Recent content by MarkL
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Undergrad Integrating discs to find the gravitational force of a sphere
If anyone is interested... The equation for the ellipse is ## x^2/a^2 + y^2/b^2 = 1##, ##a > b##. Substituting ##a## for ##d## above and solving for ##y##, the equations become \begin{align*} & 2\pi Gm\sigma \int_{-a}^{a}[1 - \frac{(a-x)}{\sqrt{(b^2-(b^2/a^2)x^2)+(a-x)^2}}]dx \\ \text{or} \\ &... -
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Undergrad What Prevents Electrons from Expanding Radially in White Dwarfs?
Your last paragraph would never influence an electron with enough pressure to support the mass of a star. Your first paragraph, however, is spot on and intuitive. And I'm good...thanks for your response.- MarkL
- Post #8
- Forum: Astronomy and Astrophysics
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Undergrad What Prevents Electrons from Expanding Radially in White Dwarfs?
the answer above was: "restoring force bringing back neutrality" Does this mean, bring back (to neutrality) = zero electron expansion or prevents electron expansion or expand till (neutrality) = electrons expand till force equals fermi pressure = some electron expansion- MarkL
- Post #6
- Forum: Astronomy and Astrophysics
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Undergrad What Prevents Electrons from Expanding Radially in White Dwarfs?
bring back...or expand till- MarkL
- Post #4
- Forum: Astronomy and Astrophysics
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Undergrad What Prevents Electrons from Expanding Radially in White Dwarfs?
From Wikipedia : White dwarfs resist gravitational collapse primarily through electron degeneracy pressure What prevents electrons from expanding radially through the space between the ions (carbon, say)?- MarkL
- Thread
- Replies: 7
- Forum: Astronomy and Astrophysics
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High School Coulomb pressure and concentric spheres
Suppose you have a sphere of radius a of positive charge, and a concentric shell from a to b of negative charge. The positive charge is equal to the negative charge. (non-conducting, uniform density) Is there an outward pressure at a of kqq/a2/(4πa2) - with pressure decreasing with radius...- MarkL
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- Coulomb Pressure Spheres
- Replies: 1
- Forum: Electromagnetism
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Stargazing Understanding the Chandrasekhar Mass Units for Relativistic Lane Emden Equations
I guess I can't delete...- MarkL
- Post #5
- Forum: Astronomy and Astrophysics
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Stargazing Understanding the Chandrasekhar Mass Units for Relativistic Lane Emden Equations
a is in Lame Emden equations --- as in, r = a ξ- MarkL
- Post #4
- Forum: Astronomy and Astrophysics
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Stargazing Understanding the Chandrasekhar Mass Units for Relativistic Lane Emden Equations
Thank you - I discovered my mistake. I will delete this post shortly.- MarkL
- Post #3
- Forum: Astronomy and Astrophysics
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Stargazing Understanding the Chandrasekhar Mass Units for Relativistic Lane Emden Equations
Using Lane Emden and n = 3 (relativistic), I calculate the correct mass -- the Chandrasekhar mass (about 1.4 Msun) The equation goes Mtotal ∝ a3, because at n=3, the density, ρ, cancels out. a2 ∝ K/G = Kg2 → a3 ∝ Kg3. Here K ∝ h c or Kg m3/sec2 and G ∝ m3/Kg/sec2 This implies the mass, Mtotal...- MarkL
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- Mass Units
- Replies: 5
- Forum: Astronomy and Astrophysics
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Undergrad Why does Webb orbit L2, is it because of the Moon?
Why not place it on the moon?- MarkL
- Post #14
- Forum: Astronomy and Astrophysics
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Undergrad What happens to the material not involved in the core collapse of a supernova?
supernova remnant...duh! https://en.wikipedia.org/wiki/SN_1987A looks more controlled...like a smoke ring thanks- MarkL
- Post #5
- Forum: Astronomy and Astrophysics
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Undergrad What happens to the material not involved in the core collapse of a supernova?
What happens to the material not involved in the core collapse of a supernova? This would be the outer portion of a star or any cloud that surrounds the star. All material to infinity or does some material remain close -- gravitationally close that might collapse if it could. thanks- MarkL
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- Collapse Core Material Supernova
- Replies: 4
- Forum: Astronomy and Astrophysics
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Undergrad Trying to get a physical understanding of a Fermi gas
I would like to get a more physical interpretation of conduction electrons (fermi gas) in a metal. I imagine ionized valence electrons close to the ions, with the fermi level (highest energy electrons) of the gas participating in conduction. A point of confusion for me...the first ionization...- MarkL
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- Fermi Fermi gas Gas Physical
- Replies: 2
- Forum: Quantum Physics