WHILE EINSTEIN AND Hubble were productively unraveling the large-scale structure ofthe os, others were struggling to uand something closer to hand but in its way justas remote: the tiny and ever- mysterious atom.
The great Caltech physicist Richard Feynman once observed that if you had to reducestific history to one important statement it would be 「All things are made of atoms.」 Theyare everywhere and they stitute every thing. Look around you. It is all atoms. Not just thesolid things like walls and tables and sofas, but the air iween. And they are there inhat you really ot ceive.
The basic w arra of atoms is the molecule (from the Latin for 「little mass」).
A molecule is simply two or more atoms w together in a more or less stablearra: add two atoms of hydrogen to one of oxygen and you have a molecule of water.
Chemists tend to think in terms of molecules rather thas in much the way thatwriters tend to think in terms of words and not letters, so it is molecules they t, and theseare numerous to say the least. At sea level, at a temperature of 32 degrees Fahre, onecubitimeter of air (that is, a space about the size of a sugar cube) will tain 45 billionbillion molecules. And they are in every single cubitimeter you see around you. Thinkhow many cubitimeters there are in the world outside your window—how many sugarcubes it would take to fill that view. Then think how many it would take to build a universe.
Atoms, in short, are very abundant.
They are also fantastically durable. Because they are so long lived, atoms really get around.
Every atom you possess has almost certainly passed through several stars and been part ofmillions anisms on its way to being you. We are each so atomically numerous andso vigorously recycled at death that a signifit number of our atoms—up to a billion foreach of us, it has been suggested—probably once beloo Shakespeare. A billion moreeach came from Buddha and Genghis Khan ahoven, and any other historical figureyou care to he personages have to be historical, apparently, as it takes the atomssome decades to bee thhly redistributed; however muay wish it, you arenot yet oh Elvis Presley.)So we are all reinations—though short-lived ones. When we die our atoms willdisassemble and move off to find new uses elsewhere—as part of a leaf or other human beingor drop of dew. Atoms, however, go on practically forever. Nobody actually knows how longan atom survive, but acc to Marti is probably about 1035years—a numberso big that even I am happy to express it in notation.
Above all, atoms are tiiny indeed. Half a million of them lined up shoulder toshoulder could hide behind a human hair. On such a scale an individual atom is essentiallyimpossible to imagine, but we of course try.
Start with a millimeter, which is a lihis long: -. Now imagihat line divided into athousand equal widths. Each of those widths is a mi. This is the scale of micranisms.
A typical paramecium, for instance, is about two mis wide, 0.002 millimeters, which isreally very small. If you wao see with your naked eye a paramecium swimming in adrop of water, you would have to enlarge the drop until it was some forty feet across.
However, if you wao see the atoms in the same drop, you would have to make the dropfifteen miles across.
Atoms, in other words, exist on a scale of minuteness of another order altogether. To getdown to the scale of atoms, you would o take eae of those mi slic