telescope. Magnification is 90x, so I really hope this is sufficient. It does seem like a POS though.
Going to use a ship tracking website and a very nice spot that can see ship traffic for quite a distance. I'm hoping that I'll have good timing and either watch a ship sink into or appear from the horizon or neither.
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The best evidence that the world is flat is the way projectiles move under the influence of gravity, it is widely reported that they move in a parabolic path which only happens because the world is flat and of infinite extent.
if the earth was spherical they would take an elliptical path
Ha ha. Very funny. :/
It's threads like this that cause me to question my participation here at TNS. If it weren't so amusing, as Pete has suggested, it would simply be a waste of valuable time to even respond to such nonsense.
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Telescope is arriving in a week I hope.
I don't have access to satellites or projectiles, unless it's a bb gun. Maybe I can do an experiment with that.
I like the rock experiment Tim. Might take a bit of work setting it up. If my telescope experiment suggests the earth is flat (disproves spherical model) then I'll do the rock thing next.
Honestly, I think it's a bit exciting if the earth is flat. Makes you wonder and changes your whole world view.
You should be able to do it in a cave. You should then be able to work out how far north south you are from the distance it lands away from the point directly below it's drop point and the time the earth takes to rotate and the size of the earth. Or any 1 of the 3 when you know the others.
At least I think so, it's been 30 years since I did any such maths... I might need help....
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Contrary to Foucault pendulum, your experiment works best at equator and won't work at earth poles.
You would need a considerably tall building to get noticeable result.
If the earth is flat, it won't have an equator or poles.
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So I came across a youtube video of a man jumping 25000ft with no parachute and I could clearly see the curvature of the earth. However, I think the flat earthers would say that it's all green screen or video magic lol
EDIT: Some people are actually saying it's fake
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Who cares what anyone else says? Other people believe in all sorts of drivel and even vote for Trump. All that matters in science is what you do, what you observe, and how you explain it. There's sometimes a consensus among sane and honest people, but even that can be wrong.
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Who cares what anyone else says? Other people believe in all sorts of drivel and even vote for Trump. All that matters in science is what you do, what you observe, and how you explain it. There's sometimes a consensus among sane and honest people, but even that can be wrong.
I really like this thread.
There are thsoe out there who believe (I'm always a little stretched by the word in this context) that the world is flat. This guy (the OP) wants to check.
That is science.
Well done.
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If the earth is flat, it won't have an equator or poles.
If the earth is flat, it may have one pole and one boundary.
The circle centered at the pole having radius half the earth's radius is then called the equator.
They often refer to UN emblem.
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According to GR, doesn't mass and gravity cause space-time to curve. So, it is possible that space-time is curved, but the earth is flat?
Mass can cause spacetime to curve. However its incorrect to say that gravity causes it to curve because spacetime curvature manifests itself as gradients in the gravitational field. In other words, spacetime curvature and tidal gradients are exactly the same thing.
In other words, if the earth suddenly loss all its mass, but retained all its substance ...
Which is impossible.
..(without mass) space-time around the earth would lose curvature, therefore wouldn't the earth flatten?
No. There would be no reason for a spherical body to change its shape if it started out as spherical and no external forces are acting on it.
The spherical body may not change, but the tides and orbits will change unable to follow curved space-time; flat orbits. The point I was making is the theory of the flat earth, was around before they knew of GR. Therefore, GR would not have been one of the variables they could have used. If you factor GR out from all consideration, you also need to factor out the curvature of space-time. I am not saying the earth is flat, only the logic of the old theory would have become limited by lack of this premise. 20/20 hindsight always gives one an advantage.
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If the earth is flat, it won't have an equator or poles.
If the earth is flat, it may have one pole and one boundary.
The circle centered at the pole having radius half the earth's radius is then called the equator.
They often refer to UN emblem.
Then the pendulum thing would work everywhere. Given it does not work at the equator this idea is out.
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Best example ever. I don't know how to place a hyper link. Replace "x's" with "t's" in "hxxps".
hxxps://www.youtube.com/watch?v=B8QWuSn_Wxw
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Hoping to do my first expedition soon but the weather is incredibly hot and I'll cook under the sun in the couple hours I need to do this.
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Of course the earth is flat... there is so much here to prove it......
http://www.theflatearthsociety.org/home/index.php/flat-earth-library/library-books
LOL.
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Of course the earth is flat... there is so much here to prove it......
http://www.theflatearthsociety.org/home/index.php/flat-earth-library/library-books
LOL.
A dozen or so books is at least something. But compared to the thousands (or more) on globe earth or based on it?
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I finished the experiment. Here's the video:
Thanks for your support!
I wonder what people think.
EDIT: link not working, maybe this: youtu.be/QwQExaWbzSw
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Okay so my math needs some corrections (I blame you guys lol), I think. According to some other forums, because the buildings are partially visible, the earth is round. I'm going to spend some time soon correcting the math to support the hypothesis that objects disappear under curvature.