Gravity is a force of attraction between objects that have mass. It is responsible for keeping planets in orbit around the sun and for keeping us grounded on Earth.
According to Einstein's theory of relativity, mass and energy are equivalent and can be converted into one another. This means that the energy of an object can affect its gravitational pull.
The more mass an object has, the stronger its gravitational pull will be. This is why larger objects like planets have a stronger gravitational pull than smaller objects like asteroids.
Gravity can bend and warp space-time, as described by Einstein's theory of general relativity. This means that the presence of massive objects can affect the fabric of space and time around them.
One of the biggest mysteries of gravity is how it relates to other fundamental forces, such as electromagnetism and the strong and weak nuclear forces. Scientists are also trying to understand the nature of gravity on a quantum level, which could potentially lead to a unified theory of all forces.