Jaime Rudas's latest activity
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No, that's not correct. Knowing the spacetime curvature does not tell you the deformation, because spacetime curvature only tells you... -
If the paper were oriented radially, then yes, you would be able to draw a triangle on it whose angles would not add up to 180 degrees...
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It depends on how the paper is oriented and what its state of motion is. But for a piece of paper of ordinary size and a black hole of...
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Jaime Rudas reacted to PeterDonis's post in the thread I Euclidean geometry and gravity with
Informative.
That's correct. Note, though, that when you have a star in the center instead of a black hole, the spacetime geometry inside the star is... -
Jaime Rudas replied to the thread I Euclidean geometry and gravity.From this, I understand that for a sphere of area ##A## around a very massive and dense star, its radius ##R## will be greater than...
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That's not what I said. What I said is that, if you're observing from a distance objects that are at rest fairly close to a black hole's...
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Jaime Rudas replied to the thread B Matter density right after the decoupling.On the other hand, the margin of error in calculating the age of the universe is on the order of hundreds of millions of years, so what...
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Jaime Rudas replied to the thread B Matter density right after the decoupling.I consider the radius of the observable universe to be, by definition, the greatest distance that anything could reach during the age of...
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Jaime Rudas replied to the thread B Rutgers finds a transparent Einstein Cross - apparently a dark matter "halo"..I think you underestimate the enormous retrospective adaptability that these "theories" have always demonstrated.
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Jaime Rudas reacted to martinbn's post in the thread I What Are the Limits of the Universe According to Cosmologists? with
Like.
There is a theorem, i think Hilbert, that says that a constant negative curvature surface cannot be embedded isometrically in three... -
Jaime Rudas reacted to A.T.'s post in the thread I What Are the Limits of the Universe According to Cosmologists? with Informative.
See this answer: https://physics.stackexchange.com/a/43061
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Jaime Rudas replied to the thread I What Are the Limits of the Universe According to Cosmologists?.The Gaussian curvature ##K## of the hyperboloid ##x^2+y^2-z^2=1## is ##\frac {-1}{(1+2z^2)^2}##. Thus, when ##z=0##, the curvature...
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Jaime Rudas replied to the thread I What Are the Limits of the Universe According to Cosmologists?.The German Wikipedia says: Which, translated, would be: I understood that the hyperboloid didn't have constant Gaussian curvature. Am...
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Jaime Rudas replied to the thread I What Are the Limits of the Universe According to Cosmologists?.Yes, I think I was wrong. Although I don't know if it's possible to define curvature at the "edge" of the pseudosphere (i.e., at the...
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Jaime Rudas replied to the thread I What Are the Limits of the Universe According to Cosmologists?.Yes, maybe, but there is no such surface embedded in Euclidean three-dimensional space.