How is matter "tuned for life?"
Short answer:
If the charges, sizes and distances of the subatomic particles were even slightly different the universe could have been created in exactly the same way but would be devoid of life.
Long answer:
"There is good reason to believe that we are in a universe permeated with life, in which life arises, given enough time, wherever the conditions exist that make it possible. How many such places are there? Arthur Eddington, the great British physicist, gave us a formula: one hundred billion stars make a galaxy, and one hundred billion galaxies make a universe. The lowest estimate I have ever seen of the fraction of them that might possess a planet that could support life is one percent. That means one billion such places in our home galaxy, the Milky Way; and with about one billion such galaxies within reach of our telescopes, the already observed universe should contain at least one billion billion -- 10^18 -- places that can support life.
So we can take this to be a universe that breeds life; and yet, were any one of a considerable number of physical properties of our universe other than it is -- some of those properties basic, others seeming trivial, almost accidental -- that life, that now appears to be so prevalent, would become impossible, here or anywhere....
...I should like now to raise two problems to do with protons and electrons, one involving their masses, the other their electric charge.
Every atom has a nucleus composed of protons and neutrons, except the smallest one, hydrogen, which has only one proton as its nucleus. Electrons orbit these nuclei at distances relatively greater than separate our sun from its planets. Both protons and neutrons have masses almost two thousand times the mass of an electron -- 1840 times when I last looked -- so virtually the whole mass of an atom is in its nucleus. Hence the atom is hardly disturbed at all by the motions of its electrons, and an atom can hold its position in a molecule, and molecules their positions in larger structures. Only that circumstance permits molecules to hold their shapes, and solids to exist.
If on the contrary the protons and neutrons were closer in mass to the electrons, whether light or heavy, then the motions of the electrons would be reflected in reciprocal motions by the others. All structures composed of such atoms would be fluid; in such a universe nothing would stay put. There could not be the fitting together of molecular shapes that permits not only crystals to form, but living organisms.
And now, electric charge: How does it come about that elementary particles so altogether different otherwise as the proton and electron possess the same numerical charge? How is it that the proton is exactly as plus-charged as the electron is minus-charged?
It may help to accept this as a legitimate scientific question to know that in 1959 two of our most distinguished astrophysicists, Lyttleton and Bondi, proposed that in fact the proton and electron differ in charge by the almost infinitesimal amount, 2 x 10 -18
e -- two billion billionths
e, in which
e is the already tiny charge on either the proton or electron. The reason they made that proposal is that, given that nearly infinitesimal difference in charge, all the matter in the universe would be charged, and in the same sense, plus or minus. Since like charges repel one another, all the matter in the universe would repel all the other matter, and so the universe would expand, just as it is believed to do. The trouble with that idea is that yes, the universe would expand, but -- short of extraordinary special dispensations - it would not do anything else. Even so small a difference in electric charge would be enough to overwhelm the forces of gravitation that bring matter together; and so we should have no planets, no stars, no galaxies -- and, worst of all, no physicists.
No need to worry, however. Shortly after Lyttleton and Bondi’s proposal, John King and his group at the Massachusetts Institute of Technology began to test experimentally whether the proton and electron differ in charge, and found that the charges appear to be wholly identical. That is an extraordinary fact, and not made easier to understand by the present belief that, though the electron is a single, apparently indivisible particle, the proton is made up of three quarks, to of them with charges of +2/3
e, and one with a charge of -1/3
e.
To summarize, if the proton and neutron did not have enormously greater mass than the electron, all matter would be fluid; and if the proton and electron did not possess exactly the same electric charge, no matter would aggregate. These are primary conditions for the existence of life in the universe..."
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