Unanswered Questions
48 questions with no upvoted or accepted answers
7
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How do I calculate the Hill radius of a star in a binary system?
Is there an easy way to calculate the Hill radius of a star in a binary system at different orbital radii where both stars are of the same mass and in circular orbit around one another’s centre of ...
- 30.7k
7
votes
0
answers
315
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Gravitational eddies across the galaxy?
I read about natural gravitational eddies that travel in a wave that black holes have. They also have a strong magnetic field. Does those eddies follow magnetic field lines of the rotating black hole? ...
- 1
6
votes
0
answers
150
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Semimajor axis variations in co-orbital moons
I've been playing with simulations of co-orbital bodies similar to Saturn's moons Janus & Epimetheus- horseshoe orbits where the two bodies are of comparable mass- and I'm seeing some very odd ...
4
votes
0
answers
111
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Calculating the "Turnaround Point," where expansion dominates over gravity
I'm trying to understand the point where the expansion of space dominates over gravity, but I'm coming up empty handed when searching the internet. Specifically, I'm trying to find the math for it. I'...
- 3,873
4
votes
0
answers
115
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Do differentials in the Earth's density cause the flyby anomaly?
The flyby anomaly is an occasional, unpredictable, and as yet unexplained discrepancy in acceleration of satellites when they pass close by the Earth. It causes an increase of up to 13 mm/s during ...
4
votes
1
answer
208
views
Gravitational influence of other planets?
I have a friend who believes in astrology and she insists that the gravitational influence of the planets has an effect on the child when it's born. The last time she was going on about this a thought ...
- 1,797
3
votes
0
answers
68
views
Gravitational recoil with stars/planets...?
When two black holes are merging, the resulting merge can be ejected if one of the black holes had less mass than the other one, so the gravitational waves emitted by both of them is unbalanced, and ...
- 1,017
3
votes
0
answers
95
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Kinetic energy in cosmology?
Spacetime expands at an accelerated rate due to the Hubble flow. In many papers that I've read, objects coupled to the Hubble flow are treated as if they have some velocity and kinetic energy ...
- 1,017
3
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0
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78
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How much mass to make a shperical object?
I was googling around for info for D&D campaign I am going to run. I was wondering about the mass required for a object to pull itself into a shperical shape and it seems that the answer varies ...
3
votes
0
answers
173
views
New evidence against the existence of dark matter?
I've just read and heard about an article which gives new evidence for MOND - Modified Newtonian Dynamics, which is an alternative to dark matter by proposing that our gravitational law should be ...
- 5,626
3
votes
0
answers
119
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Gravity on Mercury's highest elevation?
This post answers what is Mars' gravity at its highest point (Olympus Mons) compared to the Earth's and Mars' standard, it's 0.3736 g (Mars standard is 0.3794 g). This also seems to be the lowest ...
- 30.7k
3
votes
0
answers
357
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How does the size of a naked black hole effect its photon sphere?
What effect does the size of a black hole have on the size or density of the photon sphere and it's proximity to the horizon?
For example: A person is in space looking at 2 black holes, one of them ...
- 1
2
votes
0
answers
34
views
Local anisotropies in the expansion of the universe and tidal forces...?
In the context of the large-scale structure of the universe, there can be local anisotropies (https://www.aanda.org/articles/aa/full_html/2021/05/aa40296-21/aa40296-21.html).
I understand from this ...
- 1,017
2
votes
0
answers
110
views
Velocity of the object in Binary system
how to i can calculate the velocity of the object? If i know the distance of the object from the center of mass, and i know distance between the two (identical) ellipse center... (the two object has ...
2
votes
0
answers
47
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Is frame dragging expected to be quantized in a theory of quantum gravity?
Protons and electrons have angular momentum which is quantized. Would the angular momentum of black holes be quantized in quantum gravity? Would this then affect Hawking radiation?
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