Questions tagged [theories]
Questions regarding models proposed that can solve problems.
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Someone explain how a naked singularity is possible
I was reading this wiki article about naked singularities, however I don't really understand the how a gravitational singularity can simply exist without an event horizon. Can someone explain/...
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Is it theoretically possible for the Sun to go dark?
If photons potentially take millions/billions of years to find their way to the surface of the Sun from the core, bouncing off billions of other atoms on their way. Is it theoretically possible to ...
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Black hole explosion due to rotation [duplicate]
I am not an expert, I was just thinking about this scenario:
A black hole that, for some reason, will start spinning faster and faster. Is it theoretically possible that the rotation becomes so fast ...
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How can Kerr black holes have a 'speed limit' to how fast they can spin?
Obviously, the speed of light is a presumed limit, at least for 'physical' objects moving 'within' ('through'?) spacetime, but...
In recent news some scientists believe they have figured out the ...
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Why are WIMP dark matter particles, if Majorana-like, expected to annihilate upon contact? But not neutrinos?
I have heard a lot recently about so-called 'dark stars'; stars that are formed with the help of the gravitational pull of dark matter, or perhaps entirely from self-annihilating Majorana-type dark ...
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Is the Big Bang a theory or a model?
I ask this because someone mentioned ‘it isn't a theory, it's a model’ in the comments in an old question of mine: Is the expansion of the universe proof of the big bang?
I guess defining terms is ...
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Why do cosmologists assume that inflation began shortly after the Big Bang, rather than at the exact start?
Somehow, I have never come across an explanation of why cosmologists claim that the alleged inflation of the very early universe occurred not at the Big Bang, but very shortly afterwards (~10^-36 to ...
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Spacetimes where symmetries vary from place to place?
Are there spacetimes or metrics where symmetries (like Poincaré, Lorentz, diffeomorphism, translational... invariances) are only local and the symmetries of one local neighbourhood are not, a priori, ...
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Does gravity extend out infinitely?
The sun’s gravity gets weaker the further out you go, the same goes with the Earth. But even back out all the way to Neptune and Pluto, the gravity is still there. The sun can even keep Sedna which at ...
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What is the relation between size (radius) of an astronomical object and the speed of oscillation of 'light' coming from it? (Strength/amplitude)?
From the year-end issue of New Scientist Magazine (Dec. 18-31,2021):
Astronomy:
'Space Cow' explosion was probably a failed supernova'
Page 10: 'They found that the strength of this radiation ...
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Do Einstein's ten field equations use 20 or 40 variables? (2 or 4 for each tensor equation?)
One site I came across says Einstein's 10 Field Equations use 20 variables, while another said 40.
There are four variables in spacetime - three for space and one for time, right?
But there are two ...
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Does the Schwarzschild metric solution require two (A and B, or g11 and g44) or four components (g11, g22, g33 and g44)?
Different places on the web imply that Schwarzschild's metric uses four components or separate equations, similar to how Einstein's full set requires 6 or 10, or they say only two are needed. Is it 2 ...
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What does 's' or 'ds' or $ds^2$ mean in the Schwarzschild equation(s)? [closed]
And:
These are from Wikipedia on Schwarzschild metric, Derivation of the Schwarzschild metric and the last is from Science Direct, Schwarzschild metric.
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How can scientists deduce the number of types of neutrinos, or 'effective number', from Planck satellite data?
Is it related to the way they deduce the Hubble constant from Planck data?
Would more types of oscillating and mixing neutrinos mean faster or slower expansion of the universe?
Would a fourth mass ...
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Why does Titan's (relatively) rapid migration away from Saturn cause the planet to wobble faster, and eventually (maybe) tip onto its side?
Over the past year and a half, multiple articles in the popular press have come out talking about how unexpectedly rapidly Titan is moving away from Saturn, and how this is causing Saturn to wobble ...
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