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It’s a common misunderstanding of the Big Bang. There is not a point where the universe originated. Rather everything was just closer together. Imagine traveli

It’s a common misunderstanding of the Big Bang. There is not a point where the universe originated. Rather everything was just closer together. Imagine traveling back in time - you would see galaxies move closer and closer - until everything was super dense and hot - like the center of the sun but everywhere.

saagarjha 8y ago
Isn’t the natural extension of things being “closer together” that they were at a singularity at some point (the Big Bang)?
- rough-sea 8y ago
  Nope. The universe is infinite, according to the model. We see observe galaxies speeding away from us in every direction - and it seems unlikely that the earth was the exact center of the Big Bang.
  - Qwertystop 8y ago
    Wouldn't that also be consistent with a finite universe as long as the distribution of galaxies is not biased towards or away from the edge, as long as the edge itself is beyond the observable part of the universe? We wouldn't have to be in the exact center, just not too close to the boundary.
    - cthalupa 8y ago
      >Wouldn't that also be consistent with a finite universe It would. It is not an unanimous conclusion that "stuff" is found everywhere in the universe and that the universe is infinitely big. However, that doesn't necessarily imply a center or an edge. The universe might be infinite and unbounded. The universe might be finite and bounded. The universe might be finite and unbounded. If the universe is finite and unbounded, we can go back to the ants on a balloon analogy. As expansion continues (and indeed speeds up) the balloon will continue to inflate, for forever. It is not possible to ever make the trip around the balloon to get back to your starting destination due to the expansion of the universe. The universe and spacetime are the 'surface' of the balloon - there is nothing inside of it, the center is not the middle of the balloon, and you cannot tunnel from one side of the balloon through to another. That isn't to say the observable universe is likely to be the extent or even close to the extent of the actual universe - it is likely still just the tiniest of fractions of the actual universe. We're probably finite and unbounded, and expanding into nothing. As the universe expands, it creates space where it did not exist. There's other theories that are reasonable, however. Some posit that our universe is a bubble in a true vacuum, and that there could be other bubbles containing other universes. Those theories are largely driven by the theory of inflation, which is the most accepted explanation as to how the universe expanded so far and so quickly in its early stages. (That's not to imply that the bubble multiverse theory is the most accepted explanation, though - just that most theories relating to bubble multiverses stem from looking at vacuum energy) We probably won't know for certain in our lifetimes. Intelligent lifeforms might never know for certain.
  - mordero 8y ago
    | and it seems unlikely that the earth was the exact center of the Big Bang. Wouldn't it be more accurate to say that everything was at the exact center of the Big Bang? Assuming it started from a singularity (which can't really be known), everything was in the center.
  - 6nf 8y ago
    We see stuff in all directions because the stuff extends much further than what we can observe. There may well be a 'middle' of the universe but there's no way to tell how close we are to it (or if it even exists at all.)
  - mcguire 8y ago
    But...if it is infinite in extent and (nearly) uniformly dense, how would the density decrease to the current value?

saagarjha 8y ago

Isn’t the natural extension of things being “closer together” that they were at a singularity at some point (the Big Bang)?

rough-sea 8y ago
Nope. The universe is infinite, according to the model. We see observe galaxies speeding away from us in every direction - and it seems unlikely that the earth was the exact center of the Big Bang.
- Qwertystop 8y ago
  Wouldn't that also be consistent with a finite universe as long as the distribution of galaxies is not biased towards or away from the edge, as long as the edge itself is beyond the observable part of the universe? We wouldn't have to be in the exact center, just not too close to the boundary.
  - cthalupa 8y ago
    >Wouldn't that also be consistent with a finite universe It would. It is not an unanimous conclusion that "stuff" is found everywhere in the universe and that the universe is infinitely big. However, that doesn't necessarily imply a center or an edge. The universe might be infinite and unbounded. The universe might be finite and bounded. The universe might be finite and unbounded. If the universe is finite and unbounded, we can go back to the ants on a balloon analogy. As expansion continues (and indeed speeds up) the balloon will continue to inflate, for forever. It is not possible to ever make the trip around the balloon to get back to your starting destination due to the expansion of the universe. The universe and spacetime are the 'surface' of the balloon - there is nothing inside of it, the center is not the middle of the balloon, and you cannot tunnel from one side of the balloon through to another. That isn't to say the observable universe is likely to be the extent or even close to the extent of the actual universe - it is likely still just the tiniest of fractions of the actual universe. We're probably finite and unbounded, and expanding into nothing. As the universe expands, it creates space where it did not exist. There's other theories that are reasonable, however. Some posit that our universe is a bubble in a true vacuum, and that there could be other bubbles containing other universes. Those theories are largely driven by the theory of inflation, which is the most accepted explanation as to how the universe expanded so far and so quickly in its early stages. (That's not to imply that the bubble multiverse theory is the most accepted explanation, though - just that most theories relating to bubble multiverses stem from looking at vacuum energy) We probably won't know for certain in our lifetimes. Intelligent lifeforms might never know for certain.
- mordero 8y ago
  | and it seems unlikely that the earth was the exact center of the Big Bang. Wouldn't it be more accurate to say that everything was at the exact center of the Big Bang? Assuming it started from a singularity (which can't really be known), everything was in the center.
- 6nf 8y ago
  We see stuff in all directions because the stuff extends much further than what we can observe. There may well be a 'middle' of the universe but there's no way to tell how close we are to it (or if it even exists at all.)
- mcguire 8y ago
  But...if it is infinite in extent and (nearly) uniformly dense, how would the density decrease to the current value?