Physics Guy wrote:. No-one can actually say anything about where the universe is in relation to anything outside itself, but Big Bang cosmology doesn't say anything about that, either, so you may as well say that the answer to Where is the universe? hasn't changed since the Big Bang.
A universe cannot be expanding without an outside. Our expanding universe has to be inside another universe. Right? Or am I full of it?
No, your conundrum simply accentuates the loose ends that theorists are willing to explain away - usually through condescension. The short answer about the Universe expanding is simply "yes, it is expanding - it is turtles all the way down"....the longer answer is that you are trying to answer a 4-dimensional question with a 3-dimensional answer.
Seek freedom and become captive of your desires...seek discipline and find your liberty I can tell if a person is judgmental just by looking at them what is chaos to the fly is normal to the spider - morticia addams If you're not upsetting idiots, you might be an idiot. - Ted Nugent
Human brains are only so good at visualizing geometry. They've evolved to deal with motion in three dimensions, but you don't have to cope with curvature in four dimensions to escape from tigers so human brains haven't gotten that far.
If we try to visualize something expanding, our brains insist that it has to be expanding into some other space. But that's really just a limitation of our neural hardware. It's not a fact of geometry.
Geometry can logically describe a curved space without referring to anything outside the space. We can do that fine in two dimensions. You can navigate the whole world in latitude and longitude and you never have to refer explicitly to a third dimension. The most you might have to do is remember that a degree of longitude represents a bigger distance at the equator than it does farther north or farther south. Or you might have to recognize that if you keep going as straight as you can on the surface of the Earth you will eventually come back to where you started, having gone round the world. If you want to reconcile those two weird facts with your brain's visualization hardware, you have to think in three dimensions, but if you just want to sail your ship, you can simply build those rules about straight travel and longitude into your two-dimensional geometry, and it will all work out fine.
General relativity takes a ship-sailing approach. It builds rules of curved space into four dimensions, and doesn't refer to any external fifth dimensional space into which the universe might be expanding. Is there such a space? Or is it only a false expectation of our primitive brains that makes us want to imagine such a space?
Physics doesn't know, and doesn't say anything about those questions either way.
Physics Guy wrote:You can navigate the whole world in latitude and longitude and you never have to refer explicitly to a third dimension.
Unless said exploration is by airplane (fixed wing or non-fixed wing).
Seek freedom and become captive of your desires...seek discipline and find your liberty I can tell if a person is judgmental just by looking at them what is chaos to the fly is normal to the spider - morticia addams If you're not upsetting idiots, you might be an idiot. - Ted Nugent
Physics Guy wrote: If we try to visualize something expanding, our brains insist that it has to be expanding into some other space. But that's really just a limitation of our neural hardware. It's not a fact of geometry.
I wonder if there are superior aliens out-there with a superior brain. Thanks for your thoughtful response Physics Guy. In a private message I did ask you about aliens and lasers. Hopefully you have the time to reply.
DoubtingThomas wrote:I wonder if there are superior aliens out-there with a superior brain.
or inferior aliens with inferior brains? either way that's still 3d thinking, amiright?
Seek freedom and become captive of your desires...seek discipline and find your liberty I can tell if a person is judgmental just by looking at them what is chaos to the fly is normal to the spider - morticia addams If you're not upsetting idiots, you might be an idiot. - Ted Nugent
Physics Guy wrote:. No-one can actually say anything about where the universe is in relation to anything outside itself, but Big Bang cosmology doesn't say anything about that, either, so you may as well say that the answer to Where is the universe? hasn't changed since the Big Bang.
A universe cannot be expanding without an outside. Our expanding universe has to be inside another universe. Right? Or am I full of it?
In a multiverse scheme this makes sense, but be careful, the Creationists will insist you are making stuff up in order to avoid a Creator, and it sorta like peeves em off kind of......
Dr CamNC4Me
"Dr. Peterson and his Callithumpian cabal of BYU idiots have been marginalized by their own inevitable irrelevancy defending a fraud."
PG General relativity takes a ship-sailing approach. It builds rules of curved space into four dimensions, and doesn't refer to any external fifth dimensional space into which the universe might be expanding. Is there such a space? Or is it only a false expectation of our primitive brains that makes us want to imagine such a space?
Brian Green in "The Hidden Reality" mentions a contemporary of good ole Einstein a guy named Kuluva(?) who demonstrated that if a 5th dimension were real, it would be able to mathematically unite gravity with the electromagnetic field! Einstein never threw the paper away, but by the 1930's everyone was quantum zapping their brains, so it didn't catch on. Then along came string theory, and wowsa! Now we gots 11 dimensions to fathom!
Dr CamNC4Me
"Dr. Peterson and his Callithumpian cabal of BYU idiots have been marginalized by their own inevitable irrelevancy defending a fraud."
Philo Sofee wrote: In a multiverse scheme this makes sense, but be careful, the Creationists will insist you are making stuff up in order to avoid a Creator, and it sorta like peeves em off kind of......
and that is another thing I don't fully understand, but I guess the answer depends on the model. Would other universes be outside our universe?
Last edited by Guest on Sat Mar 31, 2018 6:02 pm, edited 2 times in total.
DoubtingThomas wrote:I wonder if there are superior aliens out-there with a superior brain.
or inferior aliens with inferior brains? either way that's still 3d thinking, amiright?
It is very likely that inferior aliens with inferior brains exists in the universe. Perhaps some small colony of fish-like aliens live in Europa or something.
