Astronomy Weekly Newsletter

Astronomy newsletter

Top new questions this week:

Existence of gravitons?

For a lot of my uninformed life, I have doubted the existence of gravitons or even that gravity is an actual "force" (like electromagnetism). This is because my vision of general relativity was that ...

gravity cosmology  
asked by Jack R. Woods 10 votes
answered by zibadawa timmy 9 votes

What conditions would lead to this event around the black hole in the Pictor A galaxy?

This is a picture of a jet of particles exiting the supermassive black hole in the center of Pictor A galaxy at nearly the speed of light. Source This event is supposedly created from a black hole ...

asked by CipherBot 7 votes
answered by HDE 226868 2 votes

How do star densities work?

If we take a look at stars more massive than the Sun, their densities vary a lot. UY Scuti is an extremely low-density star that's only 8.5x more massive than the Sun, but is 1000-2000x its size. ...

star sun mass stellar-dynamics density  
asked by Sir Cumference 6 votes
answered by Warrick 6 votes

Precision of geocentric gravitational constant

I am looking for an answer as to why the geocentric gravitational constant, μ, defined as the product of the gravitational constant, G, and the mass of a body (earth in this case), M, can be ...

gravity newtonian-gravity  
asked by doug5085 6 votes
answered by David Hammen 2 votes

How does an accreting black hole acquire magnetic fields?

There is actually a similar question on this site: Can magnetism escape a black hole?, however the answers do not focus on accretion, which is my main concern, so I start a new one. In Kip Thorne's ...

black-hole supermassive-black-hole magnetic-field active-galaxy  
asked by Kaius 5 votes
answered by HDE 226868 3 votes

Why do pre-main sequence stars show lithium in absorption?

This paper and this paper state without discussion that the presence of lithium absorption in the stars they observe as strong evidence of these stars being pre-main sequence stars. Because they state ...

star star-formation  
asked by Joshua 4 votes
answered by Rob Jeffries 5 votes

Why do planets move in an elliptical orbit?

I am a student of class 9 and recently came to know about kepler's law of planetary motion and got confused about the foci and elliptical orbits of planets and some stars.

asked by Babra Ejaz 3 votes
answered by userLTK 5 votes

Greatest hits from previous weeks:

How many planets are there in this solar system?

So, in school (that's a long time age) they have been teaching us there are 9 planets in our solar system. Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto But every now and then I ...

solar-system planets dwarf-planets  
asked by e-sushi 34 votes
answered by Undo 45 votes

How big would the asteroid belt planet be?

As I understand it, the asteroid belt exists because the gravitational force of Jupiter prevents the asteroids from accreting (is that a word?) into a planet. If, however, Jupiter didn't exist and ...

jupiter asteroid-belt  
asked by Scottie 13 votes
answered by Ilmari Karonen 7 votes

Can you answer these?

Are there collected data about the direction of rotation of black holes and the direction of the magnetic field?

Is there a relation between the direction of rotation of black holes or neutron stars and the magnetic dipole moment of BH or neutron stars? BTW, are there different directions of this two parameters ...

black-hole rotation magnetic-field  
asked by HolgerFiedler 1 vote

Tools and algorithms for angles-only orbit estimation

I've seen discussion threads where amateur astronomers estimate a satellite's orbital parameters from angles-only telescope observation. Are there any community tools or algorithms to help with this ...

satellite astrometry  
asked by Carl F. 1 vote

What would we not know without spectroscopy?

What do we depend on spectroscopy to know about in astrophysics? Or, without spectroscopy, what would remain unknown to us? I want to know how important it is. My wife is studying spectroscopy in ...

asked by einnocent 1 vote
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