card
067

black hole

OLogy Series
astronomy
card
067

black hole

OLogy Series
astronomy

A black hole is a collapsed star. When high-mass stars use up all their fuel, their cores collapse inward. The heaviest collapsed star cores become black holes. The pull of its gravity is so strong that nothing nearby -- dust, stars, even light -- can escape. Black holes are still one of the most mysterious objects in space.

If you fell in a star-sized black hole you would:

be pulled into a long thread

be burned to a crisp

bounce right out

Are you right?

Correct!

If you fell into a star-sized black hole, the strength of gravity would pull you apart and what was you would be stretched through space, and then crushed.

Frank Summers, astrophysicist

If all Earth shrank to the density of a black hole, it would be the size of a marble (3/4 inch across). The Sun at black hole density would be less than 4 miles across.

There is a supermassive black hole at the center of our very own galaxy, the Milky Way.

Fact
or
Fiction
?

Fact

Astronomers think they have measured stars at the center of our galaxy orbiting really fast. Only the pull of a supermassive black hole could explain such rapid movement.

Star-sized black holes are more dense than planets and stars.

Fact
or
Fiction
?

Fact

Black holes can be millions of times more dense than planets and stars. Density is a measure of how much stuff fills up a certain space.

First candidate: Cygnus X-1
When observed: early 1970s
Types: star-sized, supermassive, and mini
Quantity: dozens known, billions possible
Origin: star-sized -- where massive stars have died; supermassive -- in center of galaxies; mini -- created by the Big Bang
Significance: Gravity is so strong in a black hole that nothing can escape.

Image credits: Accretion Disk Binary System Drawing Credit, courtesy of STScI and NASA The Center of Centaurus, courtesy of E.J. Schreier (STScI) et al.,and NASA; Frank Summers: AMNH.