The spatial universe is believed to have one of three possible geometriesIbix said:
No. All FLRW solutions, including the flat and open ones, are spatially homogeneous. There is matter everywhere and always was.Bosko said:
Wrong. The matter density in the universe is the same everywhere, even in spatially infinite universes.Bosko said:
No, it doesn't. A uniform infinite expanse has no center.Bosko said:
No, it isn't. A moment in time is not a center of anything.Bosko said:
Now that this has been answered, the real mind blowing question you will find is how the observable universe can be 93 billion ly across when the universe is less than 14 billion years old.Thecla said:
Then the amount of matter is infinite.PeterDonis said:
Why would it be contradictory? It is very consistent with the assumptions of homogeneity and isotropy.Bosko said:
A flat and open universe has infinite volume, if I'm not mistaken.Orodruin said:
Yes.Bosko said:
It's a valid solution of the relevant equations. What more do you want?Bosko said:
Nature doesn't care what does or does not seem contradictory to you.Bosko said:
It does.Bosko said:
It is, as has already been said.Bosko said:
The universe does not feel compelled to arrange itself to your liking, I'm afraid.Bosko said:
You can't travel infinitely fast, but if we rephrase your question as, will observers in all the other galaxies, at the same elapsed time by their clocks from the Big Bang, say that their own observable universe is 93 billion light years wide, the answer is yes.Thecla said:
The diameter of the observable universe is approximately 93 billion light-years. This measurement represents the distance that light has traveled since the Big Bang, taking into account the expansion of the universe.
The diameter of the observable universe is estimated using various astronomical observations, including the cosmic microwave background radiation, redshift of distant galaxies, and the distribution of galaxies. These methods help scientists determine how far light has traveled and the rate of expansion of the universe.
The observable universe is limited by the speed of light and the age of the universe. Since light takes time to travel, we can only see objects whose light has had enough time to reach us since the Big Bang. The entire universe may be much larger, and possibly infinite, beyond what we can observe.
The observable universe does not have a physical boundary in the traditional sense. Instead, it is defined by the limit of how far we can see, based on the distance light has traveled since the beginning of the universe. Beyond this limit, there may be more universe that we cannot observe.
The expansion of the universe affects the diameter of the observable universe because as the universe expands, the distance between galaxies increases. This means that while the observable universe has a fixed diameter based on the light that has reached us, the actual universe continues to grow, potentially expanding the observable limits over time as new light reaches us.