Ask Astro | Page 4 of 21 | Astronomy.com

Merging black holes

When black holes merge, is the diameter of the new black hole bigger?

There isn’t a scale large enough to weigh galaxies like NGC 7714. ESA, NASA; Acknowledgement: A. Gal-Yam (Weizmann Institute of Science)

Ask Astro: How do scientists weigh planets and other celestial objects?

HST image of Jupiter near opposition

Science, Solar System

How old is each planet in our solar system?

Artist's concept of Planet X

Could we find Planet Nine using JWST?

Location of Jupiter's Trojan asteroids

How closely packed are Jupiter’s Trojan asteroids?

When stars “die,” they leave one of two objects behind. Massive stars explode as supernovae, creating remnants of gas and dust like the Crab Nebula (M1). Credit: ASA, ESA, J. Hester and A. Loll (Arizona State University)

Milky Way, Stars

How many stars die in the Milky Way each year?

The very center of globular cluster NGC 6397

How do globular clusters remain intact for so long?

The makeup of the universe

Are the percentages of dark matter and dark energy stable?

Credit: NASA/JPL-Caltech.

Exotic Objects, Galaxies

How does a black hole get to the center of a galaxy, and does the galaxy revolve around it?

Albireo

Why are there no green stars?

Active Region 13055 on the Sun

Solar System, Stars

What causes sunspots?

Mars InSight solar panel covered with dust

Robotic Spaceflight

Why doesn’t NASA build a mechanism to clean the solar panels on its Mars rovers?