[reer]

Often you see long-exposure photos of stars, and how they circle around the celestial poles, such as this one:



This image is one of many on https://earthsky.org/astronomy-essentials/what-are-star-trails

You can see that many of the stars clearly dip below the horizon. As far as I understand it, this would not be possible on a FE; the stars should dip down, but never go below the horizon. Of course this assumes the horizon is flat, such as the ocean on the right-hand side of this image.

Can one of the FEers explain this to me?

[jack44556677]

I highly recommend reading the wiki here first.  Most all of your 101 questions have at least some mention there.

The reason for the star trails is that the stars are in motion, and move in large circles above our heads.

Much like you cannot see the town a few miles down the road, the amount of these circles that you can see from any one place on earth as a human is both limited and finite.

This is the reason you can't see the distant town (assuming it is parallel to you), AND the reason you can't see the entire circle that every star makes.

The horizon is always flat, and is an optical illusion (not the physical edge of something, as we were incorrectly taught).  This fact is regardless of the shape of the earth or conceptions thereof.

[SteelyBob]

The reason for the star trails is that the stars are in motion, and move in large circles above our heads.

But if they were moving in large circles above our heads, they would appear as ellipses, would they not, due to perspective, unless the observer happened to be directly underneath the centre of rotation? And if, as you suggest, human ability to perceive the stars was a factor, then one would expect the circles to both shrink and get dimmer as the stars got close to the edge of our perception. But that's not what we see, is it? The star trails are quite clearly perfectly circular, each star remains at a constant level of brightness regardless of where it is in its circular journey, and they would be complete circles everywhere if it wasn't for the horizon being in the way - what is happening is quite clearly obscuration by the earth. Human eyesight limitations do not change the path that light takes - whether you're looking at something with human eyes, eagle's eyes, or the world's most powerful telescope, the light will still take the same path - all that changes is the ability of the sensor to sense the smallest amounts of light and resolve small details. The FET arguments around perspective seem very muddled on this subject.

Then if we consider moving location, the only thing that changes is the elevation angle of the two stars at the very centre of the two visible concentric rings, the two respective pole stars, which is why you can only see one of the two from any one latitude on the planet.

This is all entirely consistent with a globe shaped earth whose axis of rotation is aligned with the two respective pole stars.

[Action80]

The set of all distant points from the x-axis in 3 dimensional space can be likened to the set of all distant points from the x-axis in 2 dimensional space. If rotated about the x-axis it forms a tube.

[jack44556677]

@SteelyBob

But if they were moving in large circles above our heads, they would appear as ellipses, would they not, due to perspective, unless the observer happened to be directly underneath the centre of rotation?And if, as you suggest, human ability to perceive the stars was a factor, then one would expect the circles to both shrink and get dimmer as the stars got close to the edge of our perception.

I should have said "circular paths" to cover that possibility.  The honest answer is we don't know much about what we are looking at, or what we are looking at it through (or possibly even ON / a part of a larger structure or aggregation of matter).  When dealing with things so far away (we presume from their apparent lack of parallax), we wouldn't necessarily expect much perspective or brightness warping to occur in any case (largely dependent on how far away or bright they are initially, and how far they actually travel away from the observer during their apparent loops)

The FET arguments around perspective seem very muddled on this subject.

They are as varied and numerous as the stars we are discussing!  Each person has their own understanding, and many (if not all, to some degree) are muddled.

which is why you can only see one of the two from any one latitude on the planet.

You ought to know that that isn't strictly true, but in any case the reason you can only see certain stars is due to the finite limits/bounds of your sight.  It depends on where you are if you can see the eifel tower or not, for the exact same reason.  You can be standing with a clear line of sight to the eifel tower (or any distant object, yes - including stars) and not be able to see it on a perfectly clear day, just as a result of your distance away from it.

This is all entirely consistent with a globe shaped earth whose axis of rotation is aligned with the two respective pole stars.

Perhaps that is one of the reasons people have had it wrong for so very long.  They believed the earth was round, and then when they went to look for supporting evidence of that belief, they found things - like the apparent rotation of the lights in the sky - that seemed to support it.  When you see something is moving, it doesn't necessarily mean you are!  As it turns out, there are ways to test wether you are moving or not.

@action80

And those same distant points around an observer in 3 dimensions would form a sphere.  What's your point?

[JSS]

which is why you can only see one of the two from any one latitude on the planet.

You ought to know that that isn't strictly true, but in any case the reason you can only see certain stars is due to the finite limits/bounds of your sight.  It depends on where you are if you can see the eifel tower or not, for the exact same reason.  You can be standing with a clear line of sight to the eifel tower (or any distant object, yes - including stars) and not be able to see it on a perfectly clear day, just as a result of your distance away from it.

That isn't true. You can't attribute the stars variable visibility by location simply to the "finite limits/bounds of your sight".

You can see the North Star from both Vietnam and Venezuela and they are over 15,000km apart.

But travel south and soon you can't see the North Star from Manaus in Brazil, which is less than 2,000km away.

Also, the stars don't just slowly fade from view. There is no point on the Earth where you can watch a star fade into the sky as you move. It sinks below the horizon. If it were just getting too far away then you would see the stars fade in and out. But they don't do that, and in fact you should see the stars directly above bright, and get dimmer the further down you look since they are supposed to be further away. This also does not happen. I've taken enough panoramic shots of the sky to see this for myself.

[reer]

I must be missing something. If the stars (and sun, moon, etc) were always above the horizon, then their tracks might pass very close or even on the horizon, depending on our position. However, it would be clearly impossible for some of those stars to dip vertically below the horizon. No matter what the wiki says, this is clearly not possible if the stars are above the horizon. None of the talk about circles, ellipses, 3D projections, etc can make those stars go down vertically. However, this is trivial to explain if you assume the earth is a rotating globe.

If this is explained in the wiki, please direct me to it, as I could not find it.

[SteelyBob]

If this is explained in the wiki, please direct me to it, as I could not find it.

You're not missing anything. The wiki tries to invoke several different ideas, but they all fall apart on closer analysis.

There's a very odd argument about perspective, whereby the shortcomings of human vision are used to bring forward the 'vanishing point', which is discussed in quasi-scientific referential terms as if it's a 'thing' in anything other than art class, from infinity to some finite point in front of the viewer.  This is used to explain why the stars get lower in the sky, but it completely fails to explain why they retain their relative angular separation regardless of their position in the sky.

There's also the even odder idea of 'EA', which is allegedly an as-yet undetected process or force by which light is bent upwards over long distances. This is also used to explain why the sun, moon and stars get low in the sky, and disappear below the horizon, despite allegedly being above us, although again, it completely fails to actually explain what we observe - completely undistorted (barring refraction effects close to the horizon) circular star trails, half the sun/moon visible above the horizon at rise/set times...the perfect relationship between latitude and the elevation angle of the pole stars, the fact that all the other stars appear to rotate around the pole stars...the fact that the southern pole star is visible, due south, wherever you are in the southern hemisphere. None of it is explained in any credible way.

[jack44556677]

@reer

The wiki isn't flawless, but it does a great job of providing an overview/sense of the disparate and often conflicting views there are out there.

That said, yes - you did miss it : https://wiki.tfes.org/Sunrise_and_Sunset

However, it would be clearly impossible for some of those stars to dip vertically below the horizon.

Only when you misunderstand optics.  Things that become more and more distant from you appear to converge into the horizon (and ultimately become a part of it).  There is more going on than just that however.  The other major factor is refraction cased by the density gradient in our air.  These are what is most responsible for diverting the light away from your eyes, and are the cause of the optical illusion of "setting" (stars, the sun/moon, boats, you name it).

[SteelyBob]

Things that become more and more distant from you appear to converge into the horizon

Things that become more distant also appear to get closer together though, as well, don't they? The angle subtended at your eyes by two points gets less and less and they get further away.

But the stars don't do that, do they? They don't converge. They just stay the same distance apart, and merrily rotate around the pole stars in perfect circles.

[JSS]

However, it would be clearly impossible for some of those stars to dip vertically below the horizon.

Only when you misunderstand optics.  Things that become more and more distant from you appear to converge into the horizon (and ultimately become a part of it).  There is more going on than just that however.  The other major factor is refraction cased by the density gradient in our air.  These are what is most responsible for diverting the light away from your eyes, and are the cause of the optical illusion of "setting" (stars, the sun/moon, boats, you name it).

This view is not supported the evidence. There is no amount of refraction that will cause a star that is directly overhead to descend smoothly and without distortion all the way down the sky to the horizon.  This amount of refraction has simply never been observed, and would require a truly massive variation in heat and pressure to occur, which has also never been measured. 

There is also no simulation of this effect that can produce the results we see. No computer program that shows what the Flat Earth sky actually is, and then calculates what we see from it.  If you can not describe your effect with enough detail to make predictions, it's not a theory, it's not even a hypothesis since you can't test it.  It's just a guess.

Another very good piece of evidence against the entire sky being an optical illusion is we have deep space radar which can bounce radio signals off objects like the Moon and Venus, and they are exactly where they appear to be.  We have even launched physical objects to the moon and landed them on it, which would be hard to do if it wasn't right where we see it.

[SteelyBob]

This view is not supported the evidence. There is no amount of refraction that will cause a star that is directly overhead to descend smoothly and without distortion all the way down the sky to the horizon.  This amount of refraction has simply never been observed, and would require a truly massive variation in heat and pressure to occur, which has also never been measured. 

There is also no simulation of this effect that can produce the results we see. No computer program that shows what the Flat Earth sky actually is, and then calculates what we see from it.  If you can not describe your effect with enough detail to make predictions, it's not a theory, it's not even a hypothesis since you can't test it.  It's just a guess.

Another very good piece of evidence against the entire sky being an optical illusion is we have deep space radar which can bounce radio signals off objects like the Moon and Venus, and they are exactly where they appear to be.  We have even launched physical objects to the moon and landed them on it, which would be hard to do if it wasn't right where we see it.

Spot on. I think it's best we avoid discussion of space travel though. For you and me, that might be compelling evidence, but if you've formed the view that it was all faked, then no amount of video evidence, or witness accounts, or anything, is going to convince you otherwise. But the interesting thing, I think, is that of course even if NASA did fake going to the moon, even if every space agency in the world is faking it, even if every micro satellite firm is engaged in some elaborate hoax, the funding for which is mysteriously ever-present, it doesn't change the shape of the world, which could be either flat or round. If space videos are real, the earth is a globe. If they're fake, the earth is either a globe or flat.

That's why the stars questions, like this one, are so good. They are absolutely the kind of observational, anyone-can-do-it science that FET claims to be based on. And of course, as you rightly say, what we observe makes no sense whatsoever on a flat earth. There is no single FET model that can even approximately predict the positions of the sun, moon and stars as they change with time, or with observer location. Somebody truly engaged in some kind of observational, or or indeed zetetic science, would question why the observation doesn't fit their assumptions or hypothesis, and change their thinking.

[JSS]

Spot on. I think it's best we avoid discussion of space travel though. For you and me, that might be compelling evidence, but if you've formed the view that it was all faked, then no amount of video evidence, or witness accounts, or anything, is going to convince you otherwise.

I can't agree on this point. If we were to avoid every subject that a Flat Earther disagrees with or thinks is part of 'the conspiracy' then we have to throw out everything. Eventually we have nothing at all to discuss because all evidence is contested.

This thread is a good example, the entire field of astronomy is dismissed with the claim that we don't really know what we are looking at, or through, or on when in fact we do know quite a bit about all of these. Those being stars, the atmosphere and the Earth.

[SteelyBob]

My point is that the only way you will ever persuade a flat earther that the moon landings weren't faked, or that all the ISS footage etc is real, is by physically strapping them into a rocket and sending them into space. Nothing else will do - it's all part of the conspiracy. But the equally important point is that it's irrelevant - even if they were correct, it still proves nothing about the shape of the earth.

The stars, however, and all the good points you've made here are a different game, because if any of the FET assumptions or ideas are shown to be false, then it can't be flat. For obvious reasons, points that are irrelevant or nebulous, like whether coriolis affect water in sinks, or whether a particular ISS video is fake, tend to get a lot of replies - it's the comfort zone of confusion. Precise, direct questions usually get ignored in the noise, so I prefer to keep it on the point, so to speak, and avoid adding to the noise.

Just my thoughts - apologies if that comes across wrong. You're making some great points - thanks.

[Jay Seneca]

Often you see long-exposure photos of stars, and how they circle around the celestial poles, such as this one:



This image is one of many on https://earthsky.org/astronomy-essentials/what-are-star-trails

You can see that many of the stars clearly dip below the horizon. As far as I understand it, this would not be possible on a FE; the stars should dip down, but never go below the horizon. Of course this assumes the horizon is flat, such as the ocean on the right-hand side of this image.

Can one of the FEers explain this to me?

Not sure where this video was taken but you can see Ursa Major any time of the year and time of the night in all of the US. I live in southeast US around 30 latitude and I know this to be true. This shouldn’t be possible on RE.

[Iceman]

This shouldn’t be possible on RE.

What is the basis for that opinion?

[Iknowthetruth69]

Well it’s because we have big brain and my mommy told me that it’s true and wold mommy evr lie

[SteelyBob]

Not sure where this video was taken but you can see Ursa Major any time of the year and time of the night in all of the US. I live in southeast US around 30 latitude and I know this to be true. This shouldn’t be possible on RE.

You're right, it shouldn't be possible to see all of Ursa Major any time of the year and all night in all of the US. The 'big dipper', or the bit of Ursa Major that most people recognise, is visible from most of the states all year round, but only Dubhe, with a declination of 61, would be visible from 30 north all the time (because 30 + 61 > 90). The lowest star in the big dipper, alkaid, is at 49 degrees declination, meaning you'd need to be north of 41 degrees latitude for it to be circumpolar. At 30 north I'd expect most of Ursa Major to be below the horizon, especially in the winter.

If you're experiencing something different to that you are either a) looking for the wrong stars or b) in possession of one of the most earth-shattering observations made by a modern amateur astronomer, and you should definitely tell more people about it, because you could make some serious money out of it. You would be disproving every star almanac, every internet star calculator app...everything. You should start with a video, showing today's paper, some recognisable part of where you live so we can verify the location and then a picture of the whole of Ursa Major.

https://earthsky.org/tonight/where-is-the-big-dipper-on-these-octber-evenings

I look forward to seeing it.

[Longtitube]

Not sure where this video was taken but you can see Ursa Major any time of the year and time of the night in all of the US. I live in southeast US around 30 latitude and I know this to be true. This shouldn’t be possible on RE.

First of all, by Ursa Major, do you mean all of the constellation or just the Big Dipper? The Dipper, also known as the Plough, although part of Ursa Major, is not the whole constellation.

Second, from a SE USA location like Albany, Ga (picked at random for its 31deg N latitude) most of Ursa Major dips below the horizon for a few hours in each 24, Dubhe skimming the northern horizon. At this time of year it’s mostly above the horizon by 8pm local time and doesn’t dip below the horizon at all before sunrise.

Lastly, from Miami (about 25deg N), Ursa Major disappears entirely below the northern horizon during part of each day.

On what grounds should any of this be impossible??

[JSS]

My point is that the only way you will ever persuade a flat earther that the moon landings weren't faked, or that all the ISS footage etc is real, is by physically strapping them into a rocket and sending them into space. Nothing else will do - it's all part of the conspiracy. But the equally important point is that it's irrelevant - even if they were correct, it still proves nothing about the shape of the earth.

The stars, however, and all the good points you've made here are a different game, because if any of the FET assumptions or ideas are shown to be false, then it can't be flat. For obvious reasons, points that are irrelevant or nebulous, like whether coriolis affect water in sinks, or whether a particular ISS video is fake, tend to get a lot of replies - it's the comfort zone of confusion. Precise, direct questions usually get ignored in the noise, so I prefer to keep it on the point, so to speak, and avoid adding to the noise.

Just my thoughts - apologies if that comes across wrong. You're making some great points - thanks.

Oh, it didn't come across wrong at all, just expressing my thoughts. It's always possible to disagree politely.

The problem with your approach is that to an FE, nothing can be proven.  Take them up in a rocket, and they can say the windows are just CGI.  I've had this used on me before.  The stars?  Just projections on the dome, another reason I've been told. Holograms.  Or as we saw here recently, maybe the whole universe is a simulation, therefore the Earth is Flat. Try and argue around THAT one.

There is literally nothing you can say that can't be dismissed, so trying to seperate arguments into stuff they can believe and stuff they can't is kind of a fools errand. There is never going to be any evidence that will be acceptable. They have already rejected more evidence than you will ever be able to present, even if you type all day.

Still, it's an interesting challenge, and makes one think, and it';s always good to challenge your own assumptions.  And admit it... you kinda WANT them to present something you can't refute, because that would be FASCINATING.  One can always hope.

Star trails are good because they are so well studied and so well explained that you have a large body of evidence and reasoning to draw upon. I have used all kinds of telescopes and cameras and equipment, and it's the most fun when I can use them to take my own evidence.  I'd made star trail pictures, I've even posted some.  I can explain them by the spinning of a round Earth and far away stars. I have yet to look for a star where it's supposed to be and not see it.