# Gravitational Constant

21.06.2015

6.67384(80) × 10-11 m3 kg-1 s-2

Episode #7 of the course “Most important numbers in the world”

Gravity is a complex concept that continues to elude scientists in all its subtleties. Since its discovery and the beginnings of theories surrounding the properties and mechanisms of gravity, Newton and others have used a standard measurement known as “G” (or affectionately called “Big G”) to represent the force of gravity as a constant.

According to the law of universal gravitation, the force between two bodies depends on their size and their relative distance to one another. The number represented by G is equal to the proportional constant that is exerted between these two bodies, and is called the “gravitational constant.” Newton’s Gravitational Constant is expressed as:

F = Gm1m/ r2

where “F” is the force, “m1” and “m2” represent the larger and smaller masses being measured in relation to one another, and “r” is the distance between those masses.

Mathematically, the representation of G is expressed in a series of units (time squared, length cubed divided by mass, etc) that are necessary to cancel and compute all the aspects of the units of measurement in the various equations.

In addition to its importance in understanding how particles of matter relate to one another on Earth, the concept of G is especially important for understanding the properties and functions of matter in space. Astrophysics could not have expanded in the directions and understandings that allowed the space exploration and atomic energy technologies of the 20th century if it had not been for the enhanced understanding of the constant measurement of the force of gravity.

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