Chapter 1 A GREAT SPACE MYSTERY Black holes are a mystery of outer space People can see stars planets and other objects in the sky But black holes are invisible We cannot see them This artwork shows what a black hole might look like if we could see it Can you find the black hole 4
Astronomers study outer space These scientists can look at planets and stars But they can’t look at black holes That’s why black holes are such mysteries An astronomer adjusts a giant telescope Astronomers use telescopes to study outer space 5
Gravity makes this parachuter fall back to Earth What Is a Black Hole A black hole isn’t really a hole It is an area in space with very strong gravity Gravity is a force that pulls objects together Earth’s gravity keeps us from floating away We can jump off the ground But Earth’s gravity pulls us back down 6
A black hole’s gravity is much stronger than Earth’s Its gravity is stronger than anything in the universe The universe is all of outer space An artist created this picture of a black hole The black hole is surrounded by stars dust and gas 7
