Sun-Earth-Moon Gravity

That's what they do.Say that a lightning bolt strikes the ground about a mile in front of the train. To the person standing on the platform, the train will then pass directly over the point where the event happened. However, to the person in the train, if he's using his frame of reference, the spot at which the event happened remains the less-than-a-mile* in front of the train, even as the black spot on the ground travels toward him and passes directly under him.Added by edit:
*Taking into account length contraction.Edited by Chiroptera, : No reason given.

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I've done everything the Bible says, even the stuff that contradicts the other stuff! -- Ned Flanders

That's what they do.

That's not what they do. They measure to marks left by the lightning strikes. This is not where the light from the lightning strike was emitted.If the observer who takes the embankment as her reference-frame and the observer who takes the train as her reference-frame are able to measure to where the light from the lightning strike was emitted, they will wind up at the same point and this would not coincide with either mark.

Suppose that you are standing on the sidewalk, and you see a car approaching you. You see the tire blow out. The car doesn't stop, but continues by you. How do you describe the incident? You say, "The tire blew out at the corner over there," even though the flat tire is passing you right at that moment. Because you are describing the time and the position of the incident according to your reference frame.Now consider the man on the train. He notices the lightning strike the ground in front of the train. Now he notices the ground and the storm clouds are moving toward him, and knowing how far away he saw the lightning strike, how fast the ground-and-storm is traveling, and how fast light travels, he does some calculations and figures that the lightning struck a point about half a mile in front of the train. He continues to say, "The lightning struck the ground at a point about half a mile in front of the train, over there," even as the black spot on the ground in passing him.Now the lady on the platform sees that black spot isn't moving, and it is the train that is passing by the spot. In the same way, the driver in the car insists that the blow-out occurred in the tire five feet behind him, and it is you, on the sidewalk, who is passing by the tire.

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I've done everything the Bible says, even the stuff that contradicts the other stuff! -- Ned Flanders

Suppose that a murder occurs on the train. The person on the platform (somehow) notices it. The sheriff asks her, "Where did the murder occur?" She replies, "Three miles down the track." The sheriff is relieved because that is a different county and, even though the train, murderer and murder victim are passing him right that instant, the murder itself occurred in a different jurisdiction and isn't his responsibility.But, of course, the person on the train will answer, "The murder occurred in that compartment, 100 feet away." And he will continue to say this, because the murder occurred only 100 feet away from him on the train. This causes no contradiction because the person on the platform is discussing an event that occurred on a moving train when it was at a specific point in her reference frame.In the same way, the man on the train, seeing the lightning strike, will say that the lightning struck at a point half a mile in front of the train, even thought the incident occurred on a moving ground-and-storm and the moving ground carried the actual storm clouds and the black spot passed him.

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I've done everything the Bible says, even the stuff that contradicts the other stuff! -- Ned Flanders

I'm on a miles long moving sidewalk when the tire blows out right on top of the moving sidewalk. An hour later, the police ask me what happened and I point to a spot 5 feet in front of me on the moving sidewalk and say the tire blew out right there. The police, using my reference-frame, measure from that point to where the car stopped and can't believe how far the car traveled on a flat tire and what good condition the tire is in. Only problem is, the car didn't travel that far. Using my reference-frame does not represent the correct point where the tire really did blow. It represents a point in the past where the tire blew.

The problem is that people are asking questions with one coordinate system in mind, and the answers are being given in a different coordinate system. Questions need to be more specific, and answers need to be more specific. In relativity, one always has to have the frame of reference in mind. As you point out, answers become nonsensical when people mix up frames of reference.

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I've done everything the Bible says, even the stuff that contradicts the other stuff! -- Ned Flanders

The whole problem is there is on one true frame of reference and everything is in motion in that frame.There is no train reference frame or embankment reference frame.Measuring to a mark left by a lightning strike does not represent where the lightning strike occurred. It's just a mark made by the lightning strike and represents a point where the lightning strike occurred in the past. You cannot measure to it now.

Consider the murder on the train.The person on the platform, when asked where the murder occurred, will reply, "Several miles down the track." But when told they need to examine the body, she will answer, "Oh, well it occurred in the third compartment."In the same way, the man on the train, when asked where the murder occurred, will reply, "In the compartment 100 ft behind me." But if they make it clear they need to know in which jurisdiction the murder took place so they can charge the murderer properly, then the man, knowing that county lines are painted on the ground that is moving past him outside, will then say, "Oh, well then it happened in the other county a few miles back."See? Both people will give the same answers as long as it is clear what the questions really are and what the appropriate coordinate systems are to use.

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I've done everything the Bible says, even the stuff that contradicts the other stuff! -- Ned Flanders

No, the whole problem is that you think that there is one true frame of reference but there isn't.That isn't to say some frames of reference aren't more convenient for some problems than others, just that there is no absolute true frame of reference.

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I've done everything the Bible says, even the stuff that contradicts the other stuff! -- Ned Flanders

Measuring to marks left by a lightning strike, that no longer represent where the lightning strike occurred, to prove there are multiple frames of reference is weak at best, and to me, it is simply wrong.Thanks for your time.

It's wrong to me too, since what you wrote makes no sense whatsoever.Edited by Chiroptera, : Completely replaced post.Edited by Chiroptera, : typo

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I've done everything the Bible says, even the stuff that contradicts the other stuff! -- Ned Flanders

When we discussed cosmological distances we agreed that the distance to the galaxy cluster millions of light years away should be measured to where the light is emitted, not to where the galaxy cluster is now.When we measure the distance to the lightning strikes, we need to do the same; measure to where the light from the lightning strikes was emitted, not to where the lightning strike marks are now.The marks on the train and the marks on the embankment do not represent where the light from the lightning strikes emitted from, just as where the galaxy cluster is now does not represent where the light from the galaxy cluster emitted from.This might just make things worse, but here is an attempt at an example:Our train reaches from here to the galaxy cluster millions of light years away. The observer, train and galaxy cluster are in the same reference-frame. When the lightning strikes the train it leaves a mark on the train at a point in the train that is in the galaxy cluster. The observer is millions of light years from where the lightning strike leaves a mark on the train. After millions of years, the light finally reaches our observer and she decides to measure the distance to where the lightning strike originated. Should she measure to where the light was emitted, or should she measure to where the mark is on the train (i.e. to where the galaxy is now)?Edited by mpc755, : Trying a better example

I never agreed that we should do anything. I merely pointed out that when we measure the distance to a galaxy cluster, we are measuring the distance to where the light was emitted. How else can we make the measurement? We can only make the measurement based on what we see, and what we see is the point in space and time when the light was emitted.- But "where" and "when" the light from the lightning was emitted depends on the frame of reference in which you are making these measurements. In the ground's frame of reference, the light was emitted at the strike marks. So the strike marks indicate where the light was emitted. In the train's frame of reference, the strike marks are moving, and so, after some time, the strike marks are no longer at the point in space where the light was emitted.- This makes no sense whatsoever. All we can know about the galaxy and train is from the light (or other signals) that reach us from there. So this is going to determine to where we measure the distance. We cannot measure the distance to where the train is now, because we don't know where the train or the galaxy is now. Millions, even more, have passed since the events that we are observing now. The train and galaxy could be anywhere now. In fact, for all we know, the train and the galaxy don't even exist any more. We know nothing about the train or the galaxy now.

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I've done everything the Bible says, even the stuff that contradicts the other stuff! -- Ned Flanders

In the ground's frame of reference, the light was emitted at the strike marks.

No, the light was not emitted at the strike marks. The strike marks were made in the past and no longer represent where the light emitted from.If there is one thing any observer knows as fact, is that his reference frame is in motion and the marks in his reference frame have moved since the light from the lightning strikes made the marks.

so, after some time, the strike marks are no longer at the point in space where the light was emitted.

Exactly!

All we can know about the galaxy and train is from the light (or other signals) that reach us from there. So this is going to determine to where we measure the distance. We cannot measure the distance to where the train is now, because we don't know where the train or the galaxy is now. Millions, even more, have passed since the events that we are observing now. The train and galaxy could be anywhere now. In fact, for all we know, the train and the galaxy don't even exist any more. We know nothing about the train or the galaxy now.

Exactly! That is why measuring to the marks left by the lightning strikes makes no sense, because they might not even exist anymore and even if they do, do not represent where the light emitted from.

Sure they were, in the frame of reference of the strike marks themselves. In a frame of reference where the stike marks are not moving, then the strike marks aren't moving. Therefore, in that frame of reference, the strike marks remain exactly where the light from the strike was emitted.You really seem to be having trouble with a concept that really isn't very difficult.- Sure, but the point in space where they used to exist certainly exists. Just because a house burns down, we can point out the location where it used to be. So we can still use a reference frame where the strike marks were stationary; then the strike marks are associated with a definite position, a definite spatial coordinate, in that frame of reference.I'm beginning to suspect that you are having difficulty with the concept of coordinate systems. Either that, or you're a troll having us all on.

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I've done everything the Bible says, even the stuff that contradicts the other stuff! -- Ned Flanders