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7 votes

Is it theoretically possible for the Sun to go dark?

The answer is yes, for a small time interval $\tau$ seconds, there is a probability $\sim \exp(-10^{45}\tau)$ that no photons are emitted by the Sun. Photons do not take millions of years to find ...
ProfRob's user avatar
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10 votes

Is it theoretically possible for the Sun to go dark?

This is spontaneous reversal of entropy. It happens at Planck times and Planck lengths, but for macroscopic events, the likelihood is the product (not sum) of the particle event probabilities, all of ...
Miss_Understands's user avatar
33 votes
Accepted

Is it theoretically possible for the Sun to go dark?

Is it theoretically possible for a statue to wave at you? After all the atoms in a statue are moving randomly, so they could (by chance) all move in the same direction. This doesn't happen. It is the ...
James K's user avatar
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2 votes

What does the surface of a star with a radiative envelope look like?

We do have some images of stars with a radiative envelope. Altair has a mass of 1.86 solar masses. We do have an image of it: There aren't any convective granules visible in this image, but the ...
Astrovis's user avatar
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3 votes

python question-discrepancy between number of stars found

When you apply the fractional distance uncertainty condition, you create a new array called final_filtered_data. But then in the next lines, you go back to using ...
Eric Jensen's user avatar
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1 vote

python question-discrepancy between number of stars found

(If you haven't found the flaw yet) I notice you're using the bit-and operator |&| in several places where the logical-and operator |and| surely is more appropriate. That can lead to unexpected ...
Salt's user avatar
  • 111
11 votes
Accepted

Are spectral subtypes a logarithmic scale, or a linear one?

Strictly speaking, neither. The types and sub-types are qualitatively defined in terms of spectral features (the presence or absence of various lines) and the relationship to photosphere temperature ...
James K's user avatar
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1 vote

When a star enters a red giant phase, does the pressure in its core increase or decrease?

A red giant is really, really different than the sun. A red giant is basically two stars, one inside of the other- and the inner one is tiny and has a substantial fraction of the mass. Here is the ...
QuadmasterXLII's user avatar
8 votes
Accepted

When a star enters a red giant phase, does the pressure in its core increase or decrease?

Newton's shell theorem tells you that what is outside the core has no gravitational influence on what is at the core (as long as the envelope is spherically symmetric). The equation of hydrostatic ...
ProfRob's user avatar
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9 votes

When a star enters a red giant phase, does the pressure in its core increase or decrease?

If you heat up a balloon, the balloon will expand. Is the balloon's internal pressure higher? Yes. Is the balloon less dense? Also yes. Is this a contradiction? I think what you aren't seeing is that ...
Darth Pseudonym's user avatar
3 votes
Accepted

What was the first nebulae of the first class?

Following the links on the Wikipedia page leads to Jones, K. G., “The search for the nebulae - VI.”, Journal of the British Astronomical Association, vol. 79, pp. 213–222, 1969., which identifies each ...
James K's user avatar
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