Lab Confidential: Pop Rocks
Friday, January 20 8:57 am
A computer program generates color-coded maps to represent the chemical elements of meteorite specimens. © AMNH/D. S. Ebel
Each of the 41 intriguing images in Picturing Science: Museum Scientists and Imaging Technologies tells a fascinating story about research or conservation projects. Here’s the second in a series of four snapshots.
To the average person, meteorites look like black, occasionally brown, lumps of rock from space. But Denton Ebel’s new computer program transforms them into a kaleidoscope of colors that holds clues to the early solar system.
Dr. Ebel, curator in the Department of Earth and Planetary Sciences, uses an electron microprobe—what he calls “the workhorse” of the meteorite lab—to send a beam of electrons across a specimen. Spectrometers built into the machine measure the x-rays emitted by each excited element, and then the computer program, written by Ebel, generates a color-coded map of each element in the meteorite.
“They’re not just pretty pictures,” says Ebel of the Warholesque montage of meteorites featured in Picturing Science. “We’re getting quantitative information from qualitative information. Maps are qualitative since they’re not giving you a robust chemical analysis. But once you do the mapping, you can go back with the probe for a very specific chemical composition.”
(Click on the slideshow below for a step-by-step guide to Dr. Ebel’s process and visit the “Studying Meteorites” slideshow on our Flickr page for full captions.)
Since the mineral makeup of a meteorite can vary greatly throughout the specimen, often the only way to understand these objects’ 4.5-billion-year-old histories is to slice the specimens like loaves of bread using a thin wire saw, about the width of a fine human hair.
But the Museum’s new CT scanner, which images specimens in three dimensions, eases the stress of carving up the oldest objects in the solar system. Thanks to this instrument, Ebel can locate areas of interest before putting the meteorite to the blade. He can, as he says with a relieved smile, “cut with intelligence and foreknowledge.”
A version of this story originally appeared in the Winter issue of Rotunda, the Member magazine.
For the first article in the Lab Confidential series, click here.
