 An infinite distance: stars in the sky

## Why do we use exponents?

Some numbers are so big that it’s hard to write them in the regular way.

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Like 1,000,000,000,000,000. It would be hard to count all those zeroes, so instead we just write down how many zeroes there are. That’s easier and faster to read – if you know how.

## How do you read exponents?

A 1 with one zero next to it means 1 multiplied by 10, or ten. A 1 with two zeros next to it means 1 x 100, or in exponents 102, or a hundred. And a 1 with three zeros next to it means 1 x 1000, or 103, or a thousand. Ten is ten times bigger than one, and a hundred is ten times bigger than ten, and a thousand is ten times bigger than a hundred.

## For larger numbers, the sequence goes like this:

• 10,000 = 104 = ten thousand
• 100,000 = 105 = a hundred thousand
• 1,000,000 = 106 = a million
• 10,000,000 = 107 = ten million
• 100,000,000 = 108 = a hundred million
• 1,000,000,000 = 109 = a billion
• 1,000,000,000,000 = 1012 = a trillion
• 1,000,000,000,000,000 = 1015 = a quadrillion

## Googol and Googolplex

The biggest numbers anyone has named are a googol, which is one with a hundred zeros after it (10100) and a googolplex, which is one with a googol zeros after it (10googol). A googol is so big that it is more than the number of atoms in the universe as far as we can see with telescopes (about 1080).

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A googolplex would be a lot more than that – there’s no real number of things that comes anywhere near a googolplex. But those aren’t the biggest possible numbers, because you could always say, “a googolplex plus one, a googolplex plus two,” and so on. Numbers are infinite, so you never come to the end of them.