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08/01/2012
Unexpected Stuff
CHAPTER 24 - Photons and Positrons
All is forgiven. After the embarrassment of one of the teams of the Large Hadron Collider erroneously claiming that neutrinos travel faster than the speed of light, the guys and gals working on the primary objective of the LHC, finding the Higgs boson, came through with flying colors. Some scientists here in New Jersey were among the thousands involved in this project. Our newspaper, the Star-Ledger, mentioned groups at Rutgers and Princeton celebrating the finding. The question now is how does the Nobel committee decide who will get the Nobel Prize for this monumental achievement? Obviously, Peter Higgs himself should be in the running but there were others who contributed significantly to the theory of the Higgs. One of those individuals is Abdus Salam, already a Nobel Prize winner. In an earlier column on my experiences in Sicily, I mentioned that Salam was present at a memorable anniversary ceremony that I attended. I would think that Higgs would be a sentimental favorite, having lived long enough to actually be present when the discovery of a boson likely to be the Higgs, or a Higgs, boson was announced.
This past month or so I've been devoting most of my time to a much more familiar boson, the photon. Whereas the Higgs boson and its associated field are apparently the source of mass, the photon has no mass and hence is more suitable for a lightweight such as myself to tackle. The reason for my concern with photons is that I was preparing a talk for the Old Guard group to which I belong; the subject of the talk was "Let There be Light". I talked about the light coming from the Big Bang, and a bit about Newton and others who contributed to elucidating the nature of light, with most of the emphasis being on light-emitting diodes (LEDs).
The talk was my first attempt at a PowerPoint presentation, as well as my first talk in which I finally joined the digital age, putting all my slides on one of these tiny thumb drives. Being a complete neophyte at both these procedures, it was a major effort for this 84-year-old guy. Ironically, for a talk titled "Let There Be Light", there almost wasn't any light. Our visual aid expert in the Old Guard set up the computer and projector to accommodate my thumb drive? He flashed my first slide on the screen and the projector lamp promptly expires! There was no light and no replacement bulb! Fortunately, our meetings are held in the town of New Providence Municipal Center and Dave, our visual guy, managed to find another projector in the building and I had my light!
My subject, light and LEDs, contrasted with the subject of our Old Guard speaker the week before. Dr. Philip Eisner talked on global warming and did an excellent job of laying out the gloomy outlook for our future and our failure to seriously address the problem. If anything, it's beginning to look as though climate scientists have been underestimating the seriousness of the problem. Eisner showed projections of expected drought conditions worldwide in the relatively near future that pose a horrific threat to mankind with huge problems anticipated when hungry masses try to move to areas where food is available. That's just one example of what's in store.
Meanwhile, our politicians blithely ignore the situation, even to the point of the North Carolina Senate voting overwhelmingly for a bill legislating how future sea levels rises may be calculated! The bill mandates that any calculations of future sea level changes be restricted to a linear model. This completely ignores the fact that scientists are finding that the rise in sea level is actually accelerating, not rising linearly! Indeed, NASA has just reported that its satellites have seen a very unusual amount of surface melting of the ice surfaces in Greenland. Whereas about half of the ice surface melts in the summer normally, in mid July this year some 97 percent of the surface ice melted at some point. NASA workers were apparently so shocked by the finding that they at first questioned whether the data were real!
In my Old Guard talk I showed a slide of the electromagnetic spectrum, which covers the range from long wavelength radio waves to ultra-short wavelength, highly energetic gamma rays. I pointed out that every warm body emits photons, including ourselves. Our photons are in the infrared range and are the reason we can be spotted by infrared cameras. On the other hand, the most energetic photons are those gamma rays, most closely associated with events such as exploding stars, black holes sucking in stars or other humongous astronomical happenings. One doesn't expect to find gamma rays originating from natural sources here on Earth.
However, in the August issue of Scientific American there's a fascinating article by Joseph Dwyer and David Smith about just that happening. Much to everyone's surprise, orbiting satellites sent into space to study the sources of gamma rays in the deep reaches of the universe began detecting gamma rays emanating from down below the satellites, from Earth itself! After many years of study, it turns out that the sources of these gamma rays are thunderstorms. In recent weeks, many areas around us here in the Northeast have suffered severe damage from intense thunderstorms. One just wreaked havoc here in New Jersey last week in the town of Freehold.
I certainly didn't imagine that gamma rays are emitted in these storms. I was intrigued by a comment in the Scientific American article about what would happen if an airplane was caught in a thunderstorm emitting gamma rays and high energy electrons. The crew and passengers could receive a lifetime's worth of radiation from natural sources in that thunderstorm! Of course, pilots don't normally fly into thunderstorms, which aren't great places for a plane anyway.
Another surprise is that antimatter in the form of positrons, the antimatter version of electrons, is also formed in lightning strikes, Antimatter is not something expected from natural sources these days. After the Big Bang there were presumably equal amounts of matter and antimatter in the universe. I'm not sure whether the theoretical physicists have pinned down for sure why the ordinary matter of which we're composed prevailed over the antimatter. At any rate we're here. Getting back to those positrons, in lightning strikes in which the electrons flow from the ground up, the positrons, being positively charged, flow down to the ground. They won't stick around very long, combining with ordinary electrons or being annihilated in collisions with ordinary stuff. However, either electrons or positrons formed in lightning discharges can apparently be caught up in magnetic lines of force and carried halfway around the world from the lightning flash from which they formed.
Normally, at this point I would continue with my memoirs but this month I'm cutting the column short. Aside from the work I put into preparing my talk, something much more important and time consuming occurred this past month. My wife had major surgery earlier in July. Thankfully, all seems to be going well but with all the hospital and rehabilitation stays and the follow-up rehab and medical matters, as well as the care giving duties, I'm going to take a nap!
Next column will be posted, hopefully, on or about September 1.
Allen F. Bortrum
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