Is this universe endless?
2015-07-27 5:24 pm
Imagine you are in a spacecraft bound for a journey in space with no intention of returning or turning back, will there ever come an end?
回答 (21)
2015-07-27 5:46 pm
We don't know and how could we? We can only observe the universe between two horizons: the past one and the future one. The past one is that of the galaxies recessing from us faster than the speed of light and the future one is that of the galaxies the light of which hasn't reached us yet.
Then there is the geometry. You can't use Euclidean geometry at the scale of the universe. First of all ... what is a "straight line" at that scale? The path of inertia from something in motion? The path of the light? we already know that both are affected by gravity.
As such, there is no center nor edge to the universe.We can only observe it as if we were always at its center and that is why the Cosmic Microwave Background (CMB) the left-over of the big bang is coming from all directions in space. The big bang, the "center" of the universe is, actually, seen as a sphere around us. Amazing, isn't it?
Then there is the geometry. You can't use Euclidean geometry at the scale of the universe. First of all ... what is a "straight line" at that scale? The path of inertia from something in motion? The path of the light? we already know that both are affected by gravity.
As such, there is no center nor edge to the universe.We can only observe it as if we were always at its center and that is why the Cosmic Microwave Background (CMB) the left-over of the big bang is coming from all directions in space. The big bang, the "center" of the universe is, actually, seen as a sphere around us. Amazing, isn't it?
2015-07-27 8:36 pm
"Is this universe endless?"
For all practical purposes, yes.
We expect it is finite and unbounded, and our Rindler horizon (the edge where the contents of the Universe *there* is departing at exactly c) is inside the displayed Universe. So we could never return to *here* for any future now, unless we turned around and came back.
"Imagine you are in a spacecraft bound for a journey in space with no intention of returning or turning back, will there ever come an end?"
If you don't go very fast, the end will come in 125 billion years or so, just like for the rest of the contents of the Universe. If you move faster, it will seem like less than that to you when it ends.
But the end is in *time*, not in space.
For all practical purposes, yes.
We expect it is finite and unbounded, and our Rindler horizon (the edge where the contents of the Universe *there* is departing at exactly c) is inside the displayed Universe. So we could never return to *here* for any future now, unless we turned around and came back.
"Imagine you are in a spacecraft bound for a journey in space with no intention of returning or turning back, will there ever come an end?"
If you don't go very fast, the end will come in 125 billion years or so, just like for the rest of the contents of the Universe. If you move faster, it will seem like less than that to you when it ends.
But the end is in *time*, not in space.
2015-07-27 6:23 pm
yes universe endless because there is no any specific edge or boundary according present knowledge
2015-07-27 5:29 pm
No. A spaceship traveling in a straight line would eventually end up where it started, space is curved and non infinite. For more information I recommend reading "A universe from nothing" by Lawrence Krauss or watching one of his talks that went with the book (You can find them on youtube)
http://www.amazon.co.uk/Universe-Nothing-Lawrence-M-Krauss/dp/1471112683
In the book and talk he explains how we know the universe must be finite and the possible shapes that the universe could be in.
http://www.amazon.co.uk/Universe-Nothing-Lawrence-M-Krauss/dp/1471112683
In the book and talk he explains how we know the universe must be finite and the possible shapes that the universe could be in.
2015-08-05 7:48 pm
Space-time is finite but unbounded, it has no more of an end than the surface of the Earth. So far as the universe goes, that is a long and complicated matter, it may be infinite.
2015-07-29 4:12 am
GOOD QUESTION INFACT MANKIND HAS BEEN TO THE DEWELLING PLACE OF THE GODS A VERY LONG TIME FROM DIFFERENT PARTS OF THE EARTH. WHICH REFLECTS ITSELF IN ANCIENT WRITINGS, DRAWINGS AND UPON TABLETS. THESE DEPICTIONS WERE INSCRIBED TO PRESERVE THE KNOWING AS THEIR WOULD COME A TIME WHERE THESE WOULD SEEM FAIRY TALE AND PERHAPS UNREALISTIC. HUMAN FLESH & BONE HAS WALKED AMONG THE GODS AND THE LAST MOST RECENT PLACE OF THE FINAL INSCRIPTION OF THIS WAS HIDDEN AND PROTECTED IN A SET OF BOOKS THAT WERE BURN UP BY GREAT BRITTAN KNOWN TODAY AS THE LAST SERVIVING BOOK CALLED THE VOYNICH MANUSCRIPT. I ALONE HAVE DECODED VOYNICH AND I ALONE WAS PERMEATED WITH THE DETAILED WORKING KNOWLEGDE OF THE ORIGINAL COMPLETED SET. I KNOW WHO WROTE THE BOOKS AND WHAT ITS ORIGINAL PURPOSE WAS. I KNOW ALL THE SECRETS CONTAINED AS I HAVE CREATED AND SEALED THE FINAL BOOKS OF 20. A MASTEREPIECE OF MY MOST PRIZED
POSSESSION #FOREVERGREEN . P.S. THE ANSWERE TO YOUR QUESTION MY FRIND IS YES }:-)
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POSSESSION #FOREVERGREEN . P.S. THE ANSWERE TO YOUR QUESTION MY FRIND IS YES }:-)
FOLLOW ME ON TWITTER @BLACKBUNIE
參考: SAN LEANDRO CALIFORNIA
2015-07-29 1:09 am
To the point where we will never reach an actual "end" ... yes, the Universe is endless.
2015-07-28 8:56 pm
yes
2015-07-28 7:04 pm
Probably. Either endless or infinitely big.
2015-07-28 3:51 pm
At the limit it fades to zero.
2015-07-28 10:44 am
We'll get closer to knowing the answer with the James Webb Space Telescope in 2018.
2015-07-27 10:02 pm
Boundless
2015-07-27 8:49 pm
according to mainstream cosmology, it is endless.
though in that case, it's probably just more of the same: clusters of galaxies surrounding huge empty voids, the pattern repeating with no end.
if we are the only life in the Universe, you can give away a million galaxies to each inhabitant of Earth as a present, and there's still an infinite number of galaxies to give away.
What could you do with a million galaxies of your own?
what about a billion galaxies of your own?
though in that case, it's probably just more of the same: clusters of galaxies surrounding huge empty voids, the pattern repeating with no end.
if we are the only life in the Universe, you can give away a million galaxies to each inhabitant of Earth as a present, and there's still an infinite number of galaxies to give away.
What could you do with a million galaxies of your own?
what about a billion galaxies of your own?
2015-07-27 8:35 pm
For one thing, space itself is expanding. The rate of expansion is locally very small, but it adds up over long distances. For example, our Observable Universe appears to end only 13.8 billion light-years away because the amount of space between us and any point at that distance, is growing by a rate equal to the speed of light.
Therefore, even if your spaceship could go at the speed of light, you would never even reach these points (the one you aim for would forever be 13.8 billion light-years away, simply because every second, 300,000 km of new space would come into existence between you and your goal.
And we know that the whole universe is AT LEAST three times that. It could be infinite, it could be a thousand times, it could be six time, but it cannot be less than three times 13.8 billion light-years.
Therefore, you will never reach an edge. You will never go "all the way around" and come back the other way.
The other problem is that the rate of expansion appears to be increasing, so that even the point located 13.8 billion years away might end up being even further away from you, even after billions of years of traveling.
Therefore, even if your spaceship could go at the speed of light, you would never even reach these points (the one you aim for would forever be 13.8 billion light-years away, simply because every second, 300,000 km of new space would come into existence between you and your goal.
And we know that the whole universe is AT LEAST three times that. It could be infinite, it could be a thousand times, it could be six time, but it cannot be less than three times 13.8 billion light-years.
Therefore, you will never reach an edge. You will never go "all the way around" and come back the other way.
The other problem is that the rate of expansion appears to be increasing, so that even the point located 13.8 billion years away might end up being even further away from you, even after billions of years of traveling.
2015-07-27 8:00 pm
Space is curved in a higher dimension, go forward fast enough and you return to your start point from a different direction.
2015-07-27 6:14 pm
yeah!
2015-07-27 5:44 pm
The end will come for you in less than 150 years, as measured by your wristwatch. To everyone else, you'll appear to age extremely slowly for several billion years. But, long before you can traverse the universe and return to the general area of your starting point, you'll be dead.
2015-07-27 5:28 pm
The universe is finite. If you set off in a particular direction and could travel faster than the universe is expanding, eventually you'd finish up where you started.
2015-07-27 5:30 pm
There is no edge of the universe. The universe, by definition, is everything. It isn't growing into something. The universe is expanding itself into itself.
2015-07-27 5:27 pm
Yes, because there is no end and no "edge" of the universe. Thats because if there was, there would have to be something on the other side of that end or edge, and there is nothing that exists outside of the universe.
2015-07-27 5:37 pm
The UNIVERSE is NOT endless, so far as we know. it IS FINITE, an has an "end" or "edge" somewhere.
The SPACE that the universe exists is IS endless, or infinite.
The SPACE that the universe exists is IS endless, or infinite.
收錄日期: 2021-04-21 12:02:04
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