Length contraction of distant objects/space, etc

In summary: So if the object is at an angle to you, it will occupy an angle that is proportional to the cosine of the angle between the two vectors.
  • #1
coktail
118
1
If I am moving through space at a velocity that is a significant fraction of c, are all objects ahead of me in my path contracted in the direction of my travel for an infinite distance? In other words, are planets and stars from right in front of me to the edge of the known universe contracted as I move towards them?

What about once I'm past them? Do they remained contracted until I slow down?

Does this contraction decrease if an object is not directly in front of me, but off to the side a bit?

As always, thank you.
 
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  • #2
The Lorentz transformation is the equivalent of a rotation in ordinary space. It does not propagate at the speed of light; it is "instantaneous."

Compare, for example, this scenario: you are moving in a 2d plane that has no absolute coordinate system (no notion of north, south, east, or west) just what's ahead of you, what's behind, what's left and what's right. When you turn, all objects on this plane rotate as well, instantaneously as you do. If you have an object 5 miles ahead of you and you turn 45 degrees to the right, the object is then ~3.5 miles ahead of you and ~3.5 miles to your left.
 
  • #3
coktail said:
If I am moving through space at a velocity that is a significant fraction of c, are all objects ahead of me in my path contracted in the direction of my travel for an infinite distance? In other words, are planets and stars from right in front of me to the edge of the known universe contracted as I move towards them?
Yes.

What about once I'm past them? Do they remained contracted until I slow down?
Yes.

Does this contraction decrease if an object is not directly in front of me, but off to the side a bit?
It contracts along the axis parallel to your velocity vector.

As always, thank you.
 
  • #4
Thanks!

Does the entire universe (including space itself) in my path contract, or just objects?

Can someone please elaborate on "it contracts along the axis parallel to your velocity vector" for me? What I take this to mean is that an item at an angle to me would contract at an angle, but that may be totally wrong.
 
  • #5
If you're pointing in the x-direction, other objects will contract in the x-direction regardless of where they are.
 
  • #6
coktail said:
Thanks!

Does the entire universe (including space itself) in my path contract, or just objects?s
Yes, that is the crucial difference between Einstein's theory and Lorentz's theory: the distance between two objects contracts as well as the objects.

Can someone please elaborate on "it contracts along the axis parallel to your velocity vector" for me? What I take this to mean is that an item at an angle to me would contract at an angle, but that may be totally wrong.
I'm not sure what you mean by "contract at an angle". If you are at (0,0) in some coordinate system moving in the positive y direction, an object that, to a stationary observor, is a rectangle with vertices at (1, 1), (2, 1), (1, 4), and (2, 4), it will appear to you to occupy [itex](1, 1- \beta), (2, 1- \beta), (1, 4- \beta), (2, 4- \beta)[/itex].
 

FAQ: Length contraction of distant objects/space, etc

What is length contraction?

Length contraction is a phenomenon in Einstein's theory of relativity where an observer moving relative to an object will measure the object's length to be shorter in the direction of motion compared to its rest length. This effect is only noticeable at very high speeds, close to the speed of light.

How does length contraction work?

Length contraction occurs because as an object moves closer to the speed of light, its perception of time and distance changes. This is due to the fact that the speed of light is constant and the laws of physics are the same for all observers, regardless of their relative motion.

Does length contraction apply to all objects?

Yes, length contraction applies to all objects regardless of their size or composition. However, it is only noticeable at speeds close to the speed of light. At everyday speeds, the effect of length contraction is too small to be measured.

How is length contraction related to time dilation?

Length contraction and time dilation are two sides of the same coin. Time dilation refers to the slowing of time for an object moving at high speeds, while length contraction refers to the shortening of an object's length in the direction of motion. Both effects are a result of the laws of relativity and are closely related.

Can length contraction be observed in everyday life?

No, length contraction is only noticeable at speeds close to the speed of light, which is much faster than any object can travel in our everyday lives. However, it is a fundamental principle in modern physics and is essential for understanding the behavior of objects at high speeds and in extreme environments.

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