All Questions

I understand that radio astronomers like to work in terms of Brightness Temperature, due to the various conveniences it brings mathematically. The strength of the 21cm appears to be roughly 3 orders ...

Exactly what is the non-thermal Sunyaev-Zel'dovich effect? From what I understand from reading several papers by Mark Birkinshaw and Sergio Colafrancesco, I get the rough idea that the non-thermal SZ ...

I think this picture is correct because for earth astronomical day is slightly shorter than solar day. (Is it a rule of thumb for planets? Where can I read such data?) Source So the angle between ...

The GAIA spacecraft is currently mapping the stars in the Milky Way by parallax. It orbits in the Earth-Sun L2 lagrange point. The parallax observed from the spacecraft orbiting around the sun allows ...

In this answer as well as this one, I've linked to New Jersey Institute of Technology's Dr. Dale Gary's nicely-written Physics 728 Radio Astronomy; Lecture #1 notes where I can see the image below. It ...

While I was reading about Ultima Thule, I was wondering if the discovery of contact binary objects had any effect on our current theories of how the Moon formed?

This page lists the total luminosity of the Milky Way Galaxy to be $4\times10^{10}$ $L_{sol}$, and $L_{sol}=3.86 \times10^{33}$ ergs.sec$^{-1}$; this gives a total luminosity for the MW of $1.54\...

In a paper titled Arp, H. (1984). Distribution of quasars on the sky. Journal of Astrophysics and Astronomy, 5(1):31-41. at Journal of Astrophysics and Astronomy, Halton Arp wrote that there is ...

The classic paper A MEASUREMENT OF EXCESS ANTENNA TEMPERATURE AT 4080 Mc/s begins: Measurements of the effective zenith noise temperature of the 20-foot horn-reflector antenna (Crawford, Hogg, and ...

I've just been answering a question on this issue,in physics SE,and realised that my answer conceals a point I don't myself understand. I understand that The expansion of metric isn't affected by ...

I am approaching this topic from a layman's perspective and view this as a logic puzzle, but when someone tries to get me to accept the logic, I'm never convinced by their arguments. According to ...

I have this National Geographic 76/700EQ telescope I picked up at a second-hand store for $50. Anyone know how to adjust the finder scope on it? I turn the 2 pins on the top and side but it does not ...

I was wondering if any of the asteroids we have ever seen has a hot core like Earth's. I'm thinking that Earth has a strong gravitational field and so formation would have involved a lot of ...

It is known that during Solar/Stellar Flare, plasma from the corona of the star is released into the space, and travels comparatively slowly. In an hypothetical situation, does the coronal mass also ...

I'm having a hard time understanding why there would be this ambiguity. Also, why would this be not the case if the planet was viewed pole on? Edit: "NOrth SOuth ambiguity" is a term used in a paper ...

When observing 2 objects side by side close to the horizon with a very large array, one receding fast & red shifted, is the delay to correlate the signal from the closest dishes to the further ...

Very Long Baseline Interferometry or VLBI such as the Event Horizon Telescope or JPL's delta-DOR (see below) uses baselines of the order of the Earth's diameter. Spacecraft position determination ...

I found the picture below in an answer to the post "Was the Milky Way ever a quasar". The picture is published on a website belonging to "NASA/IPAC Extragalactic Database". In the answer that has 16 "...

What I understood about it till now is that space-time fabric is kind of broken there. Please tell me whether I am correct. If it's true then does it mean that perception of time will stop there? I ...

Based on what I know, the Earth accreted out of the solar nebula, had a period when it was entirely molten, and then slowly cooled. Could a planet form without ever passing through a molten phase?

@RobJeffries' answer to the question Does gravitational lensing provide time evolution information? points out that there can be a substantial different in arrival times of light from a given source ...

The question Does gravitational lensing provide time evolution information? is excellent! When we see multiple images of the same object because of the phenomenon of gravitational lensing, do all ...

I found three NASA JPL images in the sequence PIA23133, PIA23134, and PIA23135. They were taken by the Curiosity Rover on Mars and show solar eclipses by Mars' two moons. Details of these images are ...

When we see multiple images of the same object because of the phenomenon of gravitational lensing, do all the images show the lensed object at the same point in time? Does it take the same amount of ...

Much of the Earth's atmosphere has a scale height $h$ of roughly 7 to 8 kilometers such that the local density varies as $\exp(-(r-r_0)/h)$ where r is the radius vector and $r_0$ would be some ...

Given a right ascension in degrees and declination in degrees (say, 88 degrees RA, -63 degrees DEC) I want to find the angle between that location and the ecliptic pole (90 degrees RA, -66 degrees DEC....

In 2010 observations with the Fermi Gamma-ray Space Telescope discovered giant bubbles which have been named Fermi Bubbles. Similar structures have also been discovered by Pshirkov et al. (2016) ...

Having the solar flare fluxes on the two bands of GOES (0.05-0.4 nm and 0.1-0.8 nm) I need to calculate the flux between 0.05 and 0.2 nm.

Why is the outer section of the sun convective but the inner section stable and only radiative? They are both made up of the same kind of matter, both heated by the core.

I'm interested in the learning about the local densities around galaxies. I've found myself a bit confused on how to relate angular distances (arcseconds) with physical distances (parsecs) when ...

I am having a slight disagreement with my professor. We can measure the mass of a distant star cluster from: A.Its color B.Its radius C.Its metallicity D.Smearing of lines in ...

I am a statistician with love and passion for astronomy. I try to explain some outliers I found in the values of quasars - color indexes. I found four (4) values close to twenty (20). Is that ...

Assume that the expansion of the universe stops and it starts to contract again. What would happen? Would only distances between objects get smaller, or are there other effects we can expect?

As we see every day in the morning the sun shows a red-orange colour but at midday has a blue-white like colour why? Is it concerned with the distance from the earth or about intensity? How do you ...

I am looking for a list of all known identifiers used for stars. I'm not sure on the terminology. While I do want the "proper names", I also want whatever identifier is used for each star detected, ...

I just read the BBC News article Exoplanet tally set to pass 4,000 mark . It makes me wonder about the annual rate that new exoplanets being recognized, and how it compares to the rate of new ...

I read that we can observe [OIII] from AGNs but what processes in AGNs produces these lines why we can use them to trace or tell if that galaxy is active or not?

I'm given this set of data and I need to describe the habitability. Would this not be habitable since the temperature of the albedo and the equilibrium is similar to Earth's or does the Spectral Type ...

I've been told white dwarfs don't produce stellar wind like the sun produces solar winds. I don't quite understand why that is and can't really find any evidence that confirms or denies that. My ...

I'm having a difficult time understanding certain behaviors of white dwarfs. I understand how mass is lost in the red giant to white dwarf transition process. I understand that white dwarfs can ...

Wikipedia's Red Giant page says they range in mass from 0.3 to 0.8 solar masses. Which corresponds to an initial mass of a bit less than 1 solar mass, about 0.8 or so, if I was to estimate and a few ...

Given our real solar system how would planet orbits plot look like if we fix earth in the middle (put earth in the middle and draw a real orbit of a given planet) ? What would be the shape of its ...

I've realized the transit of an exoplanet. Now, I want to fit the points I obtain to study the light curve of the transit. But i don't now what math function I can use to do that. Do you have any idea ...

I am trying to draw an orbit using the Transform3DGroup class in the C# .NET framework. I have orbital elements a, e, i, RAAN, ArgPer, trueAnom. The algorithm that spits these out for me also gives me ...

I'm trying to create a geodesic dome with the stars of the northern night sky inscribed on the outside. The highest point of the dome would be the celestial north pole. How do I create a map that ...

The NY Times article Saturn’s Rings Are Sculpted by a Crew of Mini-Moons is really interesting and links to the recent paywalled paper in Science Close Cassini flybys of Saturn’s ring moons Pan, ...

Come to think of it, the only things we hear about degeneracy is neutron and electron. I made a generalization: White Dwarf: Supported by electron degeneracy. Neutron Star: Supported by neutron ...

In the graphs in my previous question here, there are negative-sloped regions as the colour-z relationship oscillates. So if I look at how the I-W2 and W3-U colours change with redshift, as I've done ...

In this paper, the authors describe the theoretical relationship between photometric colours, particularly in Figures 1 and 6: Since the colour is the difference between two magnitudes, and the ...

According to this video stars at end of time and many others on fate of universe they all agree on one thing that stars will eventually convert all the hydrogen into heavier elements and eventually ...