Time from the origin of universe

In summary: The "size" of the universe is difficult to define and measure, especially when the universe is not homogeneous and isotropic on large scales. This leads to various definitions of size, like the horizon size, the observable universe size, the particle horizon size, the event horizon size, etc. In summary, the conversation touches on the topics of the constancy of spacetime throughout the universe, the possibility of spacetime breaking down in certain regions, the age of the universe at different points in space, the concept of dark energy and its potential source, the possibility of time dilation under special relativity, and the size of the universe at different points in time. It also mentions the ideas of singularities and the work of
  • #1
emc2cracker
91
0
I have a question for the bright minds here. I have often wondered if spacetime has been constant thoughout the universe or if there are places where spacetime breaks down. One of these points I often imagine about is the very origin point of the Big Bang. Does anyone know of any papers addressing this question or have any input?

Basically I am wondering if the age of the universe would be the same at all points in space, in particular from the very origin of the inflation. In my imagination this point seems a likely spot for the source of dark energy, and I often wonder if I could build a spaceship and fly to one of these points of inflation or dark energy would time exist there as we know it?
 
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  • #2
Big Bang is not a point, it is EVERYWHERE. If Universe is infinite now, then it was infinite from the very beginning, and Big Bang was also infinite.

The age of the Universe (13.7 b y) is maximum proper time - for all objects at rest to CMB - this is true for all objects we see. However, for, say, very high speed particle the proper time from the Big Bang can be much shorter.
 
  • #3
Yes I know everything was in that little space and there was no outside... but wouldn't there be a point in space today where the inflation started from?

And as far as you know the only time dilation possible is under special relativity? Spacetime is consistent for all objects at rest no matter where they are? I would think if there are literally holes in spacetime inside of black holes then there time would not exist at all at least?

Maybe someone can dumb this down for me on the infinite from the beginning part its hard to imagine that even for me lol. I was under the impression that the universe 1 trillionth of a second after the big bang would have been the size of a softball? Are there two different models I am thinking of here?

Thank you very much dmitry and everyone, I don't know what I would do to satisfy my curiosity without this place!
 
  • #4
emc2cracker said:
1 but wouldn't there be a point in space today where the inflation started from?

2 And as far as you know the only time dilation possible is under special relativity?

3 Spacetime is consistent for all objects at rest no matter where they are?

4 I would think if there are literally holes in spacetime inside of black holes then there time would not exist at all at least?

5 I was under the impression that the universe 1 trillionth of a second after the big bang would have been the size of a softball?

1 no, all points are equal.
2 'only'? what do you mean? SR is a particular case of GR, so there is time dilation in GR as well
3 Spacetime is consistent for all objects - at rest and not at rest. They all agree on if some event happened or not - they just don't agree on when and where.
4 No. Except for singularities (and future theory will definitely get rid of them) everyhting is smooth, even inside the black holes
5 This is about the radius of VISIBLE universe.
 
  • #5
I agree, thanks that makes perfect sense. If anyone has anything to add I'm all ears and taking notes :)

So Gerald Schroeder is just a quack, I thought so I didn't find one published paper on that guy.
 
  • #6
If I could add a little...

1. Perhaps. In the early universe just after the big bang, the energy density of the universe could have taken on different values at different points in space. The inflaton is typically believed to have had chaotic initial conditions, so that in many places in the universe the conditions weren't right for inflation. However, in some patch of spacetime, the conditions were just right (spacetime was sufficiently smooth and the inflaton field dominated the local energy density). This patch inflated and became our entire observable universe (and probably then some). So, in a sense, inflation did occur in perhaps a small region of spacetime (not a point, though).

2. Gravitational time dilation is unique to general relativity and is very important cosmologically. Time is dilated for observers in gravitational potential wells relative to those in free space.

4. There's little use in talking about singularities. No physicists believes them to be physical. It is instead believed that quantum gravity becomes relevant before such a singularity forms physically.
 

1. What is the origin of the universe?

The origin of the universe is the moment in time when all matter, energy, space, and time came into existence. It is believed to have occurred approximately 13.8 billion years ago in an event known as the Big Bang.

2. How do scientists measure the age of the universe?

Scientists use a variety of methods to measure the age of the universe, including studying the cosmic microwave background radiation, the expansion rate of the universe, and the ages of the oldest known stars and galaxies.

3. How did the universe evolve from its origin?

After the Big Bang, the universe underwent a period of rapid expansion known as inflation. As it expanded, matter and energy began to clump together to form stars, galaxies, and larger structures. Over billions of years, these structures continued to evolve and shape the universe as we know it.

4. Is time the same throughout the universe?

According to Einstein's theory of relativity, time is relative and can vary depending on one's frame of reference. This means that time can appear to pass at different rates for different observers, but the laws of physics still hold true regardless of one's perception of time.

5. Will the universe ever end?

There are several theories about the ultimate fate of the universe, but it is currently believed that the expansion of the universe will continue indefinitely, leading to a state of heat death where all matter and energy are evenly distributed and no longer able to sustain life or change. However, this is still a topic of ongoing research and debate among scientists.

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