Table of Contents
Newton's Law of Gravitation
Newton's law of universal gravitation states that every mass attracts every other mass with a force proportional to the product of their masses and inversely proportional to the square of the distance between them. Published in 1687, this law explains everything from falling apples to planetary orbits.
The gravitational constant G = 6.674 × 10⁻¹¹ N·m²/kg² is one of the fundamental constants of nature. Despite being universal, gravity is the weakest of the four fundamental forces, which is why you need enormous masses (like planets) to produce noticeable gravitational effects.
Formula
Gravitational Values
| Body | Mass (kg) | Surface g (m/s²) |
|---|---|---|
| Earth | 5.972 × 10²⁴ | 9.81 |
| Moon | 7.342 × 10²² | 1.62 |
| Mars | 6.417 × 10²³ | 3.72 |
| Jupiter | 1.898 × 10²⁷ | 24.79 |
Frequently Asked Questions
Why don't we feel gravity between everyday objects?
The gravitational constant G is extremely small. Two 1 kg masses 1 meter apart attract with only 6.674 × 10⁻¹¹ N — far too weak to notice. Earth's enormous mass (6 × 10²⁴ kg) is needed to produce the 9.81 m/s² gravitational acceleration we experience daily.
Does gravity have infinite range?
Yes, gravity extends infinitely, decreasing with distance squared. However, at very large distances the force becomes negligibly small. Even light-years away, the Sun's gravity still exerts a tiny pull, which is how it gravitationally binds the Oort Cloud of comets at enormous distances.