Camera near the speed of light

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SUMMARY

The discussion centers on the feasibility of taking a photograph while traveling at speeds approaching the speed of light (c) on a spaceship. Participants conclude that if two individuals are on the same spaceship moving at near-light speed, they can indeed take pictures of each other without experiencing any relativistic effects relative to one another. However, an observer on a stationary planet would witness significant relativistic effects if attempting to photograph the spaceship. The conversation emphasizes the principles of relativity, particularly that observers in inertial frames do not perceive changes due to their relative motion.

PREREQUISITES
  • Understanding of Einstein's theory of relativity
  • Familiarity with the concepts of inertial reference frames
  • Knowledge of relativistic effects such as time dilation and length contraction
  • Basic principles of photography and light behavior
NEXT STEPS
  • Study Einstein's Special Relativity and its implications on motion and observation
  • Explore the concept of inertial frames and how they relate to relativistic physics
  • Investigate the effects of relativistic speeds on light and photography
  • Examine thought experiments involving relativistic scenarios, such as the twin paradox
USEFUL FOR

Students of physics, astrophysicists, photographers interested in the effects of speed on light, and anyone curious about the implications of relativity in practical scenarios.

  • #31
DaveC426913 said:
Correct.

But the other point being: since from their point of view it is us speeding through the universe at near c, and we don't have trouble taking picture of each other here on Earth... therefore moving at near c does not affect the ability to take pictures.


.

Is this because the speed of light is constant no matter what inertal refrence frame its observed from? Meaning, We see them moving near c, they see us moving near c, but both of us agree on the value of c regardless of our velocity compared to c.
 
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  • #32
Integral said:
Consider this. Objects very distant from the Earth are observed to have velocities near the speed of light with respect to earth. So with respect to these distant objects the Earth is traveling at a relativistic velocity.

Now, can you take a picture?

interesting, what are these objects? and at what distance are they from us?
 
  • #33
tkav1980 said:
Is this because the speed of light is constant no matter what inertal refrence frame its observed from?
Yes.
tkav1980 said:
Meaning, We see them moving near c, they see us moving near c, but both of us agree on the value of c regardless of our velocity compared to c.
No. Other way around. Our velocity when we compare it to c is always c. Their velocity when they compare it to c is always c.

But yes, we both agrgee that c wrt us is c.

nitsuj said:
interesting, what are these objects? and at what distance are they from us?

Distant galaxies billions of ly away near the edge of the observable universe.
 
  • #34
DaveC426913 said:
Yes.

No. Other way around. Our velocity when we compare it to c is always c. Their velocity when they compare it to c is always c.

But yes, we both agrgee that c wrt us is c.

Hey, I really appreciate you taking the time to explain things. I think we both said the same thing when talking about velocites as they relate to c, but i tend to put things on paper so to speak that most people have a hard time understanding. It's simply the way i type.

I should have said from our point of view they are moving at x % of c, however they will measure c as c. in essence from their point of view our measurements don't mean anything since we are measuring from a different inertial frame. Still no matter who measures it, no matter what frame, c is always c.
 
  • #35
For example, suppose you are standing on the side of a road, with a baseball catcher's mitt.
Standing on the back of a flat bed truck, moving toward you at 40 mph, I throw a baseball to you with, relative to me, a speed of 60 mph. By Newtonian theory, the baseball would have a speed, relative to you, of 60+ 40= 100 mph. By relativity, the baseball's speed relative to you would be very slightly less than 100 mph but the difference would be too small to measure.

If I were to shine a light toward you with, relative to me, speed c, by Newtonian theory, the speed of that light, relative to you, would be c+ 40. But, according to relativity, the speed of that light, relative to you, would still be c. That is what is meant when we say that the speed of light, relative to any observer is c.
 
  • #36
HallsofIvy said:
For example, suppose you are standing on the side of a road, with a baseball catcher's mitt.
Standing on the back of a flat bed truck, moving toward you at 40 mph, I throw a baseball to you with, relative to me, a speed of 60 mph. By Newtonian theory, the baseball would have a speed, relative to you, of 60+ 40= 100 mph. By relativity, the baseball's speed relative to you would be very slightly less than 100 mph but the difference would be too small to measure.

If I were to shine a light toward you with, relative to me, speed c, by Newtonian theory, the speed of that light, relative to you, would be c+ 40. But, according to relativity, the speed of that light, relative to you, would still be c. That is what is meant when we say that the speed of light, relative to any observer is c.

That part I understand. No matter whes your velocity is or my velocity is, light will always be measured at c. c, when it comes to the motion of ANY observer, is constant, its not an additive or multiplicative(sp?) property.

This may be a bit out there, but why is that? Is there a known mechanism for this?
 
  • #37
tkav1980 said:
This may be a bit out there, but why is that? Is there a known mechanism for this?

It is a postulate. It is not shown; it is supposed.

"If this were the case, what would we see?"

Turns out, if it were the case, what we should see describes exactly what we do see. SR is a spectacularly accurate model of how our universe seems to work. That makes it probably right. More accurately, it makes it right enough that we can proceed with a subsequent century (so far!) of excellent science without it ever failing us.
 
  • #38
DaveC426913 said:
Distant galaxies billions of ly away near the edge of the observable universe.

Yea that's what I woulda guessed.

And that's comparable to the spaceship traveling at nearly c flying by a planet? (rhetorical)
 
  • #39
nitsuj said:
Yea that's what I woulda guessed.

And that's comparable to the spaceship traveling at nearly c flying by a planet? (rhetorical)

Yes.
 
  • #40
DaveC426913 said:
Yes.

wow,

So with billions of LY inbetween us and the distant galaxy, doesn't expanding space account for the majority of the "speed".

I find it pretty funny to think that some galaxies out there travel at near c speeds, through space. ? what would propel them to those speeds?

But yup I hear you Dave, just like a spaceship, well comparable enough to draw conclusions as has been in this thread.

I may as well go back to reading Brian Greene.
 
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  • #41
nitsuj said:
doesn't expanding space account for the majority of the "speed".
It does. But the 'how' doesn't affect the 'what'.
 
  • #42
DaveC426913 said:
It does. But the 'how' doesn't affect the 'what'.

And I don't believe that. The difference between the to are immense.

So dave, I sure you believe then that galaxies can travel FTL, since the how doesn't affect the ?.
 
  • #43
nitsuj said:
And I don't believe that. The difference between the to are immense.

So dave, I sure you believe then that galaxies can travel FTL, since the how doesn't affect the ?.
I said nothing about FTL.

The point is, us moving at .99c (relative to some planet, say, Earth) and trying to take a picture - is identical to us stationary with Earth moving at .99c and trying to take a picture.

We can prove this to ourselves easily, because there are currently things that are moving wrt to us at .99c (which means we are moving .99c wrt them), so why would we suddenly be unable to use a camera?

So:

A spaceship traveling away from us at .99c will see us traveling away from them at .99c. That fact that they see us moving at .99c does not in any way affect us being able to take pictures with a camera.

A galaxy traveling away from us at .99c will see us traveling away from them at .99c. That fact that they see us moving at .99c does not in any way affect us being able to take pictures with a camera.
 
  • #44
DaveC426913 said:
I said nothing about FTL.

The point is, us moving at .99c (relative to some planet, say, Earth) and trying to take a picture - is identical to us stationary with Earth moving at .99c and trying to take a picture.

We can prove this to ourselves easily, because there are currently things that are moving wrt to us at .99c (which means we are moving .99c wrt them), so why would we suddenly be unable to use a camera?

So:

A spaceship traveling away from us at .99c will see us traveling away from them at .99c. That fact that they see us moving at .99c does not in any way affect us being able to take pictures with a camera.

A galaxy traveling away from us at .99c will see us traveling away from them at .99c. That fact that they see us moving at .99c does not in any way affect us being able to take pictures with a camera.

I think, actually accelerating a spaceship to nearly c is vastly different then saying well, some massive object out the is moving that fast (which there isn't) so it's all the same because it's relative.

My comment about galaxies traveling FTL has the same basis as your comment regarding galaxies traveling near c (space expanding/very long distances/very old galaxies), so I assumed you'd agree it's true.
 
  • #45
nitsuj said:
I think, actually accelerating a spaceship to nearly c is vastly different then saying well, some massive object out the is moving that fast (which there isn't) so it's all the same because it's relative.
It is vastly different in many ways, but it is not vastly different in a way relevant to the discussion.
 

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