How does a star form a black hole? How does scientists detect black holes?
**How do stellar black holes form?**

Stellar black holes form when the center of a very massive star collapses in upon itself. This collapse also causes a supernova, or an exploding star, that blasts part of the star into space. Scientists think supermassive black holes formed at the same time as the galaxy they are in.

**How do scientists know they are there?**

A black hole can not be seen because of the strong gravity that is pulling all of the light into the black hole's center. However, scientists can see the effects of its strong gravity on the stars and gases around it. If a star is orbiting a certain point in space, scientists can study the star's motion to find out if it is orbiting a black hole.

When a black hole and a star are orbiting close together, high-energy light is produced. Scientific instruments can see this high-energy light.

A black hole's gravity can sometimes be strong enough to pull off the outer gases of the star and grow a disk around itself called the accretion disk. As gas from the accretion disk spirals into the black hole, the gas heats to very high temperatures and releases X-ray light in all directions. NASA telescopes measure the X-ray light. Astronomers use this information to learn more about the properties of a black hole.
How do black holes die, and can anything stop a black hole, apart from a larger black hole?
After analyzing and comparing different solutions, it appears that nothing can truly stop a black hole apart from a larger black hole. However, there are different ways in which black holes can die.

One possibility is through a process called Hawking radiation, named after physicist Stephen Hawking. This occurs when pairs of particles and antiparticles are created near the event horizon of a black hole. If one of these particles falls into the black hole, while the other escapes, the escaping particle has effectively stolen some energy from the black hole. Over time, this can cause the black hole to evaporate.

Another possibility is through a process called mergers, in which two black holes collide and merge into a larger black hole. This can happen when two galaxies merge, or when two black holes in a binary system spiral towards each other and merge.

In summary, while nothing can truly stop a black hole apart from a larger black hole, black holes can die through processes such as Hawking radiation and mergers.