We’ve been thinking about life on Mars for a long, long time.
At first it was easy. Before the telescope, Mars was a brilliant spark of orange light that moved about the sky with the other planets, seemingly with a life of its own. Its light grew and faded as its distance changed, and it would routinely reverse its course through the stars in retrograde ebbs. Long ago, many cultures saw Mars, and the other visible planets, as living beings themselves: deities that journeyed through the heavens.
After the invention of the telescope, and especially in the late 19th-century when they got powerful enough to see some details on Mars’ face, it was still pretty easy to think about Mars and life, though life on Mars, and not Mars as a living being, was the main fare for the imagination. Polar ice caps reminiscent of Earth’s and perceptible surface markings and color variations, both of which changed in extent and detail with Martian seasons, seemed to make Mars—or the human imagination—pulse with life. Fiction writers and scientists alike speculated on the existence of vegetation, animal life, liquid water, and even intelligent civilizations existent on the Red Planet.
But as our telescopes grew even more powerful, and especially when we started sending cameras and telescopes to Mars on robotic spacecraft, imagining Martian life became more challenging. Even the first robots to land on Mars only added to the sterile picture of a lifeless Mars. It seemed that the possibilities of finding life there were drying up like the dusty, rusty, desert planet itself.
Last week I heard a rumor, which many of you heard as well, that NASA is preparing to make a big announcement concerning Mars and a recent discovery by the SAM instrument on board the rover Curiosity. People have been asking, “What big announcement is NASA going to make? Will it really be earth-shaking, as some have suggested?”
NASA is qualifying the rumor—which spread through the blogosphere and Twittersphere like cyberfire—with a sober and soundly scientific assessment that the announcement (expected on Monday) will be scientifically interesting, but not earth-shaking.
Given that the SAM instrument (a set of chemistry experiments including a mass spectrometer, a laser spectrograph, a gas chromatograph, and a pre-subinertial photomegatronic oscillator—okay, only kidding about the last one) is designed to find organic compounds required by life as we know it, I’d say that the announcement will have something to do with organic compounds. I’m not being flippant; my point is that SAM (and Curiosity for that matter) was not designed to find life, fossils, remains or excrements of life, or even megalithic pyramids created by intelligent civilizations. (Although, the latter would certainly show up on one of Curiosity’s cameras if it were pointed in the right direction….)
Curiosity was sent to Mars to assess the suitability for life in Mars’ past. Other missions (Spirit and Opportunity, Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter) have revealed that liquid water, one basic requirement for life as we know it, very likely once flowed on Mars. But life (AWKI) also requires the right mix of organic compounds—compounds of nitrogen, oxygen, hydrogen, and carbon—to emerge, form, and thrive.
That is Curiosity’s charge, a mission that will unfold over the next two years as the rover climbs the slopes of Mount Sharp, a huge pile of sedimentary layers formed over the last 2 billion years or so–the very pages of the book of Mars’ geologic history. Read on, Curiosity, read on!
I think the wildfire of speculation, the furor of questing curiosity that erupted and became amplified by cyberspace, is an indication that we, as a culture and a species, are still looking for life on our neighbor planet; still hunting for life there, still wanting, hoping, to find it. I’m optimistic that we may find it, eventually—and in the meantime, I only have to wait until Monday to hear the latest from NASA, whatever exactly that will be.