Questions tagged [astronomy]
The science dealing with objects and phenomena located beyond Earth. In particular, this applies to observations and data. At its core, astronomy is the physically informed cataloging and classifying of the contents of the universe in order to better understand what is out there.
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Are there any experimental bounds on the ratio of neutrinos to antineutrinos in the universe?
In the Standard Model, both baryon number and lepton number are conserved quantities (excluding the theoretical possibility of sphaleron processes which are exceeding rare, at least at non-"near in ...
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How do we decode the image formed by a gravitational lens?
Using our own sun as a gravitational lens, we can scrutinize planetary surfaces in distant solar systems with a good deal of accuracy. How do we translate this smeared out and curved image into a ...
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Why is my approach to the equation of time off by a constant?
I'm trying to better understand the causes for the equation of time by deriving an approximation from first principles.
My naive approach, $EOT_{NAIVE}$, is to take the difference between the right ...
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Ephemeris calculations: Light time correction of the moon
I am currently trying to calculate apparent positions from raw JPL data.
I've got it pretty much figured out, but there is one thing that's bugging me: Has the light time correction of the moon to be ...
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How did Kepler arrive at his laws?
How did Kepler arrive at his laws? If one already knows the distances to the planets (and the eccentricity of the orbits, etc.), it is understandable that one might proceed to establish Kepler's ...
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Why are there fewer brown dwarfs than stars?
Lighter stars are more common than heavier stars, you'd think that this would make brown dwarfs more common than red dwarfs and yet they are less common by factors of a few.
(e.g. see Table 5 of ...
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How loud is the Perseus cluster?
The gas near the center of the Perseus cluster exhibits quasiperiodic pressure oscillations that can be interpreted as sound. I found a paper that says that these pressure waves have a wavelength of ...
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What is the highest-energy event "naturally" happening in the current state of the Universe?
I know the question sounds a bit broad, but I will specify it a bit more. I also don't think there is a right answer necessarily, I am just interested in the scales of different processes happening ...
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What is novel about the analysis showing that Mercury is "closer" to Earth than Venus?
Why is the recent analysis showing that Mercury and not Venus is on average the closest planet considered new?
This should surely come as no surprise to anyone who has ever looked at a plot of the ...
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What happens in the event that the cooling radius is shorter than the virial radius of a Cold Dark Matter Halo?
The cooling radius of a cold dark matter halo is defined to be the time at which the cooling time $t_{cool} = t_{free fall}$
where
$$t_{cool}=\frac{\rho \varepsilon }{\Lambda \left ( T \right )n_{H}...
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Maximum-Entropy Method deconvolution implementation?
I am looking for an implementation of the Maximum Entropy Method for image deconvolution, ideally in MATLAB or Mathematica.
I'm trying to reconstruct an image from fringe visibilities, as is often ...
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Good sources to get velocity/position vectors for all planets and moons in the Solar System for building an orbital simulator?
I’m building an $N$-body simulator, and I have everything ready to begin simulating. But my issue is is that I have no idea how to get all the starting positions and velocities for the celestial ...
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Authoritative Reference for Astronomical Constants
Is there a reference that is considered authoritative when it comes to astronomical data, especially for the planets and their satellites and the Sun?
I've been using the most recent CRC Handbook of ...
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Observational evidence for superfluidity in neutron stars
What is the earliest evidence for the existence of superfluidity in neutron stars?
I'm about to present the subject in a seminar and I'm under the impression that at the moment there is no ...
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Conceptual understanding of silk damping
CMB anisotropies are washed out below the silk damping scale, because photons travel out of overdense regions. However does silk damping also damp matter perturbations (through scattering) on scales ...
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