Many, many years ago my Dad happened to get a copy of The SAS Survival Handbook out of the local library. I found it fascinating – page upon page of advice on navigation, first aid, locating and trapping food, building shelter, signalling, and everything else a body could need in the aftermath of a plane crash, earthquake or other assorted apocalypse. I spent hours poring over it, and ended up getting my own copy to spend even more hours poring over without having to worry about late fees.
There was one thing that confused me though. Among the suggested equipment that you should carry with you at all times (which included knives, razor blades and a flexible wire saw – not really so great for air travel nowdays) was something called a ‘beta-light’. This was described as a ‘crystal’ that glows – glows forever in fact – providing enough light to read a map by or to tie to a hook and line as a fishing lure.
This puzzled the hell out of me. A glowing crystal? That’s the kind of thing you’d expect to find in a Charles Berlizt book about the mystery of Atlantis, not a hard nosed book about how to snare and skin badgers. Yet there it was, listed between the iodine crystals and waterproof matches (which you should split in half lengthways to save space). “Beta-Light”. Was that a brand name? Like it’s a “better” light? I couldn’t tell. I asked my parents what this magical item might be, but they were no help and didn’t seem to comprehend how unlikely and science-fictional such an item seemed. I tried looking up “beta-light” in the encyclopedias down at the library, but there was no such entry, and those in those now far gone days before the web that was pretty much the limit of research. So the concept of perpetually glowing crystals settled down into a quiet corner of my brain to await further developments, none of which were to occur for decades.
A few weeks back Spiderman 2 was on TV. I saw Spiderman when it came out in the cinemas and quite enjoyed it, but had never actually seen the sequel, and since I had nothing on the next morning decided to stay up and watch. I thought it was pretty good – Alfred Molina in particular did a great job of making Doctor Octopus a sympathetic villain, and Toby Macquire continued to be excellent at portraying a scrawny nerd from Queens. The one thing I did find amusing about the who thing however was the plot’s insistence on the importance of tritium – a substance so common that the oceans are full of it, yet a few grams is apparently enough to destroy the whole of Manhattan. Oh how I laughed!
Just out of idle curiosity, during an ad break, I decided to look up tritium on Wikipedia. Oops. Turns out I had been confusing it with deuterium. I don’t know if a few grams of tritium would be enough to destroy Manhattan, but I wouldn’t want to risk it. Continuing through the article I stumbled over the following…
The emitted electrons from the radioactive decay of small amounts of tritium cause phosphors to glow so as to make self-powered lighting devices called betalights…
Holy crap! I clicked on the link, and there it was, all laid out for me!
Turns out a beta-light is not a “crystal”. It’s a sealed container of glass or plastic filled with gaseous tritium and lined with a phosphor. As the gas undergoes radioactive decay the beta particles emitted cause the phosphor to fluoresce, producing light. It won’t of course last forever, but it will provide light for many years, and although increasingly replaced with less radioactive light sources, it’s still pretty safe and would be a handy thing to have in a survival situation. Case closed!
In light of this surprising development, I now plan to watch Spiderman 3 to see if it can answer my questions about three body gravitational problems.
Kidding. There is no force on Earth that could make me watch Spiderman 3.