Unanswered Questions
180 questions with no upvoted or accepted answers
0
votes
0
answers
88
views
How do I calculate the positions of an artificial satellite for a decade?
We are trying to solve what I think should be a simple question: suppose there is a satellite that is launched into a certain orbit, where will it be as a function of time? Let's say we know that it ...
- 117
0
votes
0
answers
50
views
What are the primary astrophysical implications of a proposed mass of about 11 M⊙ for the SN 2023ixf progenitor?
The abstract of the arXiv preprint SN 2023ixf in Messier 101: A Variable Red Supergiant as the Progenitor Candidate to a Type II Supernova (itself recently "discovered" in the observatory) ...
- 30.3k
0
votes
0
answers
99
views
Difficulty simulating trajectory of moon and sun for Apollo 11 mission
As an engineering student, I am doing a project about Kalman filtering and the mission Apollo 11. Now I tried to simulate the trajectory of the moon and sun for 3 days (the duration in which the ...
- 4,800
0
votes
0
answers
42
views
Trying to understand how to properly implement this equation to a healpix map
So i am working on reproducing a paper (Secrest, N. J., von Hausegger, S., Rameez, M., Mohayaee, R., Sarkar, S., & Colin, J. (2021). A test of the cosmological principle with quasars. The ...
- 20k
0
votes
0
answers
73
views
What is the galactocentric aberration?
At the Wikipedia about an aberration, there is the phrase:
a recommended galactocentric aberration constant of 5.8 µas/yr
What is the galactocentric aberration? How is it calculated correctly? An ...
- 301
0
votes
0
answers
166
views
How much would you weigh at the equator of the fastest spinning pulsar?
Assuming you have a mass of 70 kg, what would your weight be on the equator of PSR J1748−2446ad?
0
votes
0
answers
169
views
2-body orbits expanding in nbody simulation?
Recently, I designed an n-body engine and tested it with a binary star system. After a minute of running, the orbit began noticeably expanding:
Why is it happening, and is this natural? The source ...
- 6,684
0
votes
0
answers
64
views
Wrong planet orbit
I would like to calculate Mercury's orbit in Mathematica. My initial conditions, in AU and AU/year, are:
...
- 1
0
votes
0
answers
37
views
What is sonic transition of an astrophysical fluid?
My notes mention sonic transition of a fluid. Is it where the speed of the fluid elements cross the speed of sound in the medium they are located?
- 481
0
votes
0
answers
61
views
Why can't ESA/NASA build a handful of Gaia telescopes and launch them into different positions in space for better accuracy?
I've noticed that many stars in GAIA DR2 have highly uncertain distances. Why can't a space agency send multiple Gaia spacecraft into orbit around different places (One in L2 Earth, one in ...
- 6,684
0
votes
0
answers
114
views
Where can I find galaxy spectra (in the form of FITS files)?
I know there's SDSS and I tried searching for the spectra through the navigate and explore tool under CAS as well as by using RA/Dec coordinates under SAS, but every single time it comes out with 0 ...
- 41
0
votes
0
answers
82
views
Setting specific CENTER coordinates coordinate in SWARP
The SWARP Documentation specifies that we first set the CENTER_TYPE to MANUAL and then in the CENTER parameter we specify either one of the equatorial coordinates (RA, Dec). This is specified in the ...
- 21
0
votes
0
answers
50
views
The possibility of rapidly changing the Earths orbit via a passing astronomical object
I assume that the Earth could be “gently” (without colossal tidal or volcanic catastrophe) displaced by a passing extra solar star, brown dwarf or planet and end up perhaps 10% further away from the ...
- 359
0
votes
0
answers
92
views
What shape do satellites trace as they wobble in orbit around another body?
What shape does the center of gravity of a satellite trace in 3-d space as it wobbles in orbit around another body? How is this shape modeled geometrically? Is it a topological torus? Is it feasible/...
- 101
0
votes
0
answers
88
views
What was the energy/wavelength/frequency of the CMB when first emitted/released?
Given the z redshift of 1089, and the temperature difference between then and now of about 1089, I tried scaling the ev, freq. and wavelength by 1089....
Is that right?
I get a freq. of about 240 ...
- 5,327