# The Universe By Numbers

 Exponential or Scientific Notation: It is easier to write very large numbers such as 100,000,000 as 108 (“1” followed by 8 “0”s). Similarly very small numbers are written using negative exponents, e.g. 0.0000001 is 10-7 (the “1” is seven places to the right of the decimal point). Bear in mind though that 109 is ten times the size of 108, and 1018 is ten billion times larger.

Some of the numbers, both small and large, that are bandied around in modern physics are very difficult to grasp. Below is a table listing - from the infinitesimally small to the incomprehensibly large - some of the numbers which are relevant to the subject matter.

Obviously, the units used affects these numbers (e.g. meters, kilometers, miles, light years, etc), but I have tried to use consistent metric units throughout: meters for distance, seconds for time, meters/second for speed, degrees Kelvin for temperature, kilograms for mass, kilograms/meter3 for density, Joules for energy, Coulombs for electrical charge, kilopascals for pressure.

 The Scale of the Universe: Cary Huang has created an excellent interactive graphical representation of the scale of the universe, from strings to the edge of the observable universe.
The different types of measurements are also color-coded for convenience: