Why is the sky blue?
What is lightning?
What are the states of matter?
Does hot water freeze faster than cold?
Why does a can of Coke sink while a can of Diet Coke floats?
Why do you close your eyes when you sneeze?
Why do mosquitoes bite me more than my friends?
Why do your feet stink?
How does gravity work?
How fast does the space shuttle move in orbit?
What is escape velocity?
What would happen if you turned on your headlights while moving at the speed of light?
You remember the fantasy: If you could jump high enough, you could leave Earth and bound up to the moon. To pull off that colossal kangaroo act, you'd have to reach escape velocity -- the minimum velocity needed to permanently escape the gravity of a planet or star.
Escape velocity is even simpler to calculate than orbital velocity. In general, all you need to know are the gravitational constant ("G"), the mass of the planet or star, and the distance of the spaceship from the center of mass of the planet or star.
(Need information on units?)
We had an encyclopedia do the math for us, and learned that escape velocity at Earth's surface is 11,200 meters per second. Just as with orbital velocity, the further from Earth, the lower the escape velocity.
