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"How universe works" said size of universe about 150 billion light years across. However, universe said to be about 13.5 billion years old?
Which would mean something goes faster than light (well Krauss said "nothing" can, and special meaning to his nothing). Couple of ideas want to bounce: does this mean perhaps that most of expansion (about 123 billion light years) occurred before uni "settled down" with laws of physics, so could be galaxies and all out there?
If not, then reasonable to assume the "visible universe" occupies about 27 billion light years across part of space, so beyond that it is really really empty (as opposed to our "mostly empty", save dark energy & matter, part of universe.
6 Answers
- Mark GLv 75 years ago
Firstly we have no idea how big the Universe is only the Observable Universe, and that is about 90 billion light years across. The reason for your question is that you haven't taken into account how long it takes light to reach an observer. The most distant galaxies in the Observable Universe formed about 13.5 billion years ago, galaxies that young are observed when they were 3.5 billion light years away, it has taken 3.5 billion years for the light to get to use but in the mean time space has expanded so the galaxies are now at about 45 billion light years!!
- QuadrillianLv 75 years ago
The universe has been expanding for fourteen billion years. What you and the vast majority of people fail to realise is that every unit volume of space is expanding, not just the outer edge. It is space that is expanding, not the outer boundary of the universe. Since it is every volume of space that is expanding, the expansion is cumulative the further out you go. That is exactly why at some point in the far distance anything embedded in space appears to recede at close to light speed. The object itself is not necessarily moving, but every bit of space between here and there expands at a tiny rate but the cumulative effect is to drive off the object at close to light speed.
Hence distant objects are indeed much further out than fourteen billion light years.
Cheers!
- Brigalow BlokeLv 75 years ago
Nothing with mass may exceed the velocity of light. Space does not have mass and therefore has no such restrictions. According to some, well within the first second the Universe was already far larger than this galaxy.
- Anonymous5 years ago
Thi is not a question. it's a rant.
Age and distance across something are not the same thing. a light year is a unit of DISTANCE, NOT TIME.
- ?Lv 75 years ago
You failed to read your text book.
Nothing may cross space faster than light - this makes no ruling about space expanding faster than light.
- Anonymous4 years ago
You are incapable of seeing, I would guess, how this sounds so much like the ravings of someone in delirium state.... I suggest you see a mental health practitioner as soon as possible BE CURSED.