Can Time Travel Take Us Back to the Big Bang?

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Discussion Overview

The discussion revolves around the concept of time travel, particularly in relation to the Big Bang. Participants explore theoretical implications of time travel to the past, the nature of time and space, and the fundamental principles of physics that govern these concepts.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question how one could travel to the past if time began at the Big Bang, suggesting that it raises paradoxical implications.
  • There is uncertainty about the existence of a destination prior to the Big Bang, with some asserting that there is no evidence for anything existing before it.
  • Participants discuss the constancy of the speed of light, with some suggesting that it is a fundamental aspect of physics that cannot be easily justified beyond its predictive power.
  • One participant argues that the universe does not need to expand into anything, referencing the Friedmann-Robertson-Walker solution to Einstein's equations as a model that describes the universe's expansion without external reference.
  • Concerns are raised about the meaningfulness of questions regarding causality and existence before the Big Bang, with some suggesting that current knowledge may not suffice to address these inquiries.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the nature of time, the Big Bang, and the implications of time travel. There is no consensus on these topics, and the discussion remains unresolved.

Contextual Notes

Limitations include the lack of evidence for pre-Big Bang existence, the challenge of defining meaningful questions about causality, and the dependence on theoretical models that may not fully capture the complexities of the universe.

Aashish sarode
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1.if we assume BIG BANG as frame of reference for time then how could one go to past ?
2.if i travel the time and go to past at the time of BIG BANG, at what place i will be?
3.why the speed of light is same for everything(moving or stationary)?
3.and what will be the apparent speed of light beam for another beam of light or particle moving at speed of light?
 
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1. We have no evidence that it is possible to travel in time. Also, it doesn't make sense to refer to the big bang as a frame of reference.

2. We have no evidence of the existence of anything before the big bang. So even if you could travel in time it's not clear that there is such a destination.

3. It just is. We only justify it by saying we can predict stuff perfectly if we assume that, and we get all sorts of problems if we don't

3 (again) There is no such perspective. It is self-contradictory to attempt to describe it because light would have to be stationary and moving at 3x108m/s at the same time.
 
Last edited:
Aashish sarode said:
1.if we assume BIG BANG as frame of reference for time then how could one go to past ?

Time, as we understand it, began at the big bang. So you're asking what would something that doesn't exist be like if it did exist. There's no way to answer that.

2.if i travel the time and go to past at the time of BIG BANG, at what place i will be?

If you're wondering where the big bang occurred, the answer is right where you are now. And right where everything is now. The universe didn't expand into an already existing space. Space itself expanded. And continues to do so.

3.why the speed of light is same for everything(moving or stationary)?

It's difficult to answer "why" questions because every answer is just met with another "why". One way to look at it is like this. The laws of physics, as they exist now, are stated in such a way that a state of rest is equivalent to a state of uniform motion. With no way to distinguish experimentally between those two states, the speed of light has to be the same to all observers. Thus the laws of physics treat those two states as being equivalent.

Experiments overwhelmingly confirm that these laws of physics work.

3.and what will be the apparent speed of light beam for another beam of light or particle moving at speed of light?

The laws of physics that I mentioned above put a strict upper limit on the speed of an observer. Observers cannot reach the speed of light. So again, you're asking what would something that doesn't exist be like if it did exist. You might find an answer to such questions somewhere, but not within the body of knowledge known as physics.
 
If something didnt exist before big bang then in which thing the universe is expanding and which things made big bang to happen? Also according to Mister T there was nothing before big bang so what made energy to convert into mass?
 
The universe doesn't need to be expanding into anything. You can write a complete description of a 4d object where each 3d "slice" is bigger than the one on one side of it and smaller than the one on the other side without referencing anything outside - it's called the Friedmann-Robertson-Walker (FRW - sometimes Lemaitre gets a look in and you see FLRW) solution to Einstein's equations.

It isn't clear that anything caused the big bang - our notions of causality are all based on our experience inside the universe. There's no particular reason why they should apply outside the universe, even assuming that there's anywhere outside the universe to talk about.

Essentially, it isn't clear that your questions are meaningful. And even if they are, we don't yet have the knowledge to answer them.
 
Last edited:
Ibix said:
Essentially, it isn't clear that your questions are meaningful. And even if they are, we don't yet have the knowledge to answer them.

And on that note, this thread is closed.
 
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