In space, astronauts cannot cry properly, because there is no gravity, so the tears can't flow down their faces!
175
Mars had an oxygen-rich atmosphere around 4 billion years ago
13
The population of the Earth has more than doubled since 1950.
151
Sound doesn't travel in space.
255
Astronauts get taller when they are in space.
224
The earth is .02 degrees hotter during a full moon.
157
There are 5 to 10 times more stars in the known Universe than there are grains of sand on all the world's beaches, but a single grain of sand has more atoms than there are stars in the known Universe.
20
Summer on Uranus lasts for 21 years.
358