Tawny ZamudioBlack Holes

What is a Black Hole?Black holes are the evolutionary endpoints of

stars at least 10 to 15 times as massive as the sun.

Cont.If a star that

massive undergoes a supernova

explosion, it may leave behind a fairly

large burned-out stellar remnant.

With no outward forces to oppose

gravitational forces, the remnant will

collapse in on itself. The star eventually

collapses to the point of zero volume and

infinite density, creating singularity.

Around the singularity is a region where the force of

gravity is so strong that not even light can escape it.

No information can reach us from this region. This is why it is called a black hole.It’s surface is called the Event Horizon.

History…The idea of a body so massive that even light

couldn’t escape was first put forward by geologist, John Michell.

If the semi-diameter of a sphere of the same density as the Sun were to exceed that of the Sun in the proportion of 500 to 1, a body falling from an infinite height towards it would have acquired at its surface greater velocity than that of light, and consequently supposing light to be attracted by the same force in proportion to its vis inertiae, with other bodies, all light emitted from such a body would be made to return towards it by its own proper gravity.

—John Michell

What types of black holes are there?

Often, black holes look very different from each other, but this is because of their surroundings.

Black holes themselves are identical, except for three characteristic properties:

The massIt’s spinIt’s electric charge

Astronomers can measure the mass of black holes by studying the materials that orbits around them.

So far, astronomers have found two types of black holes:

Stellar-massSupermassive

Stellar-mass black hole

Supermassive black hole

The nearest black hole is many lightyears away.

We never have to worry about Earth being sucked in.