Unanswered Questions
180 questions with no upvoted or accepted answers
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Why are triple conjunctions in a resonance forbidden?
I was reading the Wikipedia article about orbital resonance and noticed that Laplace resonances forbid triple conjunctions. This seems to be supported by the Io-Europa-Ganymede system and the Nyx-Styx-...
- 30.3k
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Is it possible to infer information about the structure of the universe beyond the observable one?
Is it possible to infer information about the structure of the universe beyond the observable one, by observing its effects on the parts we can see? Can for example gravity from sources we cannot see ...
- 2,522
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Cosmology context plotting : Covariance matrix - Script to plot Omega_m vs Omega_Lambda diagram in Python
I have covariance matrices and Markov chains coming from the SCP (Supernova Cosmology Project) and I would like to plot all these data
in the particular diagram Omega_Lambda vs Omega_m or w vs Omega_m....
CommunityBot
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What's the formula for change in argument of periapsis over time due to J2 perturbations for a geocentric satellite?
I'm trying to propagate the orbit of the ISS, but it became very clear to me very quickly that the J2 perturbations were nothing to scoff at.
A quick google search gave me the equation for the change ...
- 21
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What is the sun's maximum influence on a magnetic object?
How much magnetic repulsion could the sun's magnetic field produce on an magnetic object? Consider the object is ideal: It could be flat, to create more resistance, balanced, to stay on the opposing ...
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Looking for analytical expression of Cosmic Variance - Poisson distribution?
I have an expression of Matter Angular power spectrum which can be computed numerically by a simple rectangular integration method (see below). I make appear in this expression the spectroscopic ...
CommunityBot
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Orbital resonance 2:1
I considered the motion of an asteroid around the sun, in a $2:1$ orbital resonance with Jupiter. Following the study of this resonance, it was observed that the angle between the major axis of the ...
- 153
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Poisson noise for a squared contrast of density - expression of variance equal to $1/n^2$
I manage to compute the Poisson noise of a density field like this :
If I take $N$ the density of galaxies and compute the Shot noise with a Poisson distribution, I get :
$\langle N^2\rangle - \...
CommunityBot
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118
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Planets orbit fitting
I would like to fit planets orbits. To do this, I need a set of mock observations. I can get them from right ascension/declination obtained from the Horizons interface:
EDIT:
Horizons gives me a list ...
- 21
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Anatomy of a galaxy cluster: understanding the relationship between dark matter halos and subhalos and galaxies within the clusters?
In my understanding, galaxy clusters contain dark matter halos, which in turn contain subhalos, and the subhalos are what surrounds individual galaxies. I know that is a simplified picture, but I am ...
- 30.3k
2
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Moon's and nodes' inclination to the Invariable plane
Moon is inclined to the ecliptic 5.14 degrees. Earth's inclination to the invariable plane is 1.57869 degrees.
What is the Moon's, and node's inclination to the invariable plane?
Since the Moon has an ...
- 545
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How is solar radiation pressure included in the SGP4 orbital propagator?
TLE sets serve as input elements for the SGP4 orbital propagator. Several orbital perturbation effects are considered in the SGP4. However, it is not obvious to me how (or if) the solar radiation ...
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Demonstration of scales for the two components (transverse and perpendicular) of Baryonic Acoustic Oscillations (BAO)
I transfer here a post that has not had any answer pn physics exchange, so I am going to delete this latter. Maybe I will have more luckiness here.
In an astrophysics context about BAO (Baryonic ...
CommunityBot
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How thick are the intergalactic filaments?
Recently, in October, news came out about the faint intergalactic filaments finally being 'found'.
Then, in June, astronomers announced that these things had enough normal matter in them to solve the '...
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How common is it for large objects (few kilometers wide) in a young protoplanetary disk or debris disk to collide with one another?
If enough time has passed for gravitational forces to allow the formation of planetesimals(proto-planets) in orbit around the proto-star, how likely is it that two of them would collide with one ...
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