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

[Subduction Zone]

I understand that, but the limit is for the observers time.

That is the only way to do it. One has to be careful in applying the equations, one can get it backwards. In my frame of reference anything moving is experiencing time at a slower rate. As that object approaches the speed of light, relative to me, its time slows as I measure it.

Relativity made my head hurt when first exposed to it. I too thought that there was a "right time". There isn't. It only seems that way to you because one does not see anyone moving at relativistic speeds in one's world. That leads to a biased viewpoint of one's time being "right".

 

[TrueBeliever37]

The limit would be c. When you plug that number into the formula you get a zero in the denominator.

No it's the limit of something as you allow v to approach c.

 

[Thermos aquaticus]

No it's the limit of something as you allow v to approach c.

The observer never reaches the limit, so why keep asking about it?

 

[TrueBeliever37]

That is the only way to do it. One has to be careful in applying the equations, one can get it backwards. In my frame of reference anything moving is experiencing time at a slower rate. As that object approaches the speed of light, relative to me, its time slows as I measure it.

Relativity made my head hurt when first exposed to it. I too thought that there was a "right time". There isn't. It only seems that way to you because one does not see anyone moving at relativistic speeds in one's world. That leads to a biased viewpoint of one's time being "right".

Sorry but I am just trying to look at the math, and it doesn't look like you guys are applying the limit to the right thing.

 

[TrueBeliever37]

The observer never reaches the limit, so why keep asking about it?

Because you guys are applying the limit to the time for the photon, and I think it is the limit for the time of the observer, as he approaches the speed of light.

 

[Polymath257]

No I am looking at the formula you gave me and asking which time the limit is applying to?

OK, take two observers: observer A is on the earth. Observer B is going from the earth to the sun at velocity v.

The the observer time in the formula is the time for the journey as measured by a clock at rest with respect to A. The proper time in the formula is the time for the journey as measured by a clock on the ship (and hence, at rest with respect to B). Two clocks. They will measure different amounts of time.

No matter what v is, we will have

time for A = (time for B)/sqrt(1 -(v/c)^2 ).

This is the basic equation with observer time given by the time for A and with proper time give as time for B. Are we good so far?

Now, in the limit as v goes to c (so we look at ships going faster and faster, with the speed getting closer and closer to c), the time for the ship gets closer and closer to 0. So, the faster ship measures a smaller amount of time for the trip from the earth to the sun.

Also, as v gets closer and closer to c, the time for A (the time as measured by the earth) gets closer and closer to 500 seconds (8 minutes, 20 seconds).

So, the *limit* of the left hand side is 500 seconds.

The limit of the right hand side gives 0 on top and 0 on the bottom. This is a 0/0 form for a limit, which is indeterminate. BUT, because of the basic equation, we know that the value of this limit is 500 seconds: the time (as measured from the earth) for light to go from the earth to the sun.

BUT, since the time for B is going to 0, the proper time for a *photon* will be *this* limit, which is 0.

 

[Polymath257]

I agree it's the observer in the ship. As I said, if I was in a ship as I approached the speed of light, time would approach 0 for me relative to the light. But once again the light/photon would still be traveling at c and experiencing time and distance.

For higher speeds v, the observer on the ship experiences less time and less distance. As v-->c , both the distance and time *as experienced on the ship* go to 0. But the *ratio* goes to c.

 

[Subduction Zone]

Sorry but I am just trying to look at the math, and it doesn't look like you guys are applying the limit to the right thing.

You can't apply it to the photon. All you can do is to apply it so that you can tell how much time you see pass for an object as an observer. And as an observer you will see that the time that passes for an object approaches zero as the object approaches the speed of light relative to you.

Once again, there is no "proper time" there is only the time that you observe.

 

[Thermos aquaticus]

Because you guys are applying the limit to the time for the photon,

I thought we were talking about the observer? Are we bouncing between the observer and the photon again?

 

[james blunt]

Because you guys are applying the limit to the time for the photon, and I think it is the limit for the time of the observer, as he approaches the speed of light.

Notice how they do not discuss but instead try to gain objective control of your own thinking. They will not allow you to believe anything else other than what they tell you , you have got to accept their reality.

 

[Thermos aquaticus]

Notice how they do not discuss but instead try to gain objective control of your own thinking. They will not allow you to believe anything else other than what they tell you , you have got to accept their reality.

You are describing yourself again.

 

[james blunt]

You are describing yourself again.

How they try to turn everything around of the true reflection of themselves.

 

[TrueBeliever37]

OK, take two observers: observer A is on the earth. Observer B is going from the earth to the sun at velocity v.

The the observer time in the formula is the time for the journey as measured by a clock at rest with respect to A. The proper time in the formula is the time for the journey as measured by a clock on the ship (and hence, at rest with respect to B). Two clocks. They will measure different amounts of time.

No matter what v is, we will have

time for A = (time for B)/sqrt(1 -(v/c)^2 ).

This is the basic equation with observer time given by the time for A and with proper time give as time for B. Are we good so far?

Now, in the limit as v goes to c (so we look at ships going faster and faster, with the speed getting closer and closer to c), the time for the ship gets closer and closer to 0. So, the faster ship measures a smaller amount of time for the trip from the earth to the sun.

Also, as v gets closer and closer to c, the time for A (the time as measured by the earth) gets closer and closer to 500 seconds (8 minutes, 20 seconds).

So, the *limit* of the left hand side is 500 seconds.

The limit of the right hand side gives 0 on top and 0 on the bottom. This is a 0/0 form for a limit, which is indeterminate. BUT, because of the basic equation, we know that the value of this limit is 500 seconds: the time (as measured from the earth) for light to go from the earth to the sun.

BUT, since the time for B is going to 0, the proper time for a *photon* will be *this* limit, which is 0.

I agree with most of this.

But as you said the limit of the right hand side is 500 seconds: the time (as measured from the earth) for light to go from the earth to the sun.

So you can't just take that limit and then lower it even more to 0, that was why it was called the limit to begin with.

 

[TrueBeliever37]

Notice how they do not discuss but instead try to gain objective control of your own thinking. They will not allow you to believe anything else other than what they tell you , you have got to accept their reality.

I am going to approach it more like Einstein did, thinking on my own, not just believing what everyone else says or thinks.

Not saying I am an Einstein, just that I want to think things out myself.

 

[james blunt]

I am going to approach it more like Einstein did, thinking on my own, not just believing what everyone else says or thinks.

That is exactly what I did, I read some science and then questioned it, to come up with a different , seemingly better description.
Start with time, that is a good one, or what is space. Start anywhere really, from your first thinking you will develop other ideas.

 

[Thermos aquaticus]

I agree with most of this.

But as you said the limit of the right hand side is 500 seconds: the time (as measured from the earth) for light to go from the earth to the sun.

So you can't just take that limit and then lower it even more to 0, that was why it was called the limit to begin with.

The limit on one side is zero velocity with respect to the Earth. The other limit is a velocity of c relative to Earth. With zero velocity relative to the Earth you get 0 length contraction. At the other limit of c you get infinite length contraction so that there is no distance.

 

[Polymath257]

I agree with most of this.

But as you said the limit of the right hand side is 500 seconds: the time (as measured from the earth) for light to go from the earth to the sun.

So you can't just take that limit and then lower it even more to 0, that was why it was called the limit to begin with.

But, if instead of using the earth as the reference, you use some observer moving with respect to the earth, you get a different a different limit, which may be smaller. And, as the 'stationary' observer has speeds close to c (with respect to the earth), the limit is closer and closer to 0.

 

[Thermos aquaticus]

It may or may not help to revive the graph that describes length contraction vs. relative velocity.

The two limits, if I am understanding it correctly, are the x and y intercepts. The y intercept is 1.0. The x intercept is at c. At the y intercept there is no relative velocity and anything with the distance of 1 will still be 1. At the speed of light, c, anything with a length of 1 will now have a length of 0.

 

[TrueBeliever37]

The limit on one side is zero velocity with respect to the Earth. The other limit is a velocity of c relative to Earth. With zero velocity relative to the Earth you get 0 length contraction. At the other limit of c you get infinite length contraction so that there is no distance.

Hi Thermos, The limit wasn't for velocity, it was for time. As the v of the ship approached c

In the equation we were looking at, it was a limit for the observers time, as v of the ship approached c. Which turned out to be 500s per Polymaths calculation. Telling us that the limit for the time that the observer would record for that ship to get from earth to the sun, as it approached the speed of light, would be 8m and 20s. Exactly what we would expect, the same as the time for light to get from the sun to the earth.

 

[TrueBeliever37]

But, if instead of using the earth as the reference, you use some observer moving with respect to the earth, you get a different a different limit, which may be smaller. And, as the 'stationary' observer has speeds close to c (with respect to the earth), the limit is closer and closer to 0.

We were looking at the limit of time for the observer, as the v of the ship approached c. Is that the limit you are saying gets closer and closer to 0?