13. The Speed of Light: 300,00 kms per second

The speed of light is precisely 299,792,458 meters per second. A meter is defined from this constant. This discovery was one of physics' proudest accomplishments, and understanding what it really implies is one of its most interesting questions.

The speed of light is used in many different mathematical formulas and in analyzing space travel. It's part of Einstein's famous equation of relativity by which we understand the relationship of mass and energy. It's the "c" in E=mc².

12. Gravitational Constant (G): 6.67300 x 10^-11 m^3 kg^-1 s^-2

The gravitational constant appears in Newton's law of gravitation, and is known as the constant G. It also appears in Albert Einstein's theory of general relativity.

It helps to determine the force between two masses. Knowledge of G is crucial for any civil, mechanical, or aerospace engineer. Making sure that a bridge can work against both the weight of the cars pushing down on it as well as the impact of the gravitational constant's pull down is one of the more essential aspects of bridge construction.