Lorentz tranformations and time slices

In summary, Lorentz transformations account for both time dilation and length contraction, causing the spatial axes to change in addition to the time axis. This means that the time slices for different observers will be distorted, with the entire space being distorted and not just the time axis. The warping is linear and can be represented by different basis vectors, but the transformation can get more complex in the "worst case" scenario.
  • #1
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I have a question about the way lorentz transformations work with respect to a 'block' view of the universe.

Take our universe as a 3d chart with 2 space dimensions and one time dimension (ignoring the other space dimension for simplicity). You chart it using some "god's eye view" reference frame, or just any single reference frame. So you end up with simultaneous events perpendicular to the time axis for any point in time. Each time slice is just a rectangle showing that moment in time (for the 'god-like' observer).

Now when you apply lorentz transformations for another observer, can you use that same chart? Is it true that the new observer just has a slightly angled time slice (due to the transformation) but still uses the same chart? So their time slices are stretched rectangles compared to the god-like observer?

Or do lorentz transformations change things so much that it would be impossible to represent the universe using a single 4d block (i.e. you'd need a different 4d block for each observer)?
 
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  • #2
Lorentz transformations account for time dilation AND length contraction, so not only is the time axis different according to observers in different inertial reference frames, but the spatial axes also changes. Perhaps this video might be helpful for helping you visualize:



So I think It's more of the latter suggestion, it's not just the time axis that is stretched relative to an outside "god-like" observer, but in fact, the entire space that is distorted.
 
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  • #3
Thanks that is a good video.

I guess my question is about the way a time slice deforms in the 'worst case'. For the 3d space-time example it would appear the time slices get transformed from a regular rectangle into a less regular rectangle. But would the rectangle have any curves in it or would it stay 'flat'?

For example could you always represent an observer's transformation as parabola or can it get more complex than that (for a 1d space, 1d time example)? When I look at the lorentz transformation formula (with a very untrained eye):

78195e8f63116bf11b2bbef574fbcc25.png


It seems simple enough that it wouldn't 'warp' the time slice in a very complex way. I just wonder what the limit of that warping is.
 
  • #4
You're right, the warping is really not that complex. It's linear, in fact.
 
  • #5
It is the same space and the same metric, just different basis vectors for different observers.
 

1. What are Lorentz transformations and how do they relate to time slices?

Lorentz transformations are a set of equations that describe how space and time coordinates change when transitioning between different inertial frames of reference. They are essential in understanding the effects of relativity, as they allow us to calculate how measurements of time and space change when observed from different perspectives. Time slices, also known as simultaneity slices, are imaginary planes of constant time used to visualize and analyze events in space-time.

2. Why are Lorentz transformations important in physics?

Lorentz transformations are important because they reconcile the principles of Galilean relativity and the constancy of the speed of light. They are a fundamental part of Einstein's theory of special relativity and are used to explain phenomena such as time dilation and length contraction. They also play a crucial role in modern theories of gravity and electromagnetism.

3. How do Lorentz transformations affect our perception of time?

Lorentz transformations have a significant impact on our perception of time. According to special relativity, time is not absolute but is relative to the observer's frame of reference. This means that time can appear to pass at different rates for different observers, depending on their relative velocities. This effect is known as time dilation and is a consequence of Lorentz transformations.

4. Can you explain the concept of time slices in more detail?

Time slices, also known as simultaneity slices, are imaginary planes of constant time that are used to visualize and analyze events in space-time. They allow us to break down the complex four-dimensional structure of space-time into a series of two-dimensional slices, making it easier to understand and analyze. Each time slice represents a specific moment in time, and events that occur within the same time slice are considered simultaneous from a specific observer's perspective.

5. How are Lorentz transformations related to the concept of space-time?

Lorentz transformations are closely related to the concept of space-time, which refers to the four-dimensional structure that combines space and time in special relativity. They describe how measurements of time and space change when observed from different frames of reference, and play a crucial role in how we understand the geometry of space-time. Without Lorentz transformations, it would not be possible to reconcile the principles of relativity with the observed constancy of the speed of light.

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