Mars had an oxygen-rich atmosphere around 4 billion years ago
13
A comet's tail always points away from the sun.
2
Jupiter is bigger than all the other planets combined.
254
The earth travels through space at 660,000 miles per hour.
189
There are approximately 3,500 astronomers in the U.S. - but over 15,000 astrologers.
124
Pluto is smaller than Russia.
9
The Earth gets heavier each day by tons, as meteoric dust settles on it.
118
