The Plunge Crash Course

Look before you leap. Before you decide to throw yourself into the ultimate abyss, we feel you should know a few facts about black holes to improve your experience. Please take a moment and read over this: 

The phrase "black hole" was coined by American John Wheeler in 1968 to describe an object with a gravitational force so powerful that not even light could escape its pull. The idea of black holes goes back over 200 years ago. British astronomer John Mitchell calculated that a star 500 times larger than the sun would have enough gravity to prevent light from escaping. Mitchell figured this out using Newton's theories of gravity and corpuscular light (light is made up of tiny corpuscules).

(Learn more about the history of black holes in the Discovery Section)

Today we have a different idea of both gravity and light because of Albert Einstein's Theory of Relativity. 

New black hole theory is based on these concepts:

The mass of any object curves space and time. The more massive an object is, the more it curves the space and time around it.

Gravity is a result of curved space and time. So, the more massive an object is, the more gravity it has.

Light is made up of photons which act like both a wave and a particle (dual nature).

Light has no resting mass or weight so nothing can travel faster than light.

The speed of light is constant (never changes) and travels in vacuo (empty space) at: 

186,000 miles or 300,000 km per second.

Light is affected by gravity because it has momentum and energy.

A black hole is an object that has been crushed into a single point (known as a singularity) with infinite density (it has no height, width or depth)  that space and time as we know it stops. The speed necessary to escape the gravity is greater than light. Light will never be able to reflect or travel back out of the hole.

How do black holes form in nature?

Stars come in many sizes. Black holes form when a star with enough mass runs out of fuel. Stars burn hydrogen gas in a process known as fusion, which combines two lighter atoms to form a heavier atom. Fusion releases heat energy (outward pressure) which keeps a star's gravity from crushing it (inward pressure). A star runs out of fuel when fusion uses more energy than it releases. When there is no heat energy to resist the gravity, the star collapses which releases enormous amounts of energy. If the star is larger than 8 suns, it blows off its top layers in a huge explosion known as a supernova. What's left is known as a collapsed star or a stellar remnant. 

If the collapsed star has...

• less mass than 1.4 suns, the star is held up because the electrons in the star's atoms repel other electrons causing outward pressure known as electron degeneracy. The star becomes a white dwarf.
• more mass than 1.4 suns, gravity pushes the electrons into the atomic nuclei. When negative charged electrons and positive charged protons meet, they cancel each other out and form neutrons. The star is supported as neutrons repel neutrons and it becomes a neutron star.
• more mass than 2 or 3 suns, gravity overpowers both electron and neutron resistance causing gravity to pull the entire star into itself to form a black hole.

If the star was a perfect sphere with no spin, it would collapse into a Schwarzschild black hole. Space would lead directly into the black hole. The only property of this type of black hole is its mass.

If the star was a rotating as all stars do in nature, it would collapse into a Kerr black hole. Space would twist in a spiral into the black hole. The only properties of this type of black hole are its mass and angular momentum (speed of its spin).

(Learn about Schwarzschild and Kerr black holes in the Types Section)

One common misunderstanding about black holes is that if you go into a black hole you will end up in a new universe, back in time or out of some wormhole as you may have seen in many science fiction movies.

Truth is, your particles may end up in another dimension, but you won't, because by then you would have been ripped apart limb from limb by the black hole's tidal wave gravity and crushed into something much, much smaller than tip of a needle.

(Learn about other misunderstandings in the Myths Section)

Now that you are eager to boldly go into a black hole, let's not wait another second.