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12 votes
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Does the existence of hydrogen in the universe create an obscuration effect similar to the way air does at great distances?

One way of thinking about this is in terms of the physics of the cosmic microwave background. The cosmic microwave background occurs as a phenomenon when a nearly homogeneous universe transitions ...
ProfRob's user avatar
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10 votes
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Measures for the degeneracy from protons?

Stars are electrically neutral. In the optimal case for proton degeneracy, a star is made of hydrogen, maximising the proton number density. The number density of electrons is exactly the same. Since ...
ProfRob's user avatar
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6 votes

Does the existence of hydrogen in the universe create an obscuration effect similar to the way air does at great distances?

In a sense yes - there is interstellar (i.e. intra-galactic) absorption of Lyman-$\alpha$ photons by neutral hydrogen. This plays a role e.g. when trying to determine how much hydrogen is lost from ...
AtmosphericPrisonEscape's user avatar
5 votes
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why couldn't atoms form in the early big bang?

In an atom, the electrons are held around the nucleus by electromagnetic forces. The electrons have a negative charge, and the nucleus has a positive charge, and these attract. But if you give the ...
James K's user avatar
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4 votes
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Solar flare generate energetic protons. Where do the electrons go?

The solar wind, and more generally plasma in space is not charged on average; it is electrically neutral. That means you have the positively charged ions and the corresponding amount of electrons. In ...
planetmaker's user avatar
4 votes
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Is there a connection between the solar wind and the cosmic radiation?

Cosmic radiation (which consists of high-energy protons and atomic nuclei) comes from the sun, other stars, even other galaxies. Solar wind is a part of that - the part coming from the sun, which ...
Rory Alsop's user avatar
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4 votes
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Is it true that black holes emit only photons, electrons, and positrons in the form of Hawking Radiation?

When you look at Hawking's 1974 Nature paper (https://www.nature.com/articles/248030a0), it is very clear that like thermodynamic blackbodies, black holes can emit anything they want. Or to be more ...
Viktor Toth's user avatar
2 votes

Is there a connection between the solar wind and the cosmic radiation?

Generally, high solar activity deflects or absorbs truly cosmic rays. There's an eleven year cycle in the intensity of extrasolar cosmic rays reaching the earth.
Wayfaring Stranger's user avatar
2 votes

Measures for the degeneracy from protons?

Another way to think of the answer is that the pressure of any nonrelativistic gas (degenerate or ideal) is always 2/3 the kinetic energy per unit volume. So we can say that when the electrons go ...
Ken G's user avatar
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2 votes

Solar flare generate energetic protons. Where do the electrons go?

Their destination might be possibly either of Winding up one way mission to the space and the speeding particle is free of the Earth's magnetic field, and if the collision happens to set it on a ...
Aung Satt's user avatar
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1 vote
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In the case of heat death of our universe, would proton decay overtake the singularity decay due to Hawking radiation?

It's likely that the "existence of a proton" has no meaning inside the event horizon. But if it does somehow, and the protons eventually decay, that would be invisible outside the black-...
antlersoft's user avatar
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1 vote

How is the H II 'region' directly detectable? By Compton or Thomson free-particle scattering? At what wavelengths?

HII regions or emission nebulae are associated with the presence of massive stars that ionize the gas. The strongest emission line from an HII region comes from H-alpha. What happens in this case is ...
Astroturf's user avatar
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