Gravity is the attraction, or pulling force, between all matter.
Gravity is what holds everything on Earth on the ground and stops it flying off into space. It holds the Earth together, keeps the Moon orbiting the Earth, and the Earth and all the planets orbiting the Sun.
Gravity makes stars burn by squeezing their matter together.
The force of gravity is the same everywhere.
The Apollo astronauts’ steps upon the Moon were the first human experience of another space object’s gravity.
The force of gravity depends on mass (the amount of matter in an object) and distance.
The more mass an object has, and the closer it is to another object, the more strongly its gravity pulls.
Black holes have the strongest gravitational pull in the entire Universe.
The basic laws of gravity can be used for anything from detecting an invisible planet by studying the flickers in another star’s light, to helping the flight of a space probe.
Einstein’s theory of general relativity shows that gravity not only pulls on matter, but also bends space and even time itself.
Orbits are the result of a perfect balance between the force of gravity on an object (which pulls it inward towards whatever it is orbiting), and its forward momentum (which keeps it flying straight onwards).