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06/22/2012 07:00:00

Notes from the Back Row: "The Isotope Time Machine"

Were dinosaurs slow and stupid, as used to be the prevailing wisdom, or nimble and smart enough to eat an attorney, as in the 1993 film Jurassic Park? The answer depends largely on whether the T. Rex in question is cold blooded, like an alligator—although gators, in a shocking lack of professional courtesy, are fully capable of chowing down on counsel—or warm blooded, like a bird. This is because creatures capable of maintaining a constant body temperature, regardless of their environment, generally also have the energy to move fast and think quickly. There's only one sure way to settle the debate, but taking the temperature of an animal that's been extinct for 150 million years poses certain obvious problems.

Fortunately, John Eiler, the Robert P. Sharp Professor of Geology and professor of geochemistry, has mastered the art of time travel without leaving the lab. His time machine is a mass spectrometer, a device that separates atoms of different weights in a process he likens to the workings of "a good, old-fashioned television set from the days when TV sets were the size of smart cars." Atoms of a given element that have different weights are called isotopes, and in his Watson Lecture on February 29, 2012, Eiler shows how isotope analysis can not only take a dinosaur's temperature, but perhaps tell us why they died. It's CSI: Jurassic Park.

The Isotope Time Machine” is available for download in HD from Caltech on iTunesU. (Episode 9)

Written by Douglas Smith