37
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Accepted
At the Big Bang, when everything was close together, why did it not "collide", violating Planck length or Pauli Exclusion Principle?
The Pauli Exclusion Principle forbids two indistinguishable fermions occupying the same quantum state. It does not prevent them getting arbitrarily close together so long as they have very different ...
- 146k
32
votes
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Does matter accumulate just outside the event horizon of a black hole?
Yes, you are absolutely right, from OUR VIEWPOINT it does.
From Kip Thorne's book "Black Holes and Time Warps: Einstein's Outrageous Legacy."
Like a rock dropped from a rooftop, the star’s ...
- 498
28
votes
What's the percentage of strange matter inside a star at any time?
Zero. Normal stars are not dense enough to produce strange matter. They have regular matter only (neutrons and protons).
Strange matter has been hypothesized to form inside neutron stars, but this is ...
- 4,371
24
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Could there be dark matter black holes?
The problem with trying to form a black hole with dark matter is that dark matter can only weakly interact (if at all) with normal matter and itself, other than by gravity.
This poses a problem. To ...
- 146k
16
votes
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Is normal matter always accompanied by dark matter and vice versa?
We lack the precision to say that there aren't regions where there is matter without dark matter or vice-versa. But what is clear is that the ratio of dark matter to normal matter, which is (or needs ...
- 146k
13
votes
Does matter accumulate just outside the event horizon of a black hole?
We need to think about just where the time dilation effect occurs. By then thinking about the observations from each point of view, that is the free falling object and the external observer, we can ...
- 269
10
votes
Could there be dark matter black holes?
As pointed out by Rob Jeffries, forming a black hole (BH) from dark matter (DM) is impossible (unless there is a [hypothetical] interaction by which dark-matter can lose energy that evades all ...
- 5,526
10
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What's the percentage of strange matter inside a star at any time?
Let me first underline two specific definitions of @Alexandre:
We are looking for "matter", that means a finite region in space in thermal equilibrium.
And we are looking for "...
- 116
9
votes
Is there any proof of space being created?
This is an intriguing proposition, but I would ask how your hypothesis explains that the universe appears to be flat? That is with $\Omega_M + \Omega_\Lambda = 1$. The evidence for this comes from ...
- 146k
9
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Does matter accumulate just outside the event horizon of a black hole?
Several wonderful yet technical answers have been given, and I cannot add anything to those very nice answers that explain why it is not useful to think black holes get "frozen" at their event ...
- 5,300
9
votes
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Do we know how old the matter that makes us is?
The material (heavier than helium) that makes up the solar system was made in millions, if not hundreds of millions of stars that lived and died in the ~7 billion years between the formation of the ...
- 146k
9
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How is observable matter distributed in the universe?
I think the following is a fair summary. It's based on a fairly old study by Fukugita & Peebles (2004) but the numbers are quite reasonable. Your guess about stars dominating is way off. Most of ...
- 146k
9
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Are liquids the rarest state of matter in the universe?
No, by far the rarest state of matter in the universe is Bose-Einstein Condensate. As far as we know BECs do not naturally occur anywhere in the Universe, and have only been realized under lab ...
- 2,511
8
votes
Accepted
What explains the existence of energy/matter if it cannot be created or destroyed?
That's a very complicated question!
First, let's remember that Moses didn't bring the Law of Conservation of Energy down from Sinai on stone tablets -- it's something that we've observed to be true ...
- 7,580
7
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Does matter accumulate just outside the event horizon of a black hole?
Thought provoking cosmologists!
I'm uber-late to this discussion as I see it has been ongoing for literally years and don't know if there is still anyone monitoring this thread, but here goes.
I ...
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7
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Scenarios: Abusing a black hole
Black holes are not "made of matter". They are better described as structures of gravity/warped spacetime. However, they do grow when absorbing things with positive mass-energy.
Antimatter still has ...
- 14.4k
7
votes
Absorption of light by matter
It is the other way around.
An isolated, point-like charged particle like an electron cannot absorb a photon. It is forbidden, because energy and momentum cannot be simultaneously conserved. Only ...
- 146k
6
votes
Accepted
What percentage of the hydrogen today has never been in a star
About 70% of the baryonic matter in the universe is hydrogen, with a mean density of about $4\times 10^{-29}$ kg/m$^3$.
Most of the stars that have ever been born are still alive, since an average ...
- 146k
6
votes
Accepted
Why isn't the black hole white?
What's going on here is that you have been misled into thinking the ring-like structure has anything to do with the accretion disk. It doesn't, or at least only indirectly.
The disk is referred to as ...
- 146k
5
votes
Could there be dark matter black holes?
Black holes are the result of mass so concentrated that gravity does not let anything out, including light. Just about the only things we know about dark matter is that it has mass and seems to only ...
- 1,070
4
votes
Accepted
Why Helium could be produced in first minutes of big bang but not heavier elements
The triple alpha process requires very high densities, very high (but not too high) temperatures, and a good amount of time. Large stars have all three. In particular, they have millions of years ...
- 33.5k
4
votes
How does gravity interact with a photon?
What we call "gravity" is really just the distortion of spacetime. If spacetime was completely straight, there would be zero gravity. But the existence of a massive body is one of the things that can ...
- 18.1k
4
votes
Does matter accumulate just outside the event horizon of a black hole?
As I understand it, the presence of an event horizon (EH) from gravitational collapse is a case in which GR violates local causality in the outer (w.r.t. EH) universe. By Birkhoff theorem the EH can ...
4
votes
Is there any proof of space being created?
As is always the case in physics, there is no proof.
But if your scenario were true, it would have to be rather fine-tuned in order to create the observed expansion of the Universe.
First of all, ...
- 37.1k
4
votes
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Are we made of stars we're seeing?
Stars really are immensely far, however it's a common misconception that the stars that you can see are millions of light years away. Most of the visible stars are a few tens to a few hundreds of ...
- 116k
4
votes
Conversion of matter into antimatter
It would be more accurate to say that a black hole eventually turns whatever falls in it into equal quantities of matter and antimatter.
The difference between matter and antimatter is defined by ...
- 7,874
4
votes
Is the dark matter just regular matter out of the observable universe?
Scientists do not know what dark matter is. It is a placeholder name. It is called "dark" for two reason:
If it exists, it interacts at most very weakly with electromagnetic radiation. It ...
- 33.5k
4
votes
Is the dark matter just regular matter out of the observable universe?
If dark matter exists (rather than some strange rewrite of physical laws), then it is required to be all around us. It could not be simulated by the effects of normal matter at great distances.
There ...
- 146k
3
votes
Conversion of matter into antimatter
I'm assuming that by "inside the black hole" you mean inside the event horizon. In that case, the answer is no. The local space of a particle inside the event horizon is the same as outside - The ...
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