Tuesday, April 15, 2008

Inside Nature's Time Capsule

I couldn’t resist a science news story that’s so reminiscent of Jurassic Park. Amber is the closest thing to a natural time capsule I can think of. It’s almost a time machine. The stuff preserves bugs, leaves, feathers, and who knows what else almost perfectly for millions of years. Researchers recently found a few hundred new species of fossilized animals that had been trapped in amber since the Mesozoic Era. And, with a 3D printer, they can make complete models of the fossilized creatures.

The mosquito-containing amber atop John Hammond’s cane in Jurassic Park was transparent – giving a lovely little image of the bug trapped inside. But a large percentage of amber turns opaque as it solidifies, so it’s impossible to see the animals trapped inside it. Bring on the physics! To look inside these bits of amber, the paleontologists are using a technique known as propagation phase contrast microradiography (phew!).

Physicists have found that if you want to look inside something that visible light won’t pass through (like granite or opaque amber), you could always try looking through it with a different kind of light. In this case, the amber is penetrated with X-rays created by a synchrotron.

A synchrotron is a particle accelerator that uses both electric and magnetic fields to gradually accelerate particles around a circular track. To be accelerated, the particles must be charged; but charged particles that accelerate emit light (a property that is present in many facets of your everyday life). Electrons in a synchrotron can be accelerated so that they emit steady streams of X-rays. The X-rays penetrate the amber and give an image of what lies inside.

In a second study, the researchers found prehistoric feathers that may have belonged to a dinosaur (ok, they can't prove that...yet...but it is a legitimate theory!).

The process is still relatively slow. It takes about four days to analyze ten kilograms of amber. Developments are being made to increase that amount by ten. Because so much of fossilized amber is opaque, the scientists are eager to start looking at the history stuck inside.

Above: Chunks o' amber




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