The device, called a “time of flight mass spectrometer,” isolates molecules, and then separates them according to weight. Some molecules are very light, such as amino acid. A typical protein consists of a chain of amino acids, and is thus much heavier.
Amino acids are essential for life to form, but their presence doesn’t necessarily mean life is there. The presence of protein, on the other hand, indicates that amino acids have combined to form the basic structure of organic life.
So it’s those larger molecules, or proteins that bear the clear signature of life.
But nature can be tricky, as evidenced by the on-going debate over whether tiny rod-shaped crystals found in the Martian meteorite ALH84001 were formed by geology or biology. Some heavy molecules can be formed by non-biological processes, and sorting out which molecules resulted from which process is the task that now stretches before Fogel.
The problem, as she sees it, is “we don’t even have a complete inventory of proteins here on Earth,” so that’s the starting point.
“What I intend to do with this instrument is look at things like organic matter from meteorites, organic matter that comes from my colleagues here who are doing abiotic [not produced by living organisms] synthesis experiments” as well as proteins that are an essential part of the cells of every living substance, she says.
In a few years, she hopes to have a complete catalogue of which molecules were formed by which processes, and how they changed through fossilization.
Then, maybe in a decade, the instrument in her lab could be downsized to the microchip level and sent off to Mars, or possibly Jupiter’s moon Europa, to search for proteins there. If it finds them, Fogel believes she can compare them to samples in her library and determine their role in a very different world.
Then, at least, we’ll know what we should be looking for.
Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.