... universe(Hawking 116). But what exactly is a black hole? A black hole is baisicly thought to be the last evolutionary stage of massive stars-at least fifteen times as massive as the Sun. Astronomers believe that a black hole forms when a massive star runs out of nuclear fuel and ... and found that black holes are not completely black. He discovered that they send out radiation particles at a steady rate. He found that the uncertainty principle, which says that particles cannot have both a well-defined position of a particle and a well-defined velocity, allows particles to travel ... for...

• Word Count: 905
• Approx Pages: 4
• Has Bibliography
• Grade Level: High School