speed of energy transfer at relative velocity

quantum quack · 07-15-2005

Hopefully I wont make a total mess of this question.
It is associated with teh notion of absolute time and the possibility of a light clock being used to calculate the absolute velocity of that clock.

As we know light travels at 'c' and is invariant in it's speed to all observers regardless of the velocity of those observes. The assumption then is that the energy of that light is also invariant to all observers.

here's the scenario I have in mind:
On earth we have a light or heat source and an energy receptor, or should I say an object that increases in temperature over a given amount of time due to the projected energy of the light source.
Now for example we find that the receptor gains in temperature at a given rate when positioned on the surface of earth.
The question is :
1] How does the relative velcoity of the apparatus affect the rate of temperature increase of our receptor?

Say for arguements sake on earth the receptor gains 10 degrees in 10 minutes on earth.
Will it also gain 10 degrees in 10 minutes at say 0.8c.

remembering that the light is the same regardless of velocity of our frame but the frames time has slowed.
2] Does this mean that our receptor would get hotter quicker or slower or would the rate of energy transfer stay the same as it's velocity increases [ relative to it's own frame] ?

any thoughts would be welcome...

Little Bang · 07-15-2005

Say for arguements sake on earth the receptor gains 10 degrees in 10 minutes on earth.
Will it also gain 10 degrees in 10 minutes at say 0.8c.

That depends, if it is approaching the light source it would gain energy faster. If receding the exact opposite.

quantum quack · 07-16-2005

Quote:

Originally Posted by Little Bang

Say for arguements sake on earth the receptor gains 10 degrees in 10 minutes on earth.
Will it also gain 10 degrees in 10 minutes at say 0.8c.

That depends, if it is approaching the light source it would gain energy faster. If receding the exact opposite.

hmmm... why would a receptor gain energy faster. You may have missed the scenario fact that the light source and receptor are both sharing the same frame. say for example the source is projecting orthagonal to the vector of travel.

quantum quack · 07-16-2005

Maybe it's worth pointing out that the notion of a light clock being used to calculate absolute velocity is forbidden by SRT.

However what I am wishing to explore is an energy clock that involves the transfer of energy over time. Whether there is any practical use for it as a means of informing the observer of the relative velocity for his rest frame.

My guess that for this to be a valid notion it would violate SRT, and I wonder how this would be so?
Little bang, are you familiar with the light clock concepts?

adjective · 07-16-2005

I'm unsure what you're saying. The energy source, is it part of the frame? As in:

Suppose we have a focused laser. We point this at a thermometer. Now, for the first version, we'll assume the two remain stationary relative to each other. For the second version, are we simply taking that apparatus and having it move at a velocity (to take your example, .8c) relative to the initial apparatus? Or are we accelerating the thermometer toward the laser?

quantum quack · 07-16-2005

Quote:

Originally Posted by adjective

I'm unsure what you're saying. The energy source, is it part of the frame? As in:

Suppose we have a focused laser. We point this at a thermometer. Now, for the first version, we'll assume the two remain stationary relative to each other. For the second version, are we simply taking that apparatus and having it move at a velocity (to take your example, .8c) relative to the initial apparatus? Or are we accelerating the thermometer toward the laser?

I quickly drew this diagram to show what I mean....

As the apparatus changes it's velocity does it observe a change in the time it takes for the thermometer to gain 10 degrees?

assume that at a v= 0.2c it records 10 seconds for 10 degrees. Would the time be the same if a record was taken for 0.8c?

adjective · 07-16-2005

Yes. You mentioned light clocks--it's the same thing. Since light is constant for all frames, then over 10 seconds, regardless of velocity, the same amount of photons would strike the thermometer over a ten second period, thus the same amount of energy imparted on the thermometer.

quantum quack · 07-16-2005

Quote:

Originally Posted by adjective

Yes. You mentioned light clocks--it's the same thing. Since light is constant for all frames, then over 10 seconds, regardless of velocity, the same amount of photons would strike the thermometer over a ten second period, thus the same amount of energy imparted on the thermometer.

brilliant , thankyou, so to sum up because of lights invariance time is not dilated from the rest frames perspective.
How ever and there is always a however...from another slower frames perspective it would appear that the thermometer is either faster or slower in gaining it's ten degrees [ I am too tired to work out whether it is faster or slower ] The slower v frame would see a thermometer change it's rate of gain as the energy clock changed it's relative v.
again thanks....

Little Bang · 07-16-2005

From your diagram the rate would always be the same sense they are both in the same frame of reference. the velocity of the frame of reference would have nothing to do with rate of transfer.

UncleAl · 07-16-2005

Quote:

It is associated with teh notion of absolute time and the possibility of a light clock being used to calculate the absolute velocity of that clock.

You are grievously, tremendously, irreparably, massively, incredibly, ignorantly, empirically wrong already. You have no idea what the world is about. Do you stubbornly maintain this loathsome state or do you improve yourself?

Quote:

The assumption then is that the energy of that light is also invariant to all observers.