Monday, February 4, 2013

Billion Year Old Carbon

On the second floor of the Natural History Museum of London, at the end of the gallery containing their extensive scientific collection of minerals, in a room called only “The Vault”, against the back wall, are displayed a series of meteorites. One of them, the Cold Bokkeveld carbonaceous chondrite from South Africa, is accompanied by a small glass vial, thinner than your little finger. And at the bottom of that vial is an almost indistinguishable white smudge, that if your attention was not called to it, you might mistake for a fingerprint. But a quick reading of the accompanying label will stop you in your tracks. The material in that vial was obtained by vaporizing a small sample of the rock, and contains microscopic diamonds created in the interstellar void by the pressure of a supernova explosion, then transported to earth by the meteorite. Their unique istopic xenon ratios hint at an origin that predates our entire solar system, making them, in the words of the museum, quite simply “the oldest things you will ever see”. They are, literally, stardust on Earth, the “billion year old carbon” alluded to by Joni Mitchell, and possibly the most humbling item in the museum’s entire collection given their size. I, personally, found myself rooted to the spot for several full minutes. As a geologist, I have seen examples of the Jack Hills zircons from Australia, the oldest material on earth, and I have found ways to think at scales that far exceed my own experience. But here was something that physically pushed those boundaries even further in both space and time, and I struggled with that comprehension all afternoon as I made my way back past the Jurassic fish skeletons and centuries-old tree rings that now seemed almost trivial, back out to the bustle of human existence that now, even more than ever, I am forced to recognize represents no more than an eyeblink and a mote in our larger understanding of the universe. I highly recommend the experience to anyone. References and connections: