Guide Note

Gravity is a physical force that will attract two objects of mass toward each other. On Earth, it is the force that pulls all objects towards the surface of the planet. It also creates the sensation of weight. In interstellar space, it is observed as the force which keeps objects in orbit around one another.

Fast Facts

1. Also known as: Gravitation
2. Responsible for keeping objects on Earth's surface
3. Responsible for the orbit of the planets
4. Observed force is stronger on planets with more mass
5. Acceleration due to gravity on Earth is 9.8 m/s²
6. Heavier objects will not accelerate faster than lighter objects
7. First scientifically established by Sir Isaac Newton in 1665¹
8. Albert Einstein established a more complex gravitational model in 1915
9. Einstein's model does not contradict the Newtonian model¹

Sir Isaac Newton's observations about gravity culminated in a simple relationship known as Newton's Law:

• The gravitational force between two objects is directly proportional to their masses

Represented mathematically:

• Force_Gravity = (Mass₁ * Mass₂) / (Distance²)