Intuitive mathematicians often burn out young. Not Dirac! - he is a Michelangelo who started very young, never stopped, is still going strong. Antimatter is not necessarily his contribution most esteemed by colleagues, but his other major ones are so abstruse as to defy putting them into common words:
A mathematical attribute of particles dubbed "spin"; co invention of the Fermi - Dirac statistics; an abstract mathematical replacement for the "pellucid ether" of classical mechanics. For centuries, ether was used and its "physical reality" generally accepted either as "axiomatic" or "proved" through various negative proofs. Both "axiom" and "negative proof" are treacherous; the 1887 Michelson - Morley experiment showed no physical reality behind the concept of ether, and many variations of that experiment over many years gave the same null results.
So Einstein omitted ether from his treatments of relativity - while less brilliant men ignored the observed facts and clung to classical ether for at least 40 years.
Dirac's ether (circa 1950) is solely abstract mathematics, more useful thereby than classical ether as it avoids the paradoxes of the earlier concepts. Dirac has consistently warned against treating mathematical equations as if they were pictures of something that could be visualized in the way one may visualize the Taj Mahal or a loaf of bread; his equations are rules concerning space - time events - not pictures.
(This may be the key to his extraordinary successes.) One more example must represent a long list:
Dirac's work on Georges Lemaltre's "primeval egg" - later popularized as the "big bang."
Honors also are too many to list in fulclass="underline" fellow of the Royal Society, its Royal Medal, its Copley Medal, honorary degrees (always refused), foreign associate of the American Academy of Sciences, Oppenheimer Memorial Prize, and (most valued by Dirac) Great Britain's Order of Merit.
Dirac "retired" by accepting a research professorship at Florida State University, where he is now working on gravitation theory. In 1937 he had theorized that Newton's "constant of gravitation" was in fact a decreasing variable ... but the amount of decrease he predicted was so small that it could not be verified in 1937.
Today the decrease can be measured. In July 1974 Thomas C. Van Flandern of the U.S. Naval Observatory reported measurements showing a decrease in gravitation of about a ten - billionth each year (1 per 1010 per annum). This amount seems trivial, but it j very large in astronomical and geological time. If these findings are confirmed and if they continue to support Dirac's mathematical theory, he will have upset physical science even more than he did in 1928 and 1930.
Here is an incomplete list of the sciences that would undergo radical revision: physics from micro - through astro - , astronomy, geology, paleontology, meteorology, chemistry, cosmology, cosmogony, geogony, ballistics. It is too early to speculate about effects on the life sciences, but we exist inside this physical world and gravitation is the most pervasive feature of our world.
Theory of biological evolution would certainly be affected. It is possible that understanding gravitation could result in changes in engineering technology too sweeping easily to be imagined.
Antimatter and You
Of cosmologies there is no end; astrophysicists enjoy "playing God." It's safe fun, too, as the questions are so sweeping, the data so confusing, that any cosmology is hard to prove or disprove. But since 1932 antimatter has been a necessary datum. Many cosmologists feel that the universe (universes?) has as much antimatter as matter - but they disagree over how to balance the two.
Some think that, on the average, every other star in our Milky Way galaxy is antimatter. Others find that setup dangerously crowded - make it every second galaxy. Still others prefer universe - and - anti universe with antimatter in ours only on rare occasions when energetic particles collide so violently that some of the energy forms antiparticles. And some like higher numbers of universes - even an unlimited number.
One advantage of light's finite speed is that we can see several eons of the universe in action, rather than just one frame of a very long moving picture. Today's instruments reach not only far out into space but also far back into time; this permits us to test in some degree a proposed cosmology. The LST (Large Space Telescope), to be placed in orbit by the Space Shuttle in 1983, will have 20 times the resolving power of the best ground - based and atmosphere - distorted conventional telescope - therefore 20 times the reach, or more than enough to see clear back to the "beginning" by one cosmology, the "big bang."
(Q: What happened before the beginning? A: You tell me.)
When we double that reach - someday we will - what will we see? Empty space? Or the backs of our necks?
(Q: What's this to me? A: Patience one moment....)
The star nearest ours is a triplet system; one of the three resembles our sun and may have an Earthlike planet - an inviting target for our first attempt to cross interstellar space. Suppose that system is antimatter - BANG! Scratch one starship.
(Hooray for Zero Population Growth! To hell with space - travel boondoggles!)
Then consider this: June 30, 1908, a meteor struck Siberia, so blindingly bright in broad daylight that people 1,000 miles away saw it. Its roar was "deafening" at 500 miles. Its ground quake brought a train to emergency stop 400 miles from impact. North of Vanavara its air blast killed a herd of 1,500 reindeer.
Trouble and war and revolution - investigation waited 19 years. But still devastated were many hundreds of square miles. How giant trees lay pinpointed impact.
A meteor from inside our Galaxy can strike Earth at 50 miles/second.
But could one hit us from outside our Galaxy?
Yes! The only unlikely (but not impossible) routes are those plowing edgewise or nearly so through the Milky Way; most of the sky is an open road - step outside tonight and look. An antimeteor from an antigalaxy could sneak in through hard vacuum - losing an antiatom whenever it encountered a random atom but nevertheless could strike us massing, say, one pound.
One pound of antimatter at any speed or none would raise as much hell as 28,000 tons of matter striking at 50 miles/second.
Today no one knows how to amass even a gram of antimatter or how to handle and control it either for power or for weaponry. Experts assert that all three are impossible.
However...
Two relevant examples of "expert" predictions:
Robert A. Millikan, Nobel laureate in physics and distinguished second to none by a half - century of re search into charges and properties of atomic particles, in quantum mechanics, and in several other areas, predicted that all the power that could ever be extracted from atoms would no more than blow the whistle on a peanut vendor's cart. (In fairness I must add that most of his colleagues agreed - and the same is true of the next example.)
Forest Ray Moulton, for many years top astronomer of the University of Chicago and foremost authority in ballistics, stated in print (1935) that there was "not the slightest possibility of such a journey" as the one the whole world watched 34 years later: Apollo 11 to the moon.
In 1938, when there was not a pinch of pure uranium - 235 anywhere on Earth and no technology to amass or control it, Lise Meitner devised mathematics that pointed straight to atom bombs. Less than seven years after she did this, the first one blazed "like a thousand suns."
No possible way to amass antimatter?
Or ever to handle it?
Being smugly certain of that (but mistaken) could mean to you ... and me and everyone
The END
AFTERWORD
I am precluded from revising this article because Encyclopaedia Britannica owns the copyright; I wrote it under contract. But in truth it needs no revision but can use some late news flashes.