The following passage is from Kevin Kelly’s What Technology Wants.

Most hydrogen atoms were born at the beginning of time. They are as old as time itself. They were created in the fires of the big bang and dispersed into the universe as a uniform warm mist. Thereafter, each atom has been on a lonely journey. When a hydrogen atom drifts in the unconsciousness of deep space, hundreds of kilometers from another atom, it is hardly much more active than the vacuum surrounding it. Time is meaningless without change, and in the vast reaches of space that fill 99.99 percent of the universe, there is little change.

After billions of years, a hydrogen atom might be swept up by the currents of gravity radiating from a congealing galaxy. With the dimmest hint of time and change it slowly drifts in a steady direction toward other stuff. Another billion years later it bumps into the first bit of matter it has ever encountered, After millions of years it meets the second. In time it meets another of its kind, a hydrogen atom. They drift together in mild attraction until aeons later they meet an oxygen atom. Suddenly something weird happens. In a flash of heat they clump together as one later molecule. Maybe they get sucked into the atmosphere circulation of a planet. Under this marriage, they are caught in great cycles of change. Rapidly the molecule is carried up and then rained down into a crowded pool of other jostling atoms. In the company of uncountable numbers of other water molecules it travels this circuit around and around for millions of years, from crammed pools to expansive clouds and back. One day, in a stroke of luck, the water molecule is captured by a chain of unusually active carbons in one pool. Its path is once again accelerated. It spins around in a simple loop, assisting the travel of carbon chains. It enjoys speed, movement, and change such as would not be possible in the comatose recesses of space. The carbon chain is stolen by another chain and reassembled many times until the hydrogen finds itself in a cell constantly rearranging its relations and bonds with other molecules. Now it hardly ever stops changing, never stops interacting.