Seeing things in their past? You are full of beans!

[TrueBeliever37]

There is no time or distance at the speed of light.

Then how can you claim to believe C is a constant?

 

[TrueBeliever37]

Wrong. The length of the pen depends on the frame in which it is measured. In all cases, it was *physically measured*. The spacecraft brought out its ruler as it was passing by and measured right when the rule and the pen were lined up.

Ok - let's do another experiment. This time we all take identical pens with us on our trips. The pens measure 5 1/2" here on earth. Each ship reaches the speeds you want them to reach and then they measure the pens. What does each pen measure this time?

 

[Polymath257]

Then how can you claim to believe C is a constant?

This has been explained any number of times.

You do not seem to understand that a distance accurately and correctly measured to be 30 million light years in one frame can *also* be accurately and correctly measured to be, say 3 million light years in another frame. This would, in fact, be the case in a frame moving at 99.5% of the speed of light relative to the first.

In the frame where the distance is 30 million light years, light will take 30 million years to make the journey.

In the frame of that is going at 99.5% of the speed of light, the star is going 99.5% of the speed of light the other way ( I neglected to take that into account before...my bad). So, in addition to starting out a mere 3 million light years away, it is also moving at 99.5% of the speed of light. That means that the actual amount of time as measured by the spaceship will be .005*30 million=150,000 years. it would take 3 million years for the light to get to where the star was seen at the start.

 

[TrueBeliever37]

Who says? They are the accurate, correct measurements *for that reference frame*. The *physical* length of the pen depends on the relative speed of the pen and the measuring device.

No matter what speed you are moving at, identical pens will measure the same in all the ships. Those measurements will tell the real/true/accurate physical length of the pen.

I understand you can have some corresponding reference frame that will give you different answers.
But those answers still aren't the true physical length of the pen.

 

[Polymath257]

Ok - let's do another experiment. This time we all take identical pens with us on our trips. The pens measure 5 1/2" here on earth. Each ship reaches the speeds you want them to reach and then they measure the pens. What does each pen measure this time?

So, once again, we have 1 pen on the Earth, one pen on a spaceship going at 86% of c in one direction and one pen on a spaceship going at 86% of c in the other direction.

First, everyone sees their own pen as being 5 1/2" long.

Second, both spaceships see our pen as being 2 3/4" long. We also see the pens on the spaceships as being 2 3/4" long. (I am assuming the pens are aligned with the direction of travel here. If they are aligned perpendicular to the direction of travel, they will be seen as 5 1/2" long and will be seen as elliptical in cross section).

Finally, the two spaceships see the pens on the other spaceship as being .82" long. (Again, this assumes the pens are aligned in the direction of travel. If they are perpendicular, they would be measured as 5 1/2" long).

This is precisely the same result as I described before, by the way.

Once again, I am assuming that all parties involved can do the measurements with as much accuracy as desired and are completely correct).

 

[Polymath257]

No matter what speed you are moving at, identical pens will measure the same in all the ships.

Nope. See my previous post.

 

[TrueBeliever37]

So, once again, we have 1 pen on the Earth, one pen on a spaceship going at 86% of c in one direction and one pen on a spaceship going at 86% of c in the other direction.

First, everyone sees their own pen as being 5 1/2" long.

Second, both spaceships see our pen as being 2 3/4" long. We also see the pens on the spaceships as being 2 3/4" long. (I am assuming the pens are aligned with the direction of travel here. If they are aligned perpendicular to the direction of travel, they will be seen as 5 1/2" long and will be seen as elliptical in cross section).

Finally, the two spaceships see the pens on the other spaceship as being .82" long. (Again, this assumes the pens are aligned in the direction of travel. If they are perpendicular, they would be measured as 5 1/2" long).

This is precisely the same result as I described before, by the way.

Once again, I am assuming that all parties involved can do the measurements with as much accuracy as desired and are completely correct).

My bad on not seeing your post about identical pens being on all ships at same time.

But anyway, since they each see their own pen as being 5 1/2" long, that would be the true physical measurement.

 

[TrueBeliever37]

Nope. See my previous post.

You just said - First everyone sees their own pen as being 5 1/2" long. Now you are saying Nope to what I said.

 

[Polymath257]

Here's a couple of links that might be helpful:

Length Contraction

The last 3 have a pretty good description of what is going on.

 

[Polymath257]

My bad on not seeing your post about identical pens being on all ships at same time.

But anyway, since they each see their own pen as being 5 1/2" long, that would be the true physical measurement.

And each see the other pens as being *correctly* as a different length. ALL are correct physical distances.

In essence, you want to only measure lengths in the frame of reference where the object is at rest. This is often possible, but not always.

 

[Polymath257]

And each see the other pens as being *correctly* as a different length.

You just said - First everyone sees their own pen as being 5 1/2" long. Now you are saying Nope to what I said.

Yes, each sees their own pen as being the 5 1/2" length. Why do you consider that to be the 'true' length? The measurements from the other frames are just as *true* and *accurate*

 

[TrueBeliever37]

This has been explained any number of times.

You do not seem to understand that a distance accurately and correctly measured to be 30 million light years in one frame can *also* be accurately and correctly measured to be, say 3 million light years in another frame. This would, in fact, be the case in a frame moving at 99.5% of the speed of light relative to the first.

In the frame where the distance is 30 million light years, light will take 30 million years to make the journey.

In the frame of that is going at 99.5% of the speed of light, the star is going 99.5% of the speed of light the other way ( I neglected to take that into account before...my bad). So, in addition to starting out a mere 3 million light years away, it is also moving at 99.5% of the speed of light. That means that the actual amount of time as measured by the spaceship will be .005*30 million=150,000 years. it would take 3 million years for the light to get to where the star was seen at the start.

To me it is this simple. Whether you are looking at light traveling from the sun to the earth, or light traveling from alpha centauri to some planet 30 million light years away. You should be able to use the formula, Speed of Light = C = distance/time , to see how long it takes to travel that far.

You guys keep saying you believe speed of light is a constant, but you don't apply it that way.

You keep saying light years are distances, yet seem to always want to equate them to zero, no matter what the distance is.

It's been quite a few posts back, but what was it you were saying was instantaneous? I am going to hunt for the post.

 

[Polymath257]

To me it is this simple. Whether you are looking at light traveling from the sun to the earth, or light traveling from alpha centauri to some planet 30 million light years away. You should be able to use the formula, Speed of Light = C = distance/time , to see how long it takes to travel that far.

Yes, and you can use this formula in every valid frame (not a limiting one because such limiting ones are not valid).

You guys keep saying you believe speed of light is a constant, but you don't apply it that way.

We can apply it in every frame. If you go *between* frames, you will get nasty inconsistencies.

You keep saying light years are distances, yet seem to always want to equate them to zero, no matter what the distance is.

It's been quite a few posts back, but what was it you were saying was instantaneous? I am going to hunt for the post.

I mentioned the limiting 'frame' and what happens in that limit. But, again, there is no valid frame moving at the speed of light.

So let's first get things straight for the frames that *are* valid. Different frames will measure different distances and different time intervals. But when they watch light move, it always has the same distance/time.

 

[TrueBeliever37]

Yes, and you can use this formula in every valid frame (not a limiting one because such limiting ones are not valid).



We can apply it in every frame. If you go *between* frames, you will get nasty inconsistencies.



I mentioned the limiting 'frame' and what happens in that limit. But, again, there is no valid frame moving at the speed of light.

So let's first get things straight for the frames that *are* valid. Different frames will measure different distances and different time intervals. But when they watch light move, it always has the same distance/time.

How is it ok to use the formula to determine the time it takes to get from the sun to earth. But using it to determine how long it takes to get from a star to another planet any different?

Both are looking at time from a star to a planet.

It's just using a constant and a distance and determining a time. Why is it ok in one instance, but then off limits in the other? The speed of light is involved in both cases, what makes one limiting and the other not?

 

[TrueBeliever37]

Yes, each sees their own pen as being the 5 1/2" length. Why do you consider that to be the 'true' length? The measurements from the other frames are just as *true* and *accurate*

No they can actually take a ruler and measure the exact specific physical length. They might be able to use that information while using the other frame of reference, but it is not the true physical length. I think you know that, but it conflicts with your theory so you can't acknowledge it.

 

[Subduction Zone]

@Polymath257 have you seen the work of Mark Rober? He is an engineer and YouTuber that has made a "time globe". It mechanically does Lorentz Transformations. You can see it in this video:

 

[TrueBeliever37]

I mentioned the limiting 'frame' and what happens in that limit. But, again, there is no valid frame moving at the speed of light.
.

Then why are you able to use it for determining time from the sun to the earth? That involves movement at the speed of light.
Just like it does when I ask how long from alpha centauri to a planet 30 million ly away.

Use same frame of reference and solve both for me.

 

[Subduction Zone]

Then why are you able to use it for time from the sun to the earth? That involves movement at the speed of light. Just like it does when I ask how long from alpha centauri to a planet 30 million ly away.

The answer is "it depends". What frame of reference are you thinking about?

 

[TrueBeliever37]

The answer is "it depends". What frame of reference are you thinking about?

Another robotic answer. Doesn't even begin to answer the question I asked.

Use same frame of reference and solve both for me.

 

[Subduction Zone]

Another robotic answer. Doesn't even begin to answer the question I asked.

Use same frame of reference and solve both for me.

You asked a robotic question. What frames of reference do you want the problem solved in?