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The issue at hand is that nobody remembered to specify which frame of reference to use when considering the problem: the Sun, the Earth, or an observer outside them both.

I think the start of the issue at hand is that LeGrande believes that there is no difference between being orbited and spinning in a two_body+light model. I say that there is a difference - in a two_body+light model, if the sun moves after emitting light, it's obvious because the light's path will maintain a record for 8.3 minutes of where the sun was even though it's moved. But if the sun doesn't move and instead the earth rotates 2.1 degrees, the sun's light will still be on a path originating from the sun's position.

The problem is that LeGrande's view just doesn't line up with science or reality and when applied to things that are a little farther away then the sun, his view is obviously wrong - which is why he keeps refusing to answer simple questions like this:

For an observer on earth at an instant in time who looks east and sees a stationary and bright planet above the equator, a planet that is 12 light hours away, how far displaced from it's actual position will be the apparent position? Will the planet really appear in the east when it is really in the west?

You see, since he's said that the sun will (per the above scenario) appear 2.1 degrees behind its actual position since the earth rotates 2.1 degrees in the 8.3 minutes it takes sunlight to reach the earth, and since he's said that if it was farther the angle would be greater, the only answer he can say to my question is that "Yes, the 12-light hour away planet would appear in the east at the moment it was really in the west." But you see if such was the case, astronomers all over would have to know about it and there would be some scientific documents describing it. But neither him nor I have been able to find any such documents. And he keeps refusing to apply his own reasoning to simple thought experiments that I or others have provided - and there seems no logical reason that he would refuse such - unless he knows that he's wrong and refuses to admit it.

Thanks,

-Jesse

PS: Regarding your suggestion that I could consider LeGrande a troll: He generally doesn't behave like a troll. He presents himself as smart and as knowing things that most other people don't know. Some of them aren't true and yet he tells them as if they are true, and refuses to admit it when he finds out he's wrong.

Sorry, dudes, I've had insomnia and not slept all night. Let me take a brain-fog stab at it. The problem is not that the light diverges from its path, it is that the rotation of the earth means that the observer is no longer seeing each ray of light from the same angle as he would have, absent the earth's rotation. And so I think LeGrande is suggesting that, just like a mirror, you get an optical illusion (so to speak). the human eye traces light back to its *apparent* source.

Two possibly complicating factors here: one is the problem at sunrise and and sunset, when the motion of the earth is parallel or antiparallel to the direction of the light, this divergence is minimized. Also, the earth is not a sphere, it is an oblate ellipsoid (i.e. a beachball with an elephant sitting on it, not a football).

Also, you have the issue of what the ancients called "lack of stellar parallax" -- the distance between the stars and the earth is so great, one can travel anywhere one likes on Earth without affecting the apparent relative positions of the stars. I'm just a little too tired to decide if something analagous would kick in here.

Cheers!

mrjesse - I think the start of the issue at hand is that LeGrande believes that there is no difference between being orbited and spinning in a two_body+light model.

That is correct. They are equivalent.

mrjesse - I say that there is a difference - in a two_body+light model, if the sun moves after emitting light, it's obvious because the light's path will maintain a record for 8.3 minutes of where the sun was even though it's moved. But if the sun doesn't move and instead the earth rotates 2.1 degrees, the sun's light will still be on a path originating from the sun's position.

You are contradicting yourself mrjesse. You have already said that if the light from the sun stops, that you will continue to see the sun move across the sky for 8.3 minutes and 2.1 degrees (in an Earth spinning model). mrjesse - Of course the sun will still appear to move at 2.1 degrees per 8.3 minutes after it is shut off. (LG I added the last part 'after it is shut off' for clarification.

The problem is that LeGrande's view just doesn't line up with science or reality and when applied to things that are a little farther away then the sun, his view is obviously wrong - which is why he keeps refusing to answer simple questions like this:

For an observer on earth at an instant in time who looks east and sees a stationary and bright planet above the equator, a planet that is 12 light hours away, how far displaced from it's actual position will be the apparent position? Will the planet really appear in the east when it is really in the west?

I am confused. I have answered the question many times. You even refer to my answer in your next paragraph.

You see, since he's said that the sun will (per the above scenario) appear 2.1 degrees behind its actual position since the earth rotates 2.1 degrees in the 8.3 minutes it takes sunlight to reach the earth, and since he's said that if it was farther the angle would be greater, the only answer he can say to my question is that "Yes, the 12-light hour away planet would appear in the east at the moment it was really in the west." But you see if such was the case, astronomers all over would have to know about it and there would be some scientific documents describing it. But neither him nor I have been able to find any such documents. And he keeps refusing to apply his own reasoning to simple thought experiments that I or others have provided - and there seems no logical reason that he would refuse such - unless he knows that he's wrong and refuses to admit it.

First, as you clearly state, I put it in bold, I have answered your 12 light hours away planet question and yet you insist that I haven't. I don't believe that you are intentionally lying, what are you thinking mrjesse?

As for your astronomy question, the simple answer is that Astronomers don't generally use the Earth as a frame of reference, they use the Stars. Have you ever used a Star Chart? Can you guess why they use the Stars (especially after our discussion)?