Answer:

• It is the right distance from the Sun, it is protected from harmful solar radiation by its magnetic field, it is kept warm by an insulating atmosphere, and it has the right chemical ingredients for life, including water and carbon.
• The largest supermassive black hole in the Milky Way's vicinity appears to be that of Messier 87 (i.e. M87*), at a mass of (6.4±0.5)×109 (c. 6.4 billion) M ☉ at a distance of 53.5 million light-years.

1) The universe through the eyes of an astronomer or astrophysicist is a fascinating place — and a good book can give you a glimpse of that world without requiring years of study. Here are the Space.com writers' and editors' recommendations of astronomy and astrophysics books that will thrill, puzzle, intrigue and blow your mind.

2)

special planet: the habitable Earth

What makes the Earth habitable? It is the right distance from the Sun, it is protected from harmful solar radiation by its magnetic field, it is kept warm by an insulating atmosphere, and it has the right chemical ingredients for life, including water and carbon.

3) Cygnus X-1 is the heaviest stellar black hole observed without using gravitational waves. The famed Cygnus X-1 black hole (illustrated, slurping mass off its companion star) is nearly 1.5 times as massive as astronomers thought, new observations suggest.