Scene from the 1951 film The Thing From Another WorldFor decades, if not longer, we Earthlings have been collectively waiting for that definitive day when we make First Contact with life from somewhere else in the universe, whether it’s a Closer Encounter of the Third Kind kind of advent or the detection of a microbe on another world. Are we there yet? Well, no, not yet–but we may be a healthy step closer to that day now.
On Monday, November 30th, 2009, NASA/Johnson Space Center announced that a recent study strengthens the argument that chemical and structural features in a Martian meteorite—ALH84001—may be evidence of fossilized microbial life on Mars from the distant past. While not absolutely conclusive that the meteorite bears the remains of ancient Martian life, the results of the study show that alternate, non-biological explanations for some of the meteorite’s properties are not consistent with new findings.
Meteorite ALH84001, discovered in Antarctica in 1984 and chemically identified as having originated on Mars, hit the news in 1996 when researchers hypothesized that microscopic features and chemical constituents in the rock could possibly be the fossilized remains of ancient Martian microbial life. The hypothesis was controversial among scientists, and alternate, non-biological processes were offered by opponents as possible explanations for the meteorite’s features.
The recent reexamination of the meteorite was focused on one of the leading non-biological explanations for the existence of magnetite crystals in the sample. Magnetite is an iron-bearing, magnetic mineral that can be produced both biologically and through inorganic processes. Some forms of life on Earth—including microbes–produce magnetite crystals in their cells that help them orient to Earth’s magnetic field.
The NASA/JSC team that performed the new analysis of ALH84001 concluded that new data on the magnetite crystals, obtained with more powerful analytic instrumentation than used in the 1996 study, are not consistent with the leading non-biological explanations. This, they argue, strengthens the biological explanation for the origin of the magnetite.
The new analysis also obtained scanning electron microscope data that yielded more detail on shapes within the alleged microbe fossils. The new shapes that emerged from the data closely resemble shapes within Earthly microbe fossils—further strengthening the hypothesis that the meteorite contains fossils of life, and thus that life at one time existed on Mars.
The evidence for the possibility of life on Mars, past or present, has been growing over the past decade, or longer—evidence that Mars was once much warmer and wetter than it is now, and that it had rivers, lakes, and possibly oceans of water, making it an environment possibly conducive to the formation of life. We have also detected methane rising out of the soil of Mars, which some suggest could be a byproduct of current biological activity, underground.
NASA will continue to examine the Martian meteorite, focusing their study on further detailing the structures of alleged microbe fossils and possible chemical signatures of life that remain in the rock.
So, we’re still waiting for the day—but with all the tantalizing clues emerging from our exploration of Mars and the Martian meteorite, it feels very much like that day is somewhere on the horizon. But, wouldn’t it be ironic if we were to make the first definitive detection of extraterrestrial life right here on Earth, with evidence that’s been just laying around since before the beginning of human civilization?