Lengths From Very Small to Very Large

Our Universe has very small things (like atoms), and very large things (like galaxies).

And this is where metric prefixes like milli- and kilo- can be very useful.

Example: the distance between London and New York is about 5,580,000 meters.

But it is easier to use 5,580 kilometers.

Here is an illustration of sizes, from the very small (a Quark) to the very large (the known Universe):

length continuum

The sizes are in meters using metric numbers.
(Just add the word "meter" after them, so we get "millimeter", "terameter", etc.)


A Quark is about a femtometer in size.

Cells are about a micrometer in size (many different sizes though!)

The Milky Way is about a zettameter in size.

The Numbers

The numbers (like 106) use Scientific Notation to show how big the value is.

Example: 106 means to use 10 in a multiplication 6 times:

10 × 10 × 10 × 10 × 10 × 10 = 1,000,000

But in practice it is easier to think "a 1 followed by 6 zeros"

Which is a million.

The prefix is mega-, so a megameter is a million meters.

Example: 109 is a 1 followed by 9 zeros: 1,000,000,000 (a billion).

The prefix is giga-, so a gigameter is a billion meters.

Example: 10-9 is a 1 moved nine places the other side of the decimal: 0.000 000 001

It is also called a billionth.

The prefix is nano-, so a nanometer is a billionth of a meter.

Looking at the illustration we can see that a person is about 1 meter in size, a mountain is about 103 (one thousand) meters in size, and the diameter of the Sun is about 109 (one billion) meters.

Example: We could also say the Sun is about a "gigameter" in size

It's diameter is actually 1.392×109 meters, or 1.392 gigameters, or simply 1.392 Gm

Some Interesting Facts: