Questions about Einstein and the Block Universe

In summary, the conversation discusses the concept of the block universe model and its implications on the possibility of alien contact in the past. While it is theoretically possible for aliens to send a signal to Earth in 1980, it would have had to be sent before 1980 according to the model's rules of space-time. However, there are also other issues to consider in terms of time and space measurements.
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Quantum Alchemy
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I find this subject fascinating. Einstein said the distinctions between past, present and future is just a persistent illusion. I was watching a special with Brian Greene and other Physicist who think we do live in a Block Universe and they explained it very well. Here's my question.

Say there was a hypothetical alien race at point x which would be at a distance where any signal they sent us today(present) would reach us in 1980. They would get information about our atmosphere and what music we listen to but from 1980 just like when we observe planets from Earth we're seeing them as they were in the past.

My question is, could they send a signal to us in 1980 today and would that mean 1980 is a point in space-time that still exists and a new worldine would occur different than ours where we made alien contact in 1980 or if there was a signal sent we would have heard it in 1980 but how would that work in the context of the block Universe?
 
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  • #2
We do not allow threads and questions about the block universe model, for the reasons described here so this thread is closed. More focused questions are of course welcome - you won't find a bunch of people more committed to exlaining relativity anywhere else on the internet.

My question is, could they send a signal to us in 1980 today and would that mean 1980 is a point in space-time that still exists and a new worldine would occur different than ours where we made alien contact in 1980 or if there was a signal sent we would have heard it in 1980 but how would that work in the context of the block Universe?
The quick answer is "no". To get a signal to us in 1980 they would have had to send it before 1980 (if they are X lightyears away and the signal travels at the speed of light, then at time 1980-X) and of course they can't discover anything about us in 1980 until after 1980+X when light from Earth in 1980 has reached them).

But please be aware that I have glossed over some serious problems around how we and the aliens could be using the same calendar even though we're in very different places. To form an accurate picture you'll want to understand the relativity of simultaneity and the notion of spacelike and timelike intervals; we can recommend some good starting points.
 

FAQ: Questions about Einstein and the Block Universe

1. Who is Einstein and what is the Block Universe?

Einstein was a renowned physicist who developed the theory of general relativity, which revolutionized our understanding of gravity. The Block Universe, also known as the "block time" or "eternalism," is a concept in physics that suggests that the past, present, and future all exist simultaneously in a four-dimensional block of spacetime.

2. What evidence supports the concept of the Block Universe?

There are several pieces of evidence that support the Block Universe theory. One is the observed phenomenon of time dilation, where time appears to pass at different rates for objects moving at different speeds. This is consistent with the idea that time is relative and that all moments in time exist simultaneously. Additionally, the equations of general relativity only work if time is treated as a dimension on par with the three dimensions of space, supporting the idea of a block of spacetime.

3. How does the Block Universe theory relate to determinism?

The Block Universe theory is often associated with determinism, the belief that all events are predetermined by previous events and the laws of nature. This is because if all moments in time exist simultaneously, then the future is already determined by the past and present. However, some physicists argue that quantum mechanics, which introduces randomness into the universe, may challenge this deterministic view.

4. Is the Block Universe theory widely accepted in the scientific community?

The Block Universe theory is a topic of ongoing debate and is not universally accepted in the scientific community. While many physicists, including Einstein, have supported the idea, others argue that it conflicts with our subjective experience of time and the concept of free will. Some also argue that the theory is not testable, making it more of a philosophical concept than a scientific one.

5. How does the Block Universe theory impact our understanding of the universe?

The Block Universe theory challenges our traditional understanding of time as a linear progression and suggests that the past, present, and future all exist simultaneously. This has implications for our understanding of causality and the nature of reality. It also raises philosophical questions about the concept of free will and the role of human agency in a predetermined universe.

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