Questions regarding the 4-dimensional background structure of our universe.

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14
votes
4answers
1k views

Does matter accumulate just outside the event horizon of a black hole?

My understanding is that time slows and approaches stopping when approaching the event horizon of a black hole. I have seen this explained several places, including a brief explanation in the last ...
16
votes
2answers
1k views

Age of the universe and time dilation

Given our knowledge and the standard cosmological model, we estimate that the age of the universe is about 13.7 billion years old. How much sense does it make to talk about the age of the ...
2
votes
1answer
60 views

How could we tell if the Universe is infinite? [duplicate]

I've heard from a number of people that the Universe is infinite, and from my perspective, I can't see how this can actually be known, especially given that the Universe started out a finite size and ...
2
votes
2answers
125 views

Does all of time exist and if so where is it?

I've recently learned about the theory of relativity and time. I'm trying to understand it more. My (basic) understanding is that there is no distinction between past present and future and that ...
16
votes
5answers
3k views

By putting a mirror in space, would we be able to see into the past?

I only ask this because of how fast light travels. The question remains in the title. Why, or why not, would this work?
6
votes
3answers
501 views

What is a singularity? What is at the center of a black hole? Specifically regarding space-time

So because I can only really think of space-time in 2-dimensions like a sheet of something, my assumptions might be wrong to begin with. I was watching a YouTube video on black-holes and there was a ...
9
votes
2answers
613 views

Why is the observable Universe larger than its age would suggest?

The age of the Universe is estimated at 13.8 billion years, and current theory states nothing can exceed the speed of light, which can lead to the incorrect conclusion that the universe can't have a ...
8
votes
1answer
263 views

Time according to the gravity of Sagittarius A?

This may be a really dumb question (I'm more of a Biologist than an Astronomer) so I apologize in advance for my little knowledge pertaining to Astronomy, but, if I'm not mistaken, time is effected by ...
5
votes
1answer
123 views

What it would look like to observe people with a different time flows?

As I learned, that the bigger gravity source you are influenced by the more slow time ticks for you, the farther away you are from a gravity source the faster times ticks. So Imagine two different ...
4
votes
2answers
313 views

Why does time get slow near a black hole? [closed]

Why exactly does time get slow around a black hole? And does it provide a way to go into the future?
1
vote
2answers
76 views

Center of the universe

Big bang is not an explosion, but an expansion of space and time. Universe had almost infinite density... wait a moment. If it had ALMOST infinite density, it had a certain volume, and thus, space ...
1
vote
2answers
141 views

A camera and time dilation?

If I travelled near a black hole, my time would progress slower relative to someone on Earth. This is clear enough. However, what if we sent a probe with a camera to a black hole? When we watch the ...
1
vote
4answers
160 views

Does time slow down because the universe is expanding at an accelerating rate?

If the universe is expanding at an accelerating rate, such that the galaxies' moving away from each other is accelerated, then time should also slow down. And when universe will accelerate to the ...
1
vote
2answers
198 views

Why doesn't this paradox disprove (some) multiverse quantum gravitational theories?

As I understand it, one theory of the multiverse is that there are an infinite number of universes separated by small distances in other (than our observable 3/4) dimensions and that gravity is weak ...