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
Saturn's rings are about 500,000 miles in circumference but only about a foot thick.
160
41% of the moon is not visible from earth at any time.
103
The typical spec of dust that you see floating in the air is half way in size between the Earth and a subatomic particle.
131
The population of the Earth has more than doubled since 1950.
151
Mars had an oxygen-rich atmosphere around 4 billion years ago
13