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Jun
23 |
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Why don't stars 0.5<m<0.8 solar masses undergo a helium flash? I'm not sure this claim is true. The 0.8 solar mass "limit" may just be the lowest mass stars considered that have had a chance to evolve to He burning in our universe. |
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Jun
21 |
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Is there a Dark Matter Paradox? added 102 characters in body |
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Jun
20 |
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answered | Is there a Dark Matter Paradox? |
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Jun
19 |
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What happens to planets as they cross the Galactic equator? @Walter The well-known and used SHM approximation gives a vertical period of 90 Myr for the Sun, with an amplitude far bigger than 20 pc. How far is that off the "correct" value? |
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Jun
19 |
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awarded | Good Answer |
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Jun
18 |
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Redshift of distant galaxies: why not a doppler effect? @KamilSzot and yet Hubble's law yields $v > c$. |
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Jun
17 |
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answered | What is emission line ratio? |
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Jun
13 |
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awarded | Enlightened |
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Jun
12 |
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awarded | Nice Answer |
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Jun
12 |
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answered | Is Earth's Atmospheric Thickness Related to Cosmic Ray Radiation? |
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Jun
12 |
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What pulls the Sun above the galactic plane and pulls it below the galactic plane? deleted 42 characters in body |
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Jun
12 |
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What happens to planets as they cross the Galactic equator? edited body |
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Jun
12 |
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What happens to planets as they cross the Galactic equator? @Walter How so? The epicyclic approximation for near circular orbits is a totally standard bit of galactic dynamics isn't it? The SHM approx is good so long as you can assume the density is constant. Hence as long as the vertical amplitude is less than the vertical scale on which the density varies. galaxiesbook.org/chapters/II-03.-Orbits-in-Disks.html (Sec 10.3.1). Which is what I said. |
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Jun
11 |
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What happens to planets as they cross the Galactic equator? added 65 characters in body |
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Jun
11 |
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What happens to planets as they cross the Galactic equator? added 915 characters in body |
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Jun
10 |
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What happens to planets as they cross the Galactic equator? added 26 characters in body |
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Jun
10 |
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What happens to planets as they cross the Galactic equator? deleted 12 characters in body; edited tags; edited title |
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Jun
10 |
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What happens to planets as they cross the Galactic equator? added 187 characters in body |
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Jun
10 |
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What happens to planets as they cross the Galactic equator? There is a reasonably well-defined mid plane and the Sun is above it and being accelerated back towards it. The thickness isn't really relevant (other than to make SHM a better approximation). |
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Jun
10 |
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answered | What happens to planets as they cross the Galactic equator? |