Mars had an oxygen-rich atmosphere around 4 billion years ago
13
A 100-pound person on Earth would weigh 38 pounds on Mars.
102
Sound doesn't travel in space.
255
Today's top fuel dragsters take off with more force than the space shuttle.
120
More than 20 million meteoroids enter Earth's atmosphere every day.
139
There are approximately 3,500 astronomers in the U.S. - but over 15,000 astrologers.
124
A neutron star (what remains after a Super Nova) is so dense that a portion of it the size of a sugar cube would weigh as much as all of humanity, or more than all the cars in the United States.
5