Teach a physicist (me) about FET

Not going into the arctan stuff because I don't want to just repeat myself all over again.

Then you shouldn't have started spouting such bullshit about it in the first place to "correct" me.

And if you'd made that argument, I would have been able to respond.

I don't need to make that argument.
You made a baseless claim.
The burden isn't on me to prove it wrong, it is on you to prove it correct.

Yes, light can easily deviate from the straight path and go back in an effort to cancel it, but then there'd be a light wave that in turn cancels out that. The shortest path, being unique, is the only one that basically can't be paired off.

You are aware they don't need to exist in pairs to be eliminated?
Forget about going between 2 points and just consider light propagating.
There are infinitely many unique paths.
Having a destination point doesn't magically change that.
A path in the exact opposite direction would also be unique and thus be another one that can't be paired off.
This can then be used to pair off the o

And yes, like I said, this is handwaved because it's quantum physics and I'm a mathematician, but I'm pretty confident in the basic principle.

I'm not. I call bullshit on it. If you are going to continue asserting, I demand you prove it.
Until you do, I will continue to dismiss it as pure bullshit.

If you like, I can even give you a better counter-example, the double slit experiment, where the light propagates as a wave, and takes both paths rather than travelling the unique shortest path.
It travels as a straight line (technically infinitely many of them), until it gets blocked by a wall and can only pass through 2 slits, which disrupts the wave function and causes it to propagate out again in straight lines from the slit, which can then interact and constructively and deconstructively interfere.

You also need to show that what makes it special is that it is the shortest path, rather than it being straight/not curving relative to the space.

What do you think being straight is? Literally the definition of a straight line, or of a geodesic, is the shortest distance between two points. They are equivalent statements.
[/quote]
I told you what being straight is.
There are numerous aspects to a straight line.
One simple one is a line of the form y=mx+b (I notice my previous one was incorrect, in 3D you need 2 equations to have the line or need to have it in parametric form (with 3 equations then).
The definition of a geodesic is the shortest distance between 2 points.

Notice how these are not equivalent statements?
So no, they are not equivalent.

Another big difference, a geodesic needs 2 defined points, the start and the end, with the geodesic running between them.
The geodesic ends at these points.
A straight line does not necessarily.
A straight line can continue without limit.

Also, remember a key thing which started this debate?
Flat Earth in non-flat space.
A flat object is a plane, which is composed of infinitely many straight lines.

In this non-flat space that this "flat" Earth is meant to be in, these "straight" lines follow the surface of Earth for it to be flat.

Yet, when considering 3D, these "straight" lines are not the shortest path between 2 points.

"In space, light travels along geodesics. This explains why light is bent in gravitational fields. Because gravitational fields bend space and time, the geodesics through those regions of space are also bent."

I asked you to prove it, not just provide more links to baseless claims.
This doesn't explain anything, it just repeats your assertion.

The same applies to your other links.

"Light travels along a geodesic path—the “straightest”* line between points"

This one is great.
What does the "*" mean?
Well, if you go to the bottom, as well as shortest, the other option it gives is the longest.
So is the geodesic path the longest line between two points?

Are we done yet? Hardly homework to type 'light travels along geodesics' into google.

No. Can you explain any of it, in any kind of rational way to justify it?
Also, it isn't that hard to type anything into google and get a bunch of crap which justifies it.

Also note that it isn't just that it follows geodesics I want you to back up, it is your alleged quantum mechanical origins of it.

Sure, my explanation of the underlying principle wasn't great, because I though this much was common knowledge. Geodesics are just a generalisation of a straight line; if you believe light travels in a straight line, then it travels along geodesics. The only notion of straightness that you get in a 'curved' space is the geodesic.

And that would require that the flat Earth be situated along geodesics.

That is exactly what a straight line is defined as. The reason a straight line is of that form is because they crunched the numbers for calculating a geodesic in Euclidean space and the answer was 'anything that follows that equation.'
The only 'equivalent' of that in non-flat space would be a geodesic.

No, a geodesic is not the only equivalent of that in non-flat space.
In simple polar space we can construct numerous curves which are not what you are claiming geodesics are.

Jackblack, this is just silly now. You are ignoring established scientific fact, apparently just because you want to continue arguing. You got physics lecture notes, published books on the mathematics of relativity, with text copy-pasted straight out of them, and apparently that's not enough. Is there any source I could provide that would count, or are you just going to reject everything now?
I'm not claiming my explanation of the mechanism is meant to be convincing or perfect. Like I said, this is established scientific fact and your refusal to confirm or accept that just baffles me. I was just giving a vague overview of how I remember having it explained. If you know anything about quantum physics you ought to know the role probabilities play.
The only interesting question is the idea of how a flat Earth would look, but that could be determined the same way we know the Earth goes around the Sun, under RET. Reference frames are mathematically fine to switch around in, but practically you need an explanation for all the motion and forces exerted. A round Earth in Euclidean (well, Minkowski as you seem to like being picky for no good reason) space and a flat Earth in some well-designed non-Euclidean space could be made to be indistinguishable on a mathematical level, but the issue you then run into is how you explain, say, the Coriolis force. That's a fun topic of discussion, and the kind of thing I come to this forum for, not this "Scientific fact is wrong because you said it first."

You are thinking of a line segment. A line is infinite.

It's just easier to say 'line' in forum discussions.

Jackblack, this is just silly now. You are ignoring established scientific fact, apparently just because you want to continue arguing. You got physics lecture notes, published books on the mathematics of relativity, with text copy-pasted straight out of them, and apparently that's not enough. Is there any source I could provide that would count, or are you just going to reject everything now?

Like I said, I want an explanation, especially one which matches your claim.

I have also seen plenty of lecture notes with massive flaws in them, such as ones that claim in order for Beer Lambert's law to hold you need to have a low concentration to prevent "shadowing" of the absorbing molecules, and thus at high concentrations, the law will no longer hold due to some particles blocking the light going to other ones.
While in reality, that is required for the law to hold.

The examples you provide either baselessly assert it or appeal to relativity instead of quantum physics.
The appeals to relativity appeal to the curvature of spacetime and deal with geodesics in space-time.

These are fundamentally different to ones in space.
A simple example is gravitational lensing.

With this, light appears to travel in a curved path through space, but goes along a "straight" path through space time.

Some even indicated that light is following the space-space curvature and the space-time curvature.

Then there is the other big issue, after looking into it more, a geodesic doesn't appear to be the shortest path.
For example, a single geodesic (well, the image of one so it continues past the 2 points it is connecting) on an elipse:
https://upload.wikimedia.org/wikipedia/commons/a/a9/Circumpolar_geodesic_on_a_triaxial_ellipsoid_case_A.svg

Would light happily travel along that?

The only interesting question is the idea of how a flat Earth would look

And fundamental to how things look is how light behaves as that is what you use to view things.

A round Earth in Euclidean (well, Minkowski as you seem to like being picky for no good reason) space and a flat Earth in some well-designed non-Euclidean space could be made to be indistinguishable on a mathematical level, but the issue you then run into is how you explain, say, the Coriolis force.

And the other big issue is explaining that minkowski, especially when it seems to be arbitrarily defined to say "hey look Earth is flat"

Quote from: sokarul on June 06, 2017, 05:38:52 PM

You are thinking of a line segment. A line is infinite.

It's just easier to say 'line' in forum discussions.

Is a geodesic a line or a line segment?

Like I said, I want an explanation, especially one which matches your claim.

I have also seen plenty of lecture notes with massive flaws in them, such as ones that claim in order for Beer Lambert's law to hold you need to have a low concentration to prevent "shadowing" of the absorbing molecules, and thus at high concentrations, the law will no longer hold due to some particles blocking the light going to other ones.
While in reality, that is required for the law to hold.

The examples you provide either baselessly assert it or appeal to relativity instead of quantum physics.
The appeals to relativity appeal to the curvature of spacetime and deal with geodesics in space-time.

These are fundamentally different to ones in space.
A simple example is gravitational lensing.

With this, light appears to travel in a curved path through space, but goes along a "straight" path through space time.

Some even indicated that light is following the space-space curvature and the space-time curvature.

Why does it matter what the explanation is? I'm not claiming to be an expert in quantum physics, I'm providing sources for a statement of fact. I'm quoting a module I took about five years ago offhand, my explanation's not going to be great, but it doesn't matter, I'm talking about the fact, not the proof.
You have been shown consistently that it is accepted scientific fact that light travels along geodesics, and I am genuinely amazed that you apparently don't know that already. Why does it matter whether the explanation I have repeatedly said is handwaved works when the sources I have given hold regardless? Of course they 'assert' it, they are quoting common knowledge.

If you really want to try and get into a detailed explanation you're welcome to dive headfirst into quantum states and the principle of least action and Feynman path integrals but, sure, that could be fun but is this really necessary to get you to accept a fact you've been given multiple sources for, and can easily find countless more? Given that you're apparently asking me to source quantum physics, well if you've ever tried to research topics like that you'll know you either get absurdly childish depictions or inaccessibly technical articles, and nothing in between.

http://www.thephysicsmill.com/2013/07/16/reality-is-the-feynman-path-integral/
Patronizing, but you get the "Instead, the particle is a wave… and it doesn’t take one path from the initial position to the final position, it takes all possible paths."
http://lesswrong.com/lw/pk/feynman_paths/
Bit more technical sides, albeit incomplete.
https://en.wikibooks.org/wiki/A-level_Physics_(Advancing_Physics)/Quantum_Behaviour#Many_Paths
Back to basics. "In fact, what photons do when they are travelling is to take every path possible." "However, just because a photon could end up anywhere in space does not mean that it has an equal probability of ending up in any given place."
https://transactionalinterpretation.org/2016/06/22/how-light-smells-all-its-possible-paths-from-source-to-destination/

Though, again, this is quantum physics. If you're looking for an easy, intuitive answer you're in the wrong subject, and basically every article is going to be a simplification because readers generally aren't quantum physicists. Just accept scientific fact already.

Then there is the other big issue, after looking into it more, a geodesic doesn't appear to be the shortest path.
For example, a single geodesic (well, the image of one so it continues past the 2 points it is connecting) on an elipse:
https://upload.wikimedia.org/wikipedia/commons/a/a9/Circumpolar_geodesic_on_a_triaxial_ellipsoid_case_A.svg

Would light happily travel along that?

Well, yes, if it was limited to the surface of the ellipse. We all know, presumably, under RET travelling along great circles give the shortest flight paths. When you're bound to the surface of an object, what do you expect?
What path do you imagine light would take instead?

And the other big issue is explaining that minkowski, especially when it seems to be arbitrarily defined to say "hey look Earth is flat"

Um, no, Minkowski space is just the sum of Einstein's work, appending the fourth dimension (time) and altering the metric to account for what had been observed. It has nothing to do with FET, it's just an example of how we in fact don't like in Euclidean space, and that's why we observe light curving around sufficiently massive objects, etc.

This is ridiculous.

Is a geodesic a line or a line segment?

A whole geodesic is a line. Light isn't going to travel along the whole geodesic though, it'll just follow the one it's on from the source to whatever it hits.

Why does it matter what the explanation is?

Because often people will misstate things because they don't understand the explanation.

So are you actually stating a fact, or just what you think the fact is?

Even professors will get these "facts" wrong some times, and quite often the students will not question it and then go on to repeat these facts, and that can continue to apply until they actually go into a field which needs that and realise it is wrong.


This appears to be an example of that where the light isn't doing what you are saying. Instead, just like the double slit experiment, it takes all paths, not just one.
It doesn't say they magically cancel each other out and only leave one path.

The closest you get to it taking the shortest path is acting like it knows where it's destination is and then solving for that and getting a mathematical model which works in the case of our reality.

But there are also cases which go directly against that, such as interferometers such as those which detected gravity waves.
In this, a much shorter path would be to ignore the interferometer part and just go straight to the detector, but it doesn't. Instead the light pulses travel along the arms of the detectors and back and are recorded.
Similar things happen with laser ranging experiments, where the shortest path would be to just go straight to the detector, but instead they go all the way out to the target and then come back.

I'm not claiming to be an expert in quantum physics, I'm providing sources for a statement of fact.

If you aren't an expert then don't go claiming facts about complex topics which people will often get wrong.
You aren't providing a statement of fact, you are providing a claim.

is this really necessary to get you to accept a fact you've been given multiple sources for, and can easily find countless more?

As I said before, you can typically find multiple sources for any BS claim. That does't make the claim a fact.
So far you have not presented a fact to me, you have presented a claim, a claim you are unable to rationally substantiate.

Just accept scientific fact already.

I will accept it as a fact when it is shown to be.

Quote

Then there is the other big issue, after looking into it more, a geodesic doesn't appear to be the shortest path.
For example, a single geodesic (well, the image of one so it continues past the 2 points it is connecting) on an elipse:
https://upload.wikimedia.org/wikipedia/commons/a/a9/Circumpolar_geodesic_on_a_triaxial_ellipsoid_case_A.svg

Would light happily travel along that?

Well, yes, if it was limited to the surface of the ellipse. We all know, presumably, under RET travelling along great circles give the shortest flight paths. When you're bound to the surface of an object, what do you expect?
What path do you imagine light would take instead?

According to you, it would take the shortest path.
But with that geodesic, there are 2 points basically right next to each other, but instead of travelling along that nice short path, it goes pretty much all the way around the ellipsoid.
Assuming that path follows the curve of the ellipsoid, I am perfectly fine with that path, but it goes directly against your claim of light only taking the shortest path.

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And the other big issue is explaining that minkowski, especially when it seems to be arbitrarily defined to say "hey look Earth is flat"

Um, no, Minkowski space is just the sum of Einstein's work, appending the fourth dimension (time) and altering the metric to account for what had been observed. It has nothing to do with FET, it's just an example of how we in fact don't like in Euclidean space, and that's why we observe light curving around sufficiently massive objects, etc.

This is ridiculous.

Yes, your claims are ridiculous.
Remember what got us started here?
The claim that you could have a flat Earth in non-flat space.
That is the minkowski I am talking about. The one set up to make Earth flat, yet perfectly matching a round Earth in effectively flat space.

Yes, Einstein has spacetime curve, a very tiny amount due to mass, nothing like that required to make Earth flat.

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Is a geodesic a line or a line segment?

A whole geodesic is a line. Light isn't going to travel along the whole geodesic though, it'll just follow the one it's on from the source to whatever it hits.

Then how can it be the shortest distance between 2 points when it continues past it?

This also shows another difference between the geodesic and a straight line.

In Euclidean space, there is a single straight line between any set of 2 points (so 1 line for each pair, where some may be the same line) and if you take any 2 points on that line, you will be able to generate that straight line from it, and it will always be the shortest path.
But for non-Euclidean space, there can be many geodesics between a single set of 2 points, and if you take 2 points on that geodesic you would be able to get different geodesics than from the first pair. More importantly, not all of these are the shortest path.

Because often people will misstate things because they don't understand the explanation.

The whole point of my statement has nothing to do with quantum physics and entirely to do with the fact "Light travels along geodesics." Quantum physics just came up when I tried to give an idea of where the statement came from. Your refusal to accept this is your problem. You've been given sources for everything I said, references to pretty advanced quantum physics if you want the detailed explanation, and you just seem to be rejecting it because you'd rather just argue than be right.
What will it take for you to accept scientific fact?
At this stage it seems like you'll refuse to accept anything until a non-expert in the topic explains bloody quantum physics to you, someone who seems just as willing to argue over whether or not the sky is blue. If that's the case, I'm out.

Yes, your claims are ridiculous.
Remember what got us started here?
The claim that you could have a flat Earth in non-flat space.
That is the minkowski I am talking about. The one set up to make Earth flat, yet perfectly matching a round Earth in effectively flat space.

Uh, what? Minkowski space is not the only type of non-Euclidean space. It is one of an uncountably infinite variety. I just gave it as one example, I never said FET would work in it. It doesn't matter what 'the Minkowski' you're talking about is, there's only one Minkowski space.

Then how can it be the shortest distance between 2 points when it continues past it?

This also shows another difference between the geodesic and a straight line.

In Euclidean space, there is a single straight line between any set of 2 points (so 1 line for each pair, where some may be the same line) and if you take any 2 points on that line, you will be able to generate that straight line from it, and it will always be the shortest path.
But for non-Euclidean space, there can be many geodesics between a single set of 2 points, and if you take 2 points on that geodesic you would be able to get different geodesics than from the first pair. More importantly, not all of these are the shortest path.

A straight line goes on endlessly too, we're only concerned with a limited section. 'Light travels along geodesics,' does not mean 'light traverses all of every single geodesic regardless of whether or not it connects the two points in question.'
As for "there can be many geodesics between a single set of 2 points," that is just completely wrong. You can draw multiple geodesics that pass through one point, but that pass through two? That might be possible with, say, antipodal points on a sphere, but the great circles connecting them would be the same length so it doesn't matter. One geodesic connecting two arbitrary points, though?
Won't happen. The whole definition of a geodesic is "The shortest possible distance between two points." Not all spaces are going to be like spheres, where if you head far enough in one direction you can get back to the start. You can span the entire surface of a space with geodesics, and sure, they intersect, but intersecting at two separate points? That doesn't make even conceptual sense, generally. Will it travel along the same path as another geodesic while following the same formula as it with different constants, before moving off, despite the fact that defies the existence and uniqueness theorem proven for geodesics? Will it touch one point, wiggle around a bit, and touch the other despite that contradicting the whole definition of a geodesic? The only time, to my knowledge, that it could even conceivably happen is on a closed surface, but it doesn't matter there.
I suppose you could make similar arguments if you get onto weird spaces, like those with a hole or discontinuity in:

But they're not relevant to the subject under discussion. We're dealing with smooth spaces, and do you think mathematicians are incompetent? One of the first things that gets done is to try and prove existence and uniqueness, and it is proven that if you take a point and a vector (basically, direction), there is only one geodesic that passes through that point, so long as the space is smooth. You can go to good old wikipedia is you want a proof of that, and more evidence of how hard it is to provide accessible sources in this topic:
https://en.wikipedia.org/wiki/Geodesic#Existence_and_uniqueness

This is stupid. You plainly don't understand the subject given your claims about geodesics and Minkowski, I expect you'll be arguing against established theorems next post if you're following the same pattern, and all this could be avoided if you'd just google 'light travels along the shortest path' or 'light travels along geodesics' or would actually accept a source rather than just arguing for the sake of it.

Quote from: JackBlack on June 08, 2017, 01:56:39 AM

Because often people will misstate things because they don't understand the explanation.

The whole point of my statement has nothing to do with quantum physics and entirely to do with the fact "Light travels along geodesics."

No. It is more to do with your claim that light will take the shortest path between 2 points, which you have now effectively admitted is false and instead it can follow much longer paths.

What will it take for you to accept scientific fact?

For it to be shown to be scientific fact, with evidence backing it up.

Quote

Yes, your claims are ridiculous.
Remember what got us started here?
The claim that you could have a flat Earth in non-flat space.
That is the minkowski I am talking about. The one set up to make Earth flat, yet perfectly matching a round Earth in effectively flat space.

Uh, what? Minkowski space is not the only type of non-Euclidean space. It is one of an uncountably infinite variety. I just gave it as one example, I never said FET would work in it. It doesn't matter what 'the Minkowski' you're talking about is, there's only one Minkowski space.

Yes, my bad, I meant non-Euclidean space, not Minkowski.

You were effectively claiming FE BS would work in it. I pointed out an objection to it, something which apparently wouldn't work, which you dismissed and said it would still work, that of the path of light.

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Then how can it be the shortest distance between 2 points when it continues past it?

This also shows another difference between the geodesic and a straight line.

In Euclidean space, there is a single straight line between any set of 2 points (so 1 line for each pair, where some may be the same line) and if you take any 2 points on that line, you will be able to generate that straight line from it, and it will always be the shortest path.
But for non-Euclidean space, there can be many geodesics between a single set of 2 points, and if you take 2 points on that geodesic you would be able to get different geodesics than from the first pair. More importantly, not all of these are the shortest path.

A straight line goes on endlessly too, we're only concerned with a limited section. 'Light travels along geodesics,' does not mean 'light traverses all of every single geodesic regardless of whether or not it connects the two points in question.'

I asked if light would happily travel along it and you said it would.
Perhaps you should start getting your story straight.

If light can move along one bit, and then another and another and so on, why couldn't it just go straight along it?

As for "there can be many geodesics between a single set of 2 points," that is just completely wrong.

Not according to what you have said so far, at least some of it.
You accept that the geodesic is a line, not a line segment.

That line is thus a geodesic, and it has many points along it.

As such, you can have 2 points which many geodesics pass through.

Won't happen. The whole definition of a geodesic is "The shortest possible distance between two points."

Again, that only works if you are having it as a line segment, joining those 2 points.
So which is it?
Does the geodesic continue past the 2 points or does it stop at them?
You either lose the link to the shortest distance or you lose the link to the straight line.

Not all spaces are going to be like spheres, where if you head far enough in one direction you can get back to the start. You can span the entire surface of a space with geodesics, and sure, they intersect, but intersecting at two separate points? That doesn't make even conceptual sense, generally.

I never said it will happen in every possible case. I just pointed out it happens in some cases, like the example I provided.

Will it travel along the same path as another geodesic while following the same formula as it with different constants, before moving off

No. I am saying it will follow another geodesic.
Again, the example I provided, with an ellipsoid, using terms similar to Earth, one geodesic will start at the equator, go off to the north before reaching a maximum and heading back south, past the equator, reaching a minimum and heading back north to the equator, but not quite reaching the same point at the equator and instead being offset a little bit. That means there are 2 points on the equator along this geodesic (in fact there can be many many more, and this example actually has 3) These 2 points are basically right next to each other. A much shorter path connecting them is a completely different geodesic, one which just goes directly around the equator.

That is what I am talking about.
You have 2 points (both on the equator) with 2 completely different geodesics passing through them.

One of the first things that gets done is to try and prove existence and uniqueness, and it is proven that if you take a point and a vector (basically, direction), there is only one geodesic that passes through that point, so long as the space is smooth. You can go to good old wikipedia is you want a proof of that, and more evidence of how hard it is to provide accessible sources in this topic:
https://en.wikipedia.org/wiki/Geodesic#Existence_and_uniqueness

Yes, if you take a point and a vector, there is only one geodesic that obeys that. So what? I never said there wasn't.
If you take that same point and a different vector you get a different geodesic.

And guess what? Both of these can pass through another point.

This is stupid. You plainly don't understand the subject given your claims about geodesics and Minkowski, I expect you'll be arguing against established theorems next post if you're following the same pattern, and all this could be avoided if you'd just google 'light travels along the shortest path' or 'light travels along geodesics' or would actually accept a source rather than just arguing for the sake of it.

No. I do understand the subject. Yes, I used the wrong word, my bad.
The simple fact is I have provided an example of geodesics not being the shortest path between 2 points as there can be other, much longer paths, which are still geodesics, which pass through the same 2 points.
I even pointed out one of your references indicated that these "straightest" lines can actually be the longest.
I also gave examples of where light DOESN'T follow the shortest path and instead follows a much longer path.

But of course, you ignore all that and treat me like a moron.

While you are googling things, why not google some others like "Earth is flat", "vaccines cause autism", "mucus is the cause of all disease", "[insert religion here] is true" or any other BS you want and I'm sure you can find plenty of sources "backing" it up, some likely even saying they prove it.
I will not accept a source which just asserts something unless that is an observation.

No. It is more to do with your claim that light will take the shortest path between 2 points, which you have now effectively admitted is false and instead it can follow much longer paths.

Um, what? I said no such thing. It takes the shortest path between two points. A geodesic is the shortest path. Geodesics can go on endlessly, but you're the only one taking about light traversing the whole thing. I'm just saying that the route from the light source, to whichever destination you want, is a geodesic.
"Light travels along geodesics," is precisely the same claim as "Light takes the shortest path between two points." I cannot believe I need to keep saying this. To get from A to B, light travels along the geodesic connecting A to B. On smooth manifolds, this is the shortest path.
There is no contradiction until you start being an idiot and claiming "Light changes direction and switches between geodesics on a whim and also travels the whole curve despite the fact this would make it have to pass through solid objects."

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Then how can it be the shortest distance between 2 points when it continues past it?

This also shows another difference between the geodesic and a straight line.

In Euclidean space, there is a single straight line between any set of 2 points (so 1 line for each pair, where some may be the same line) and if you take any 2 points on that line, you will be able to generate that straight line from it, and it will always be the shortest path.
But for non-Euclidean space, there can be many geodesics between a single set of 2 points, and if you take 2 points on that geodesic you would be able to get different geodesics than from the first pair. More importantly, not all of these are the shortest path.

A straight line goes on endlessly too, we're only concerned with a limited section. 'Light travels along geodesics,' does not mean 'light traverses all of every single geodesic regardless of whether or not it connects the two points in question.'

I asked if light would happily travel along it and you said it would.
Perhaps you should start getting your story straight.

If light can move along one bit, and then another and another and so on, why couldn't it just go straight along it?

In theory, it can. In practise, generally light ends up interacting with objects. What are you talking about?! We're talking about light going from A to B, light source to destination. if you just want to focus on an arbitrary A or B, then yes it will more than likely be able to continue on.
My story's straight, you're the one completely changing the situation on a whim, in a way that makes no sense.

Again, that only works if you are having it as a line segment, joining those 2 points.
So which is it?
Does the geodesic continue past the 2 points or does it stop at them?
You either lose the link to the shortest distance or you lose the link to the straight line.

If you object to when I "treat you like a moron," then, seriously, do you genuinely not understand the concept of only traversing part of a curve? A line segment is still part of a line.

No. I am saying it will follow another geodesic.
Again, the example I provided, with an ellipsoid, using terms similar to Earth, one geodesic will start at the equator, go off to the north before reaching a maximum and heading back south, past the equator, reaching a minimum and heading back north to the equator, but not quite reaching the same point at the equator and instead being offset a little bit. That means there are 2 points on the equator along this geodesic (in fact there can be many many more, and this example actually has 3) These 2 points are basically right next to each other. A much shorter path connecting them is a completely different geodesic, one which just goes directly around the equator.

That is what I am talking about.
You have 2 points (both on the equator) with 2 completely different geodesics passing through them.

What?! You're now saying light will switch to a completely different geodesic despite the fact I have never even remotely claimed that? Seriously? You're just making things up now. Light travels along a geodesic from point A to point B, it doesn't switch between them and take whichever route you fancy. The problem here isn't me 'not keeping my story straight,' as you said, it's you just plain making things up.

Yes, if you take a point and a vector, there is only one geodesic that obeys that. So what? I never said there wasn't.
If you take that same point and a different vector you get a different geodesic.

And guess what? Both of these can pass through another point.

But not the same point. Again.

While you are googling things, why not google some others like "Earth is flat", "vaccines cause autism", "mucus is the cause of all disease", "[insert religion here] is true" or any other BS you want and I'm sure you can find plenty of sources "backing" it up, some likely even saying they prove it.
I will not accept a source which just asserts something unless that is an observation.

Have you even tried?! If you're not capable of basic source analysis I don't know what to say. if it helps the first source I can find saying light doesn't travel along geodesics is this:
http://youstupidrelativist.com/06QM/04Light/03Straight.html
So have fun with that, if that's the side you want to be on. The issue here is not with the statement "Light travels along with geodesics," it is with you being idiotic, and I'm not going to apologise for calling you that because quite frankly at this stage you have earned it. I have had better discussions with FEers. Your stance seems to be "All sources are wrong unless they agree with me and I'm not even going to try to check a fact for myself." You are making things up and acting as though it's an inconsistency with what I'm saying, making stupid claims (eg: "Because lines, which contain line segments, continue endlessly there's no way they include the shortest distance between two points." Given that a straight line is a geodesic this is literally what you said) and then relying on straw men.

You are rejecting scientific fact. This is no conspiracy theory, this is not 'vaccines cause autism,' this is established, accepted scientific fact and if you would even try to verify it for yourself you will easily be able to, especially if you have even the slightest grasp of how to examine the credibility of sources. You are rejecting scientific fact apparently just because it hurts your ego, and you're relying on constructing straw men rather than

Is there a single source you would accept? Answer that, at least.

Quote from: JackBlack on June 08, 2017, 04:32:25 AM

No. It is more to do with your claim that light will take the shortest path between 2 points, which you have now effectively admitted is false and instead it can follow much longer paths.

Um, what? I said no such thing. It takes the shortest path between two points. A geodesic is the shortest path. Geodesics can go on endlessly, but you're the only one taking about light traversing the whole thing. I'm just saying that the route from the light source, to whichever destination you want, is a geodesic.
"Light travels along geodesics," is precisely the same claim as "Light takes the shortest path between two points." I cannot believe I need to keep saying this. To get from A to B, light travels along the geodesic connecting A to B. On smooth manifolds, this is the shortest path.
There is no contradiction until you start being an idiot and claiming "Light changes direction and switches between geodesics on a whim and also travels the whole curve despite the fact this would make it have to pass through solid objects."

No. They are not the same thing.
If "light travels along geodesics", then it is capable of going on forever (barring something getting in the way) along the geodesic, meaning it can reach a point after taking a path much longer than the shortest path.
So no, THEY ARE NOT THE SAME!
There can exist a geodesic upon which 2 points lie where that geodesic is not the shortest path connecting them.
How many times do I need to say this?

I am not suggesting it magically jumps between them. I am saying there exists multiple geodesics which share 2 points.

That is an entirely separate issue, where instead of just taking the shortest path from a source to a detector it can bounce of a bunch of mirrors and end up taking a much longer path, where the path consists of (baring slight curvature of space due to gravity) straight lines and reflection/refraction/diffraction.

In theory, it can. In practise, generally light ends up interacting with objects. What are you talking about?! We're talking about light going from A to B, light source to destination. if you just want to focus on an arbitrary A or B, then yes it will more than likely be able to continue on.
My story's straight, you're the one completely changing the situation on a whim, in a way that makes no sense.

Well initially the discussion was on have a light source (like a laser pointer) and shine the light, how will it go, where I suggested it would follow the curvature of space (as I was ignoring the distortion of space time due to gravity) and you instead said it would follow a geodesic going from point A to point B.

I'm not completely changing the situation on a whim.

If you object to when I "treat you like a moron," then, seriously, do you genuinely not understand the concept of only traversing part of a curve? A line segment is still part of a line.

I object to you treating me like a moron because you ignore what I say, acting like I am saying something significantly different and then just refuting the pathetic strawman you set up.

Yes, a line segment is part of a line.
Which is a geodesic, the line segment or the line?
If it is the line, then it isn't the shortest distance between 2 points. Instead it would merely contain a section which can be the shortest distance between 2 points.

What?! You're now saying light will switch to a completely different geodesic despite the fact I have never even remotely claimed that?

No. Not switch.
I am saying the light can travel along a geodesic, like you claim, continuing along it, like you agreed, at reach a particular point.
I am additionally saying that there can be a shorter route (another geodesic) between these 2 points.

Light travels along a geodesic from point A to point B, it doesn't switch between them and take whichever route you fancy. The problem here isn't me 'not keeping my story straight,' as you said, it's you just plain making things up.

No, that would be you making things up, to pretend I said things I didn't.

THERE CAN BE MULTIPLE GEODESICS CONNECTING POINT A TO POINT B! (at least based upon what you have said so far)
DO YOU UNDERSTAND THAT?

I am not having the light magically switch between them. I am having the light continue along one which isn't the shortest distance between the 2 points.
That is not a difficult concept to understand.

Quote

Yes, if you take a point and a vector, there is only one geodesic that obeys that. So what? I never said there wasn't.
If you take that same point and a different vector you get a different geodesic.

And guess what? Both of these can pass through another point.

But not the same point. Again.

They can both pass through the same point, as is in the example I already gave, which you just ignored.

The uniqueness is that for a given point and vector you will have a single geodesic.
That doesn't go against what I said at all.

You can take 2 points, and 2 vectors and potentially get 2 geodesics which go through both points.

Have you even tried?! If you're not capable of basic source analysis I don't know what to say. if it helps the first source I can find saying light doesn't travel along geodesics is this:
http://youstupidrelativist.com/06QM/04Light/03Straight.html

Yes, I have tried looking.
The best I can find, which comes remotely close to "proving" it just takes the shortest path is for the specific example of refraction where they have the shortest path matching that predicted by wave theory.

You can also try to be selective in what you want your source to say.
For example, this one makes no mention of geodesics and instead says light follows the curvature of space:
https://docs.google.com/presentation/d/1XbO0eb6tAJ-l-BZUhUA2mjUjVKIiBX0XBXIwQvrNDS8/edit#slide=id.p73
Now can you find one which explicitly states that light doesn't follow the curvature of space or spacetime?

The issue here is not with the statement "Light travels along with geodesics," it is with you being idiotic, and I'm not going to apologise for calling you that because quite frankly at this stage you have earned it.

No, I haven't.
I haven't been idiotic in any way.
I demanded you back up your claims and pointed out inconsistencies with them and/or reality. That is not being idiotic.
What would be idiotic is if I just accepted your claims without thinking.

Meanwhile you continually misrepresent my arguments or just outright ignore them.
So who is really being idiotic here?

You are making things up and acting as though it's an inconsistency with what I'm saying, making stupid claims (eg: "Because lines, which contain line segments, continue endlessly there's no way they include the shortest distance between two points." Given that a straight line is a geodesic this is literally what you said) and then relying on straw men.

And there you go making a strawman of me yet again.
You were not saying the geodesic contains a segment which is the shortest distance between 2 points. You said the geodesic is the shortest distance between 2 points. That would make it a line segment.
I also pointed out that as they continue on indefinitely you can have 2 points on a geodesic where the distance along that geodesic is not the shortest distance between the 2 points, and that is a claim you are yet to refute. Instead you pretend I said something completely different, with light jumping between various geodesics or having magic ones.

You are rejecting scientific fact.

No. I'm rejecting your baseless claims which you are yet to back up in any rational manner.

if you would even try to verify it for yourself you will easily be able to

I did, and found nothing to actually verify it.

especially if you have even the slightest grasp of how to examine the credibility of sources.

I don't care about how credible someone deems a source to be.
I care about evidence and rational explanations, not baseless assertions.

You are rejecting scientific fact

Again, it is your baseless claim. You are yet to show it is a fact.

and you're relying on constructing straw men rather than

No, that would be you who has repeatedly failed to address the point I am actually making and instead are pretending I am saying something completely different.

Is there a single source you would accept? Answer that, at least.

I already did answer that. I will accept a source which actually proves it rather than asserts it.
And that requires more than just showing that in some cases it holds as does other methods.

Is there a single source you would accept? Answer that, at least.

Not really. I once gave JackBlack a link to a CERN study that said they once made such a good vacuum that they couldn't detect any particles inside, trying to convince him that a perfect vacuum isn't theoretically impossible to produce and maintain, and may even be achievable with sufficient technology. He thought the study might be wrong or something.

Quote from: Jane on June 08, 2017, 05:21:11 AM

Is there a single source you would accept? Answer that, at least.

Not really. I once gave JackBlack a link to a CERN study that said they once made such a good vacuum that they couldn't detect any particles inside, trying to convince him that a perfect vacuum isn't theoretically impossible to produce and maintain, and may even be achievable with sufficient technology. He thought the study might be wrong or something.

No. I didn't say the study was wrong, I said your conclusion on it was.
Not being able to detect a particle doesn't mean no particle.
Remember, all it takes is a single particle in it for it to no longer be a perfect vacuum.

You then tried appealing to magically cutting the vacuum into smaller pieces and saying that should be a perfect vacuum as it wouldn't have any particles in it.

I want to see if I'm following terms, since as near as I can tell a lot of this argument is semantics.  Please let me know if and where I am wrong.

If I understand correctly--let's take Earth as an analog for now (and pretend it's a perfect sphere for sake of argument).  For any given two points on the surface, barring antipodal points, there is exactly one great circle that contains those two points.  The shorter segment of that great circle between those two points would be a geodesic, and also the shortest path between the points.  I'm guessing the longer path between the two points (i.e. the other way around the great circle) would also be a geodesic (?) but of course not the shortest path.  Light would go both ways around the circle--and of course this wouldn't mean much on the surface of Earth, but in a spherical space-time it seems at least theoretically that would mean light could be going from A to B along two geodesics, but only along one shortest path.

Antipodal points would have two equal-length geodesics connecting them, meaning in theory you could see the same distant object at the same point in time, 180 degrees apart.  But other than that, it feels like in order to have more than one "shortest path" you'd need, as I think Jane alluded to at some point, some kind of very irregular space-time geometry.

I guess I'm just trying to clear this up for myself...I can't tell if you two's disagreement is over something fundamental or if it's mostly technicalities and semantics.

My more fundamental question is why the shortest path.
As far as I can tell, Jane was originally defining the geodesic as the shortest path, so only the section of the great circle between the 2 points.
I want to know why it wouldn't follow the other path as well.

For the exact definition, I can find some things indicating the geodesic is just the shortest path, just the segment between the 2 poitns and others indicating it continues past that and can also be the longest line between the 2 points (which makes no sense unless there is something else restricting it like a vector, which there is in some definitions/explanations I have found)

When they are antipodal they have infinitely many.

However, this great circle does not hold for all.
A simple case is a triaxial ellipsoid. (i.e. a sphere flattened in 2 directions). In this case instead of a great circle, the geodesic will not quite reach the same point on the "equator" and can thus fall short.
This means there will be some cases with numerous geodesics connecting 2 points.

But perhaps a more fundamental issue was what got us here in the first place, trying to make a metric so Earth is flat in non-flat space.
I noted that light should follow the curve of space, and thus if you were to shine a light parallel to the surface of this "flat" Earth in non-flat space (baring significant gravity), it should follow the curve of space and thus follow the surface of Earth instead of the observed going significantly off the surface.

This raises the question of how will light behave? Will it follow the curvature of space (only following geodesics in Minkowski space) or will it follow a geodesics everywhere, and the more fundamental question of why?
And that also raises the issue of if light doesn't follow the curvature of space then what constitutes "flat", especially as Jane claims these geodesics are the equivalent of straight lines and thus at least in my mind a "flat" surface should be composed of geodesics, and there should be other properties connecting these "flat" surfaces to these "straight" lines akin to Euclidean space.

Also, with this more general idea of a geodesic rather than a simple shortest path, it does at least appear to follow the curvature of space (or space time).

Quote from: Definitely Not Official on June 08, 2017, 06:08:04 AM

Quote from: Jane on June 08, 2017, 05:21:11 AM

Is there a single source you would accept? Answer that, at least.

Not really. I once gave JackBlack a link to a CERN study that said they once made such a good vacuum that they couldn't detect any particles inside, trying to convince him that a perfect vacuum isn't theoretically impossible to produce and maintain, and may even be achievable with sufficient technology. He thought the study might be wrong or something.

No. I didn't say the study was wrong, I said your conclusion on it was.
Not being able to detect a particle doesn't mean no particle.
Remember, all it takes is a single particle in it for it to no longer be a perfect vacuum.

You then tried appealing to magically cutting the vacuum into smaller pieces and saying that should be a perfect vacuum as it wouldn't have any particles in it.

Lol that is not what you said. You did question the validity of the research, I remember you said something about not entirely trusting what a PhD researcher had to say about it. I don't want to bring this discussion back up, because it's off topic.

This is just stupid. Let's focus on what really matters: your inability to accept reliable sources and accepted scientific fact. I am tired of having to repeat the same old facts (eg: "The line is the geodesic. Light travels along the geodesic. At no point have I said light traverses the entire length of the geodesic,") when you're just ignoring them.

Yes, I have tried looking.
The best I can find, which comes remotely close to "proving" it just takes the shortest path is for the specific example of refraction where they have the shortest path matching that predicted by wave theory.

You can also try to be selective in what you want your source to say.
For example, this one makes no mention of geodesics and instead says light follows the curvature of space:
https://docs.google.com/presentation/d/1XbO0eb6tAJ-l-BZUhUA2mjUjVKIiBX0XBXIwQvrNDS8/edit#slide=id.p73
Now can you find one which explicitly states that light doesn't follow the curvature of space or spacetime?

I'm not saying it doesn't. Like I pointed out before, the curvature of spacetime is basically given by the geodesic. Geodesics generalise the notion of a straight line to non-Euclidean space. In Euclidean 'flat' space a straight line is defined by the absence of curvature. When space 'curves,' you need a better way to measure it. Hence, geodesic. If geodesic is the generalisation of flat, it ought to be pretty intuitive that it gives the curvature of the spacetime it's in. Will this need to be repeated again or are you going to listen this time?

No. I'm rejecting your baseless claims which you are yet to back up in any rational manner.

They're not 'my' claims, again, scientific fact. If you had actually looked this up you'd have seen professors and published textbooks and countless scientists will happily say this. If you're just objecting that you don't understand the proof then bad luck, the universe doesn't cater to your ego, quantum physics and relativity are not easy, get over it.

Hi,

Thank you for your explanation. I can't say that I completely understand the principles and theories but I will read more about what you said. However, I don't understand why the horizon on the moon appears so close....I mean I know the moon it's smaller, but I think it's not normal to appear so close.
And I try to figure out how people can drink or eat in space, there is no gravity, no direction, everything it's floating! I'm very sure that I can't drink water in horizontal position. The open connection between nose, ear and throat allows for the exchange of fluids I suppose that's the reason we tilt our head when we drink or eat???

Lol that is not what you said. You did question the validity of the research, I remember you said something about not entirely trusting what a PhD researcher had to say about it. I don't want to bring this discussion back up, because it's off topic.

That was questioning the press release and a claim of a PhD researcher. That is not questioning the research itself or the evidence provided.

This is just stupid. Let's focus on what really matters: your inability to accept reliable sources and accepted scientific fact. I am tired of having to repeat the same old facts (eg: "The line is the geodesic. Light travels along the geodesic. At no point have I said light traverses the entire length of the geodesic,") when you're just ignoring them.

Why not focus on what actually matters rather than your pathetic slander?
That light WILL NOT always travel along the shortest path between 2 points.
Or if you like, the less important one of there can be 2 geodesics connecting 2 point.

Or the more important point which originally got us to this argument, for this "flat" Earth in non-Euclidean space, will light follow the curvature of space and thus travel parallel to this "flat" Earth, or will it take a different path?

You aren't repeating the same old facts. You are repeating claims and contradicting yourself.

I'm not saying it doesn't. Like I pointed out before, the curvature of spacetime is basically given by the geodesic.

BULLSHIT!
That is what got us on this path I the first place.
I stated that light should follow the curvature of space and thus should follow this "flat" Earth.
You then countered claiming it wouldn't and would take the shortest path.

Here is the quote from you:

Quote

I think the biggest issue is how light behaves, which is fundamentally appealing to 3D.
For a spherical universe, light should travel along the surface, effectively bending with it as that is what a "straight" line would be.
But in reality, it doesn't. So not even this model matches reality.

Yep, that's one of the mechanisms. Theoretically you could answer that with non-Euclidean space just as easily, the shortest possible distance between two points, which light takes, could get weird then.

I raise a significant issue with this "flat" earth in non-flat space (I know, I said spherical when in reality the third dimension wouldn't be spherical, but that is irrelevant) indicating that light should follow this "flat" surface, i.e. follow the curvature of space.
You then objected indicating that you could have it still match reality with light not following this "flat" surface by having more complex geometry and that light actually follows the shortest possible distance.

Geodesics generalise the notion of a straight line to non-Euclidean space. In Euclidean 'flat' space a straight line is defined by the absence of curvature. When space 'curves,' you need a better way to measure it. Hence, geodesic. If geodesic is the generalisation of flat, it ought to be pretty intuitive that it gives the curvature of the spacetime it's in. Will this need to be repeated again or are you going to listen this time?

It didn't need to be repeated this time.
Perhaps you should start actually reading what I am saying?

If light travels along geodesics, and geodesics define what constitutes a "flat", then light will travel along the surface of this "flat" Earth in non-Euclidean space. This is not what happens in reality, instead light will "bend" away from or towards this surface (in a predictable manner depending upon its orientation and position relative to the surface, effectively the same as treating the surface as a sphere and having the light follow a straight line) (where the distortion due to gravity is irrelevant due to how small it is).

Quote

No. I'm rejecting your baseless claims which you are yet to back up in any rational manner.

They're not 'my' claims, again, scientific fact. If you had actually looked this up you'd have seen professors and published textbooks and countless scientists will happily say this. If you're just objecting that you don't understand the proof then bad luck, the universe doesn't cater to your ego, quantum physics and relativity are not easy, get over it.

Again, you are yet to show it is scientific fact and I have shown examples which completely refute this "fact".
I have also seen plenty of sources (including ones like professors and countless scientists) quite happy making other baseless claims based upon not quite understanding something, like claiming that Beer-Lambert's law only holds if you don't have shadowing of some particles by others, while in reality that is required for the law.

I have also pointed out contradictions which you have simply ignored.

You've pointed out your misunderstandings and straw men which I got tired of repeating the responses to (Eg: bringing up mirrors). You are either lying or have no knowledge of basically anything relating to geodesics, and you're simultaneously insisting you know it better than a multitude of scientists despite being unable to provide even one reputable person that believes light does not travel along geodesics. I'm done, there's no discussing with arrogance.

what about fights from N America to Tokyo  (Japan) - do they fly west to oblivion!
or the reverse??
Follow the money! .............
« on: September 19, 2014, 08:33:13 AM »
I am not convinced that the Earth is a ball, but I am also not convinced that it is flat either. I am still in between trying to make sense of all of this. There are things that don't make sense to me with both models. The Antarctica issue is one of my questions. I have read some other threads about it, but none have given me answers that convince me.

The flat Earth model says that there is an ice wall that is 150' high that no one can pass, some even say it is guarded by the military. If it is guarded, what proof is there of it being guarded? That is an enormous area to protect, even if there were guard posts only every 10 miles, there would be 7,800 guard posts. There would be some evidence of this. Why is it that there are no ice wall guards talking about there experiences there? Or soldiers from the military talking about spending time in Antarctica? Or military families members telling people that their son is stationed in Antarctica?

How do you explain that you can take an expedition to the South pole? http://www.polar-quest.com/trip/fly-to-the-south-pole/ That is just one company that offers trips to Antarctica, there are others. If this area was guarded by the military wouldn't they prevent people from coming there?

Also, if the ice wall surrounds the Earth, it would have a circumference of about 78,000 miles since 78,000 miles is the circumference of the flat Earth. But Antarctica has only about 11,000 miles in coastlines. That is an enormous difference that anyone who sails around Antarctica would notice. Many people have been to Antarctica over the past several hundred years, many people have sailed around it and anyone can go there now. So if the Earth is flat how is it that no one notices that the coastline of Antarctica is so much longer than they expected?

Some people explain this by claiming that the ice wall and Antarctica are two different things, okay, fine, then where is Antarctica on a flat Earth map? Why is it that there is a South pole on Antarctic that you can go see, taking a  compass with you to verify that it really is the Southernmost point on Earth? Why is it that you can sail around Antarctica from the Australian side and be on the South American side? Shouldn't you be able to sail from Antarctica in a certain direction and arrive at the ice wall?

Now all that being said, I of course haven't been to Antarctica or sailed around it and I don't know anyone who has. So all the stories and photos online could be fake, conspiracy, etc etc... But this is one of the main areas that I am stuck on in accepting the flat Earth model and so far no one has explained it well enough that I am convinced.
 Logged

Hi,

Thank you for your explanation. I can't say that I completely understand the principles and theories but I will read more about what you said. However, I don't understand why the horizon on the moon appears so close....I mean I know the moon it's smaller, but I think it's not normal to appear so close.
And I try to figure out how people can drink or eat in space, there is no gravity, no direction, everything it's floating! I'm very sure that I can't drink water in horizontal position. The open connection between nose, ear and throat allows for the exchange of fluids I suppose that's the reason we tilt our head when we drink or eat???

Part of it may be that it is a completely unfamiliar scene which you can't easily process.
But the most significant part is likely what you said, it is smaller. Another part is that the cameras were chest mounted (so lower).

You can get a rough idea of how far away the horizon is by making a right angle triangle.

If r is the radius of the object, and h is your eye height, and d is the distance between your eyes and the horizon, you can construct a right angle triangle.
One side is r, which goes from the centre of the surface at the horizon.
This has a tangent (so a right angle) with a section of length d which goes to your eye (or the camera).
You then have the final line going from your eye back to the centre and it has a length of (r+h).

That means you get the following relation:
(r+h)^2=r^2+d^2
Thus r^2+2*r*h+h^2=r^2+d^2
Thus d^2=2*r*h+h^2.

This is actually where they get the 8 inches per mile squared crap from.
If you note h is going to be tiny compared to r and thus 2*r*h will be much larger than h^2, this simplifies to d^2=2*r*h.
Thus h=d^2/(2*r).
So if you take d to be in miles, r to be in miles you end up (for Earth) with h=d^2/7918 (with units it would be h=d^2/7918 miles.
To convert that to inches it would become h=8.0020201536 d^2 inch/mile squared.

But back to the issue at hand.
For Earth, it has a radius of 6371 km. The average eye height would be between 1.5 and 1.8 m.
So lets use 1.5. This gives (still leaving out the tiny h^2 part):
d^2=2*6371 km *1.5 m =2*6371 km * 0.0015 km=19.113 km^2
Thus d=4.37 km.

Now for the moon. I will still use the 1.5 m.
The moon's radius is 1737 km.
That means d^2=2*1737 km * 1.5 m=2*1737 km * 0.0015 km=5.211 km.
Thus d=2.28 km. That is roughly half the distance.

So the horizon should appear much closer on the moon.

Another factor which may contribute at times is your eyes trying to find a reference.
In some photos you can see Earth, this is similar to being on Earth and looking at the moon.
So it is possible your eyes/brain may interpret this Earth as being the same size as the moon when it is actually much larger. This means it will treat everything in the picture as smaller than it is, making the horizon seem much much closer.

This can also work in reverse with your mind using the horizon as a judge of size and thus make Earth appear much larger.

Another contributing factor which we can use to judge distance in some extent is how blurry something appears.
If you look at a mountain which is very far away it will appear blurry due to having to pass through so much atmosphere.
This doesn't happen on the moon due to the lack of any significant atmosphere, which can again trick your mind into thinking everything is really close.

As for the last point.
I'm fairly confident I can drink water in almost any position.
The only sometimes challenging part is getting it into my mouth. (try pouring water into your mouth from a glass while you are upside down).
While sick I have been lying in bed, drinking water while horizontal, so it is quite possible to do that.
We typically tilt our head when we drink to help guide the water in.
With a camel back (or hydration bladder) I don't bother tilting my head at all except to get it, which can sometimes mean tilting my head down.

In space, a 0g environment, the hardest part will remain the same, getting the water in your mouth. However that is only really a problem if you drink out of glasses. If instead you drink out of what is effectively a compressible bottle, letting you squirt or suck the water into your mouth, there is no problem.

An exception may apply for some medical conditions.

You've pointed out your misunderstandings and straw men which I got tired of repeating the responses to (Eg: bringing up mirrors). You are either lying or have no knowledge of basically anything relating to geodesics, and you're simultaneously insisting you know it better than a multitude of scientists despite being unable to provide even one reputable person that believes light does not travel along geodesics. I'm done, there's no discussing with arrogance.

You were the one using straw men, not me. You were the one completely ignoring what I was saying and instead pretending I said something completely different.
My problem is not with understanding, it is not accepting your baseless claim. You are the arrogant one here, and yes, there appears to be no discussing with it, as evidenced by you continually ignoring what I said and pretending I said something completely different.

And yes, using mirrors, which are perfectly fine in quantum mechanics, with them reflecting waves which can then interfere and cause diffraction patterns and the like. So what is wrong with using mirrors?
It makes perfect sense when dealing with light as a wave, not when trying to make light magically take the shortest path which would allow it to go past the mirror and to the detector instead of bounce off the mirror, bounce of another to come back and then get through the gap in the half silvered mirror.

It also makes sense with most of what I have found out about geodesics, with them being based upon vectors and being smooth.
In this case the light starts travelling along one geodesic, hits the mirror which causes it to be reflected and travel along another geodesic. It then hits another mirror which causes it to travel along yet another geodesic allowing it to get to the detector.

This also matches geodesics following the curvature of space (or space time), with the light following the curvature of space or space time rather than magically taking the shortest path. Sure, you can try to appeal to it following a geodesic which is also the shortest path between any 2 given points, such as source to mirror 1, mirror 1 to mirror 2 then mirror 2 to detector, but quantum mechanics doesn't really care about the mirrors. They don't interact with the light as a particle and thus the wave function continues.

Then again, you did complain about light deciding to switch between geodesics. Is this what you meant by that, or was that just a straw man?

, I've seen the original video when they recorded the so called 'mirage' , but I can't find it anymore.

That's what appear to be called a 'mirage', but I really doubt. Evan if you set a camera and record a video for a week or more, the perception over horizon distance will change because of the weather condition. We all experience sometimes fog or mist and we can't see 1 meter in front of us. This would be the case ,especially, on the sea shores because of the evaporation phenomenon so I would say that the air is denser, the denser the air the closer the horizon line. The water will evaporate in two cases: if it's warm, hot or if it's windy ( I can see this during the winter after rain, if it's dry for few days the water from my chair disappears ). These are facts we experience here on earth. Now, regarding to the moon, I think the horizon line should appear at a greater distance because there is no atmosphere, so there is no obstruction. Also there are no pictures of the stars taken from the moon in the first mission. As an explanation they say the earth is much brighter than the moon and that's the reason the stars fades, however in the videos, pictures presented by NASA it doesn't look so bright. I remember when I was a child I used to watch the sky and when the weather it was good the number of the stars was greater. While I was away in the country side the sky was mesmerizing....so many stars. But I can't say the same now because I barely see few stars.

In regards to drinking water in space, again I have doubts. 
I'm sure I cannot drink water while in horizontal position, I would chock same would happen if I would try to drink water while upside down. In my vision, in vacuum the water will float, it won't flow. The water doesn't know which direction should go, and because the pharynx it is commune for both respiratory and digestive system our water it's more likely to go about any direction.
https://www.quora.com/Is-it-safe-to-drink-water-while-laying-flat-on-a-bed

''Is it safe to drink water while laying flat on a bed?
7 Answers
Marcus Druckman
Marcus Druckman
Answered 16 Feb 2016
No, it can cause water to enter the eustachian  tubes, which lead to the middle ear, and if the water cannot leave, you will get an ear infection. The same goes for the sinuses (though the water would have to be swallowed wrong/get ino your nose for it to reach your sinuses). So don't drink in bed if you're sick, have allergies, or anything that may cause inlamation/congestion, otherwise you risk infections.
Only if you don't want to take it to your nose. By drinking water in a lying position the water enters the wind pipe (trachea) rather than the esophagus hence the choking and asyphixia'' From quora, and I agree with these answers.

So water takes a round shape in vacuum, but our body is about 50 - 75% water....our organs would go quite round I think, the skin won't keep everything tight.

Another interesting fact is that while we cannot dive into the deepest waters, we can go in space. If we are born on a spinning ball as it is said then how comes they cannot feel the spinning effect?

...
In regards to drinking water in space, again I have doubts. 
I'm sure I cannot drink water while in horizontal position, I would chock same would happen if I would try to drink water while upside down. In my vision, in vacuum the water will float, it won't flow. The water doesn't know which direction should go, and because the pharynx it is commune for both respiratory and digestive system our water it's more likely to go about any direction.
https://www.quora.com/Is-it-safe-to-drink-water-while-laying-flat-on-a-bed

''Is it safe to drink water while laying flat on a bed?
7 Answers
Marcus Druckman
Marcus Druckman
Answered 16 Feb 2016
No, it can cause water to enter the eustachian  tubes, which lead to the middle ear, and if the water cannot leave, you will get an ear infection. The same goes for the sinuses (though the water would have to be swallowed wrong/get ino your nose for it to reach your sinuses). So don't drink in bed if you're sick, have allergies, or anything that may cause inlamation/congestion, otherwise you risk infections.
Only if you don't want to take it to your nose. By drinking water in a lying position the water enters the wind pipe (trachea) rather than the esophagus hence the choking and asyphixia'' From quora, and I agree with these answers.

So water takes a round shape in vacuum, but our body is about 50 - 75% water....our organs would go quite round I think, the skin won't keep everything tight.

Another interesting fact is that while we cannot dive into the deepest waters, we can go in space. If we are born on a spinning ball as it is said then how comes they cannot feel the spinning effect?

I just tested it,
I can drink water when I am in a horizontal position, and also when I am upside down.

You do not feel the spinning effect is easy to explain:
For one we can only feel the change of speed (acceleration) and because the earth is spinning at a constant speed, we can not feel any acceleration.
And second, what we could feel is the centrifugal force. But if you calculate the quantity of that force you will see it is not big.
I did the calculation at it comes to a force of 3N for a 100kg object. That is equivalent to 300g. And that is calculated at the equator.
And as we "feel" this force constantly since birth, we do can not recognize it.

Drinking in multiple positions is also easier when using a straw.

I've seen the original video when they recorded the so called 'mirage' , but I can't find it anymore.

That's what appear to be called a 'mirage', but I really doubt. Evan if you set a camera and record a video for a week or more, the perception over horizon distance will change because of the weather condition.

Yes, as the weather conditions change, the distance you can see to the horizon can change.
Refraction will change it a small amount, and can allow more distant things which should be hidden by the horizon to come partially into view.
However the bottom is still hidden. This would not happen on a flat Earth. On a flat Earth you would be able to see it all.

There are also conditions where the atmosphere prevents you from seeing the horizon.
In this case instead of a nice clear horizon you get a blurr (or just a white fog or the like).
That is what a "horizon" would always look like on a flat Earth unless you are seeing the edge of Earth. It would always be a blur, not a clear line.

Now, regarding to the moon, I think the horizon line should appear at a greater distance because there is no atmosphere, so there is no obstruction.

That would only be the case if the moon was flat as well, but it isn't.
Also, the atmosphere can work both ways.
It can obstruct the horizon, making it a blur. It can also cause refraction, making it appear further away or allowing you to see things that should be hidden by the horizon.

Without an atmosphere you wont have the horizon get blocked or made into a blur, and without an atmosphere you wont get refraction allowing you to see things which should be hidden.
So on the moon, with it being much smaller than Earth, the horizon would be much closer.

Also there are no pictures of the stars taken from the moon in the first mission. As an explanation they say the earth is much brighter than the moon and that's the reason the stars fades, however in the videos, pictures presented by NASA it doesn't look so bright.

Yes, it doesn't look bright. That is because of the exposure time of the film. They set the exposure time so that Earth would be decently exposed to make it so you could see Earth and various details on it. That means the stars will be too dark to be captured on the film.
If they had the exposure set to capture the stars then you would see no details of Earth, it would just be a bright spot.

You can try this yourself if you can manually set the exposure on a digital camera. Find some place you can see stars, then set the exposure for that and take a photo. Then hold up a nice illuminated object (preferably with some detail, illuminated with a flash light or the like, a nice bright one), and take the shot again), with the same exposure setting. See what the bright object looks like. Now adjust the exposure to set it for the bright object so you can take a picture of the bright object in detail, and see what happens to the stars.

I remember when I was a child I used to watch the sky and when the weather it was good the number of the stars was greater. While I was away in the country side the sky was mesmerizing....so many stars. But I can't say the same now because I barely see few stars.

Yes, in the country you can see quite a few stars, unless there are clouds blocking it.
In the city you have serious light pollution.
This is from all the bright lights in the city. This can scatter off the molecules in the atmosphere (and water droplets and particulates) and make the sky appear brighter than it should. This can cause you to not be able to see the stars.

In regards to drinking water in space, again I have doubts.
I'm sure I cannot drink water while in horizontal position, I would chock same would happen if I would try to drink water while upside down.

I have no doubts.
I am sure I can drink water while horizontal or upside down. I have drunk water while horizontal, I don't remember if I have when upside down.

In my vision, in vacuum the water will float, it won't flow. The water doesn't know which direction should go, and because the pharynx it is commune for both respiratory and digestive system our water it's more likely to go about any direction.

The vacuum is not the issue, you being in free fall would be the issue.

Water doesn't need to know which way to flow, you body forces it down your esophagus while swallowing.

https://www.quora.com/Is-it-safe-to-drink-water-while-laying-flat-on-a-bed
''Is it safe to drink water while laying flat on a bed?
7 Answers
Marcus Druckman
Marcus Druckman
Answered 16 Feb 2016
No, it can cause water to enter the eustachian  tubes, which lead to the middle ear, and if the water cannot leave, you will get an ear infection. The same goes for the sinuses (though the water would have to be swallowed wrong/get ino your nose for it to reach your sinuses). So don't drink in bed if you're sick, have allergies, or anything that may cause inlamation/congestion, otherwise you risk infections.
Only if you don't want to take it to your nose. By drinking water in a lying position the water enters the wind pipe (trachea) rather than the esophagus hence the choking and asyphixia'' From quora, and I agree with these answers.

Try to get your information from scientific sources rather than sites where any moron can answer.

Especially when you just cherry pick an answer to suit your agenda.

For example, what was wrong with this answer:

Yes, you can drink water hanging upside down by your ankles if you want, if you are careful and don't get any in your lungs then you will be fine.
The hazard comes from the time when clean water was rare and aspirating bacterial infected water into your lungs could cause an infection, your stomach can handle a few bacteria, your lungs are less resistant.

Or here is a crazy idea: Try it yourself.
Go get a glass and a straw, lie down, and drink from the straw. See what happens.
Then, try it upside down.

Also remember, if you are in a 0g environment, your body wouldn't have to overcome gravity trying to push the water into your nose.

So water takes a round shape in vacuum, but our body is about 50 - 75% water....our organs would go quite round I think, the skin won't keep everything tight.

Again, the issue is the absence of gravity. Surface tension will pull water into a spherical shape.
This also happens to some extent on Earth.

But we are not just a water filled skin bag.
We are made of cells. These cells have walls (well membranes) which hold them in shape. They also have an extracellular matrix and an internal "skeleton" like structure composed of fibres, which hold the cells in shape and the extracellular matrix holds the cells to other cells.

If we had to rely upon our skin to hold us in shape we would be a skin covered puddle on the ground.

If your body can hold its shape on Earth, overcoming both surface tension and gravity, what makes you think it couldn't do the same in free fall where it just needs to overcome surface tension?

Another interesting fact is that while we cannot dive into the deepest waters, we can go in space.

Yes. That is because of the pressures involved.
Going into space we are going into a negative pressure environment relative to what we normally have. We will maintain this with a positive pressure.
This is quite stable to hold.
In order to hold a positive pressure inside a vessel, you just need strong walls and a good shape (round).
This is because the pressure inside is trying to push everywhere out, and if it is round, this is just causing the shape to try and expand.
In order to lose containment the shape needs to break and release the pressure inside. This requires ripping the container apart.

Holding negative pressure is a completely different issue.
This suffers from what is known as buckling instability.
With this, instead of having a greater pressure inside trying to push the walls out, you have a greater pressure outside trying to push the wall in.
This means you no longer need to rip the walls apart, you just need to fold them or crush them.

There are a few simple examples I can think of.
One is a sheet of paper.
See how much force is required to rip a sheet of paper, i.e. hold the top, and attach weights to the bottom. See how much weight it takes to rip it apart. That is akin to how much force it takes to fail due to containing positive pressure.
Now do kind of the opposite. Hold it at the bottom and attach weights to the top and see how much weight it takes to make the paper bend over. That is akin to how much force it takes to fail due to containing negative pressure (or having positive pressure outside).
If you would like a slightly more valid test, you can try various shapes of the paper, but for a real decent one you need hydrostatic pressure (same in all directions) on a roughly spherical or round shape).

Some other things you can try is a drink container.
You can start the test with some soft drink like coke, shaking it up and seeing just how much pressure is inside.
See if you can blow into it and have it break or even significantly deform.
Now see if you can suck air out of it and crush it. Unless it is a very good drink container, it should be quite easy to crush just be sucking the air out.

But there is another factor as well, and that is the pressures involved.
You can never get below 0 pressure.
The atmosphere has a pressure of 1 atm, roughly 1 bar, or 100 000 Pa. (this is because there is roughly 10 000 kg of atmosphere for each m^2 of surface.
Even going to a perfect vacuum you would only get that down to 0.
That means at most you have 100 000 Pa of pressure to deal with (the difference between internal and external pressure).
You will never need to construct a chamber designed for space that can handle any greater pressure unless you are planning on pressurising it more such that the inside is above atmospheric pressure.

But there is no limit to how great a positive pressure can be (well there might be some where the laws of physics starts to break down, but you will run into serious issues long before then).
And as you are going into water with a density of roughly 1 g/ml instead of up into air with a density of roughly 0.0012 g per ml, the change in pressure will be much faster. (the compressability, or decompressability of air also factors into it)
In air, you need to go all the way to space, and you still don't get a difference of 1 atm, but it is quite close to it.
In water, you need to go down 10 m.
This is because for air, you need over 100 km to have the 10 000 kg of air weighing down on you. (assuming the density remains constant at 0.0012 g/ml (1 ml is 1 cm^3) rather than drops relative to the pressure, that is 1.2 kg/m^3 and thus for a 1m^2 area, you need a column of air that is over 8 km high to get the 10 000 kg.
In water, you need 10 m (it is incompressible, at least at "normal" pressures, and thus its density would remain at roughly 1 g/ml or 1000 kg/m^3 and thus for a 1m^2 area you need 10 m to get 10 000 kg), to get an increase of 1 atmosphere.

Thus as a fair comparison, you should be dealing with space and exploring the great depths of 10m.

If you were to go 1 km down, then you will get an increase of roughly 100 atmospheres, so the pressure difference would be 100 atmospheres, so now your container, instead of needing to withstand a pressure difference of 100 000 Pa, it needs to withstand a difference of 10 000 000 Pa.
So going down has pretty much everything going against it.

If we are born on a spinning ball as it is said then how comes they cannot feel the spinning effect?

You kind of answered your own question there. It is somewhat akin to why can't I taste my own tongue?
You were born with that and have grown up with it, thus your body is calibrated to it so it wouldn't be able to feel it as it doesn't have the required reference.

Another great example is being dizzy. Go and spin around a lot and have your body slightly acclimatise to that. Then stop, it still feels like you are spinning even though you are not.
Your body isn't a perfect sensor and can easily be fooled by things like that.

You can do the same with colours. Stare at an image long enough then look at a white wall, see what you "see".

But perhaps a far more important issue is just how insignificant this turning is.
You are turning at a rate of 1 revolution per day. The acceleration required for this at the equator is roughly 0.03 m/s^2. Gravity provide 9.8 m/s^2.
That is so small it isn't funny.
If you weighed 100 kg, the force from gravity would be roughly 1000 N, while the apparent force due to the rotation would be 3 N. That is equivalent to a mass of roughly 300 g.

To give you a comparison, clothes can weigh several kg.
So this force from spinning would be akin to the weight difference of taking off some light clothing.

You are not going to feel that.

If you have issues with how long that reply is, please pick a single point to discuss at a time.

Well then we can easily say that cold also it will not affect us? So we just ignore the spinning and the gravity, yet people are easily affected by high or low temperatures, high or low air pressure, we cannot dive in the depths of our oceans, but just simply ignore all these aspects while in vacuum? It looks like our bodies would feel so much better is vacuum!
But you know what I would really like to see? A picture of a satellite taken by someone from earth. There are so many out there, at least that's what they say, there are even websites with satellites maps. So anyone with a good camera maybe can take a picture???

Well then we can easily say that cold also it will not affect us?

No, we have significant variations in temperature. However, people are typically more comfortable with slightly colder temperatures in winter and warmer ones in summer.

So we just ignore the spinning and the gravity,

No. People are effected by gravity. It causes them to fall.
We ignore the spinning primarily because it is virtually nothing.

we cannot dive in the depths of our oceans, but just simply ignore all these aspects while in vacuum?

I already explained why. With the pressure, the vessel would get crushed. In the depths of the ocean you are dealing with a massive pressure difference which will crush the contained.
In space, you are dealing with a relatively tiny pressure difference which needs to rip the container apart to make it fail.

It looks like our bodies would feel so much better is vacuum!

Not necessarily our bodies, due to other effects like a lower boiling point of water, but the containers we build.

But you know what I would really like to see? A picture of a satellite taken by someone from earth. There are so many out there, at least that's what they say, there are even websites with satellites maps. So anyone with a good camera maybe can take a picture???

You mean like the plenty we have of the ISS?


Photographing satellites is quite difficult, especially if you want any other than the ISS. Most are in fairly high orbits, over a few hundred km high and most are no more than a few m across, and are moving at quite high speeds.

For the ISS, you are trying to take a picture of something that is 100 m long 400 km away (when directly overhead) and moving at a speed of 7.67 km/s.
In a second it moves over 70 times its length.

For smaller satellites it is more like over 700 times its length.

So you really think anyone would be able to just get a camera (maybe their phone) point it at the sky and take a picture?

Quote from: İntikam on May 31, 2017, 06:09:16 AM

Quote from: tomato on May 31, 2017, 05:36:43 AM

Hi, I'm a self-taught physicist - obviously raised around RET - but I'm open to anything. Actually, I'd like to contribute some mathematically rigorous and testable arguments for FET that could hold water in a scientific light.

Are there any FET topics, say, that have readily verifiable results, but no one has done the math or the physics involved in them yet?

I don't know FET well, so please help me out, with its basic principles, and with which ones might lead me to answers.

FET depends on two fact phsical claim: "The earth is flat, the earth is stationary". The earths to be stationary is a main principle of FET, oppositely our fool admins claim in wiki. He already a controlled opposite, but we are not. You can trust me.

Diffusion is the most strongest argument about there is a doom.

Mass gravity is debunked by us but there is atmospheric stringence causes accelerate to objects.

You can get radio signals in Istanbul from New York and this proves the earth is flat. Also you can get radio signals in Sydney from London. It is tecnically imossible if the earth is a spinning ball.

Our obversations, also calculations on any of round map proves the earth is flat.

You can examine my working about that issues and other by a looking at:

https://www.theflatearthsociety.org/forum/index.php?topic=66236.0

Frankly, draw a velocity diagram depends on balance of gravity and centrifugal forces, by altitude. After look to the clouds, nothing is moving. This is a basic en strong proof for a physicist.

Radio 570 WNAX
Welcome to WMCA 570am - New York | The Mission AM 570 WMCA - , NY
KLAC - AM 570 LA Sports Los Angeles, CA
570 KLIF - KLIF - AM 570 - Dallas, TX - Listen Online
570 KVI Radio Station 570 kHz, AM - Seattle, United States ...


Explain to me if you can, how these radio stations, can broadcast on the same frequency and not interfere with each other, on the flat Earth?

It goes unanswered, so I am refreshing.