Gravity

What is Gravity?

Gravity is described by the general theory of relativity (proposed by Albert Einstein in 1915). Describing gravity as a consequence of the curvature of spacetime caused by the uneven distribution of mass/energy rather than describing it as a force.

Here are some facts about gravity that explain how it relates to life on Earth and other objects in our solar system.

• What is gravity? Objects with mass that are attracted to each other.

• Gravity keeps Earth and the other planets in our solar system in orbit around the Sun. It also keeps the Moon in orbit around Earth which is crucial to our planet and our lives!

• The tides are caused by the rotation of the Earth and the gravitational effects of the Moon and Sun.

• Because Mars has a lower gravity than Earth, a person weighing 200 pounds on Earth would only weigh 76 pounds on Mars.

• It is thought that Isaac Newton’s theories on gravity were inspired by seeing an apple fall from a tree.

• While Newton’s older law of universal gravitation is accurate in most scenarios, modern physics uses Albert Einstein's general theory of relativity to describe gravity.

• The force of gravity 100 kilometres (62 miles) above Earth is just 3% less than at the Earth’s surface.

I'd also like to talk about how gravity works. Waves of gravity are ripples in spacetime. First we need to know what spacetime is and here is a video that explains spacetime and what gravity is: