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From a layman that enjoys scifi, I always thought universe appears to be infinite because we are in a lower dimension. Gravity is a product of interaction betwe

by zyang 3y ago

From a layman that enjoys scifi, I always thought universe appears to be infinite because we are in a lower dimension. Gravity is a product of interaction between parallel 3D universes. And dark matter is just matter from other universes. Is there any basis to this theory or am I over simplifying it.

fallingfrog 3y ago
That’s a bit too vague to really say whether there’s anything to it. I think you would want to study physics and try to make your ideas more precise.
ulizzle 3y ago
The universe is expanding not infinite. The weird part is the question is expanding into what or where. There’s not actually any proof for multiverses, that’s a hypothetical, related to the whole sims theory. Not saying that could not be true but there’s more proof that this isn’t the first or the last universe than there are other universes.
- atq2119 3y ago
  > The weird part is the question is expanding into what or where. Why would there have to be an "into"? It seems like the most parsimonious expansion is that there isn't one. My limited understanding of the math is also that that's what the math says.
  - ulizzle 3y ago
    That’s the whole controversy of the cosmological constant that this paper brings up. The math squares up in theory but observational data is way off. The universe being small and it’s expansion just a mirage is one attempt to square the data and theory. I’m not an expert so I don’t have any answers or anything. I just went into this rabbit hole recently when I got sick recently.
akomtu 3y ago
"lower dimension" in what sense?
eru 3y ago
> From a layman that enjoys scifi, I always thought universe appears to be infinite because we are in a lower dimension. The universe doesn't appear to be infinite. The observable universe has a very definite size. We can't really say much about what comes beyond. But the paper the linked article talks about tries. > Gravity is a product of interaction between parallel 3D universes. You might like https://en.wikipedia.org/wiki/Holographic_principle https://en.wikipedia.org/wiki/Holographic_principle > The holographic principle is a property of string theories and a supposed property of quantum gravity that states that the description of a volume of space can be thought of as encoded on a lower-dimensional boundary to the region — such as a light-like boundary like a gravitational horizon.[1][2] First proposed by Gerard 't Hooft, it was given a precise string theoretic interpretation by Leonard Susskind,[3] who combined his ideas with previous ones of 't Hooft and Charles Thorn.[3][4] Leonard Susskind said, “The three-dimensional world of ordinary experience––the universe filled with galaxies, stars, planets, houses, boulders, and people––is a hologram, an image of reality coded on a distant two-dimensional surface."[5] As pointed out by Raphael Bousso,[6] Thorn observed in 1978 that string theory admits a lower-dimensional description in which gravity emerges from it in what would now be called a holographic way. The prime example of holography is the AdS/CFT correspondence. So basically the opposite of what you are describing: gravity emerges because we are in a higher dimension. > And dark matter is just matter from other universes. Dark matter can be seen as the label we give to a bunch of experimental findings / problems. https://en.wikipedia.org/wiki/Dark_matter https://en.wikipedia.org/wiki/Dark_matter says: > [Dark matter's] existence is implied by various astrophysical observations which cannot be explained by general relativity unless more matter is present than can be seen. Evidence for dark matter comes from many different angles, such as galaxy dynamics and formation,[2] gravitational lensing,[3] and the cosmic microwave background, along with astronomical observations of the observable universe's current structure, the formation and evolution of galaxies, mass location during galactic collisions,[4] and the motion of galaxies within galaxy clusters. Positing matter that has gravity but doesn't otherwise interact (much) with the rest of the universe can explain those observations. But other observations are also possible. Eg some people like to fiddle with the laws of gravity to explain why the galaxies don't fly apart.
halgir 3y ago
> And dark matter is just matter from other universes. This is a fun idea. You can illustrate it by drawing your classic 2D universe on a piece of paper, sprinkle metal dust around, and move it with magnets held above or below the paper. To the 2D creature, matter in their universe seems to be affected by forces from entirely invisible objects, but 3D creatures can observe exactly what's happening. Likewise our "dark matter" would simply be matter on different planes in the same >3D universe as us. We neither see it nor collide with it, but we observe its gravitational pull.
- uh_uh 3y ago
  That matter from the other universes seem to pretty well line up with galaxies in our own universe which makes this theory a bit sus. I'd expect at least some of them to be scattered at random places, whose gravitational lensing effect we should be able to observe.
  - halgir 3y ago
    The matter is not in a different universe, but in our universe. Just a different spatial plane of it. Much like a 3D structure intersected by the plane of a 2D universe is surrounded "by itself" in the third spatial dimension. In such a case, the extradimensional matter lines up quite well with the observable. Mind you, I'm not a physicist, and I'm not (necessarily) proposing this as a serious model. Just an internet commenter riffing on a fun idea.
mejutoco 3y ago
From your description, I am guessing this intuition comes from Flatland, but in case other readers are interested https://www.goodreads.com/ne/book/show/433567.Flatland https://www.goodreads.com/ne/book/show/433567.Flatland

by zyang 3y ago

fallingfrog 3y ago

That’s a bit too vague to really say whether there’s anything to it. I think you would want to study physics and try to make your ideas more precise.

ulizzle 3y ago

The universe is expanding not infinite. The weird part is the question is expanding into what or where. There’s not actually any proof for multiverses, that’s a hypothetical, related to the whole sims theory. Not saying that could not be true but there’s more proof that this isn’t the first or the last universe than there are other universes.

atq2119 3y ago
> The weird part is the question is expanding into what or where. Why would there have to be an "into"? It seems like the most parsimonious expansion is that there isn't one. My limited understanding of the math is also that that's what the math says.
- ulizzle 3y ago
  That’s the whole controversy of the cosmological constant that this paper brings up. The math squares up in theory but observational data is way off. The universe being small and it’s expansion just a mirage is one attempt to square the data and theory. I’m not an expert so I don’t have any answers or anything. I just went into this rabbit hole recently when I got sick recently.

akomtu 3y ago

"lower dimension" in what sense?

eru 3y ago

> From a layman that enjoys scifi, I always thought universe appears to be infinite because we are in a lower dimension. The universe doesn't appear to be infinite. The observable universe has a very definite size. We can't really say much about what comes beyond. But the paper the linked article talks about tries. > Gravity is a product of interaction between parallel 3D universes. You might like https://en.wikipedia.org/wiki/Holographic_principle https://en.wikipedia.org/wiki/Holographic_principle > The holographic principle is a property of string theories and a supposed property of quantum gravity that states that the description of a volume of space can be thought of as encoded on a lower-dimensional boundary to the region — such as a light-like boundary like a gravitational horizon.[1][2] First proposed by Gerard 't Hooft, it was given a precise string theoretic interpretation by Leonard Susskind,[3] who combined his ideas with previous ones of 't Hooft and Charles Thorn.[3][4] Leonard Susskind said, “The three-dimensional world of ordinary experience––the universe filled with galaxies, stars, planets, houses, boulders, and people––is a hologram, an image of reality coded on a distant two-dimensional surface."[5] As pointed out by Raphael Bousso,[6] Thorn observed in 1978 that string theory admits a lower-dimensional description in which gravity emerges from it in what would now be called a holographic way. The prime example of holography is the AdS/CFT correspondence. So basically the opposite of what you are describing: gravity emerges because we are in a higher dimension. > And dark matter is just matter from other universes. Dark matter can be seen as the label we give to a bunch of experimental findings / problems. https://en.wikipedia.org/wiki/Dark_matter https://en.wikipedia.org/wiki/Dark_matter says: > [Dark matter's] existence is implied by various astrophysical observations which cannot be explained by general relativity unless more matter is present than can be seen. Evidence for dark matter comes from many different angles, such as galaxy dynamics and formation,[2] gravitational lensing,[3] and the cosmic microwave background, along with astronomical observations of the observable universe's current structure, the formation and evolution of galaxies, mass location during galactic collisions,[4] and the motion of galaxies within galaxy clusters. Positing matter that has gravity but doesn't otherwise interact (much) with the rest of the universe can explain those observations. But other observations are also possible. Eg some people like to fiddle with the laws of gravity to explain why the galaxies don't fly apart.

halgir 3y ago

> And dark matter is just matter from other universes. This is a fun idea. You can illustrate it by drawing your classic 2D universe on a piece of paper, sprinkle metal dust around, and move it with magnets held above or below the paper. To the 2D creature, matter in their universe seems to be affected by forces from entirely invisible objects, but 3D creatures can observe exactly what's happening. Likewise our "dark matter" would simply be matter on different planes in the same >3D universe as us. We neither see it nor collide with it, but we observe its gravitational pull.

uh_uh 3y ago
That matter from the other universes seem to pretty well line up with galaxies in our own universe which makes this theory a bit sus. I'd expect at least some of them to be scattered at random places, whose gravitational lensing effect we should be able to observe.
- halgir 3y ago
  The matter is not in a different universe, but in our universe. Just a different spatial plane of it. Much like a 3D structure intersected by the plane of a 2D universe is surrounded "by itself" in the third spatial dimension. In such a case, the extradimensional matter lines up quite well with the observable. Mind you, I'm not a physicist, and I'm not (necessarily) proposing this as a serious model. Just an internet commenter riffing on a fun idea.

mejutoco 3y ago

From your description, I am guessing this intuition comes from Flatland, but in case other readers are interested https://www.goodreads.com/ne/book/show/433567.Flatland https://www.goodreads.com/ne/book/show/433567.Flatland