I came across this description of the size of an atom that really puts things into perspective in terms of “How small is an atom?” We all think of atoms as these little orderly nuggets but they really aren’t, but how small are they? Think about this:

“Atoms are very small. Avogadro’s Number is the number of atoms of hydrogen in one gram of the gas. Hydrogen gas isn’t the sort of thing we meet up with in everyday life, however, so to get some idea of just how small atoms are let’s think instead of a lump of carbon – coal, diamond, or soot. Because each atom of carbon weighs twelve times as much as an atom of hydrogen, the same number of atoms in a gram of hydrogen would be the same as the number of atoms in twelve grams of carbon. Twelve grams is just under one half an ounce so maybe a spoon full of sugar, a rather large diamond or a rather small lump of coal would each weigh about half an ounce. And that is how much carbon contains Avogadro’s Number of atoms, 6 X 10²³ (a 6 followed by 23 zeros) atoms. How can we put that number into perspective? Huge numbers are often called “astronomical” and many astronomical numbers are indeed big, so let’s try to find a comparably big number in astronomy.

The age of the universe, astronomers believe, is roughly 15 billion years, or 15 X 10⁹ years.  Clearly 10²³ is a lot bigger than 10⁹. Let’s turn the age of the universe into an even bigger number, using the smallest unit of time we might feel familiar with, one second. Each year contains 365 days, each day contains 24 hours, and each hour contains 3600 seconds. In rough terms each year contains 32 million seconds, about 3 X 10⁷ seconds. So 15 billion years contains 45 X 10¹⁶ seconds; following the rule that you multiply numbers like 10⁹ and 10⁷ by adding the exponents to get 10¹⁶. So again in round terms, the age of the universe is 5 X 10¹⁷ seconds old.

This is still way short of 6 X 10²³ by six powers of ten, but that doesn’t look too bad when there are 23 powers of ten to play with. But what does that mean? Well 6 orders of ten is 1 X 10⁶, or one million. This is a number we can wrap we can wrap our head around. Now imagine a supernatural being watching our universe from the moment of the Big Bang, creation. That being is equipped with one half ounce of carbon and the universes finest pair of tweezers, so fine they can pick off one atom of carbon off the lump at a time. Starting at the beginning of the universe, the Big Bang or Creation, the being removes one atom every second until right now. By now he has removed 1 x10¹⁷ atoms from the lump, or only one millionth of the atoms. It will still take our supernatural being one million more times the life of the universe to deplete the one half ounce of carbon. That’s how small atoms are.”

The above mind bender comes from the book In Search of Schrödinger’s Cat by John Gribbin, page 67-68. I thought it was cool enough to share so the next time you read about nanotech and our technology manipulating individual atoms you can truly appreciate the sizes they are talking about.