Newton's Law of Gravitation

In the late 17th century, Isaac Newton proposed one of the most important laws in all of physics: a universal law that describes the gravitational attraction between any two masses in the universe. This law unified terrestrial gravity — the force that makes an apple fall — with celestial mechanics — the force that keeps the Moon in orbit around the Earth and the planets in orbit around the Sun.

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Newton's Law of Universal Gravitation

Newton's law states that every point mass attracts every other point mass with a force that is:

• Directly proportional to the product of their masses
• Inversely proportional to the square of the distance between their centres

Mathematically:

$F = \frac{GMm}{r^2}$F=r2GMm​

where:

• F is the gravitational force between the two masses (N)
• G is the gravitational constant, 6.674 × 10⁻¹¹ N m² kg⁻² (sometimes called "big G")
• M and m are the two masses (kg)
• r is the distance between the centres of the two masses (m)