Might as well strike while the iron's hot with this story...if you can call it that yet. I posted it on my Twitter (click here) the other day, but no one reads that.
Everyone is excited because the lovely science-y types over at MSL announced -- well, that something very interesting is about to pop, but that they're checking their data a few more times before they'll announce it (click here). Apparently the SAM instrument (click here -- sorry, if I just code the link in-text, it's not visible) has turned up a discovery of some sort.
Now I'm going to pretend for a few minutes that I'm qualified to speculate on this, because I've been following this mission like nerds follow Joss Whedon. Also, I've actually done coursework on astrobiology, so I know a teensy bit more than the average news reader.
Background info first: the rover has been collecting soil samples on Mars. They scooped and then dumped out the first few, because they want to make absolutely sure that the samples aren't contaminated by anything Earth-originating. It would be pretty embarrassing to claim to find life and later realize that someone sneezed on the shovel (just kidding, they do insane amounts of decon work before it gets launched; there's bona fide international laws about contaminating other planets -- click here). Anyway, the first sample was actually deposited in the spectroscopy machine, and now they're saying they have a discovery.
Overview of Spectroscopy: it's...just really, really cool. Basically, you beam white light into an object and pass the light that comes out the other side through a kind of prism, separating it into its constituent colors. If you're doing emission spectroscopy, what you get looks like a multicolor bar code. If you're doing absorption spectroscopy, you get the opposite -- a rainbow bar with red light at one end and purple at the other, and black vertical lines in certain areas. In both cases, the lines are the fingerprints of elements. Different atoms absorb light of certain wavelengths, always. So those wavelengths, seen together, always point to that particular element. Depending upon the patterns of the lines (and in more sophisticated readings, how much light is absorbed at each wavelength), you can tell what chemicals compose the object you're looking at, without taking it apart, using nothing but light. It's incredible.
So, what do I think they've found? I bet they've found some sort of complex organic molecule, maybe an amino acid or two. The simpler molecules that life are based on (hydrocarbons and other organics) can be found in a surprising range of places in the Universe, from asteroids to nebulae. It seems like the more we look, the more we see that carbons and hydrogens just can't wait to bond into the things our cells are made of, with a little help from cosmic radiation and/or water. However, amino acids and proteins are much harder to form, and don't seem to happen without a lot more prodding (lots of electrical current, or RNA/DNA instructions -- which are proteins themselves, you can see the problem).
It's unlikely that they've found current life, with the amount of radiation that hits the topsoil there, and the lack of water. It's also unlikely that they found dead signs of life, since that would be hard to find on the surface after billions of years, and microfossils are annoying hard to confirm as such. I also think it's improbable, as some naysayers are predicting, that they're going to announce definitively that there is no life. That would be ridiculous to do from a single soil sample.
It would be nice for them to have found something that would make a great headline -- MARS LIFE FINALLY CONFIRMED. But my guess is that they found something that only other scientists and astrobiology nuts are going to be excited about, while science-column journalists for newspapers scratch their heads about how to phrase the real discovery. PREPARE FOR...Prerequisites for Life Tentatively Confirmed on Martian Surface. Shiny.
Update: as one of my readers pointed out, NASA is now trying to retract its previous claims on the SAM instrument readings. They claim that Grotzinger was trying to say that the information it is collecting in general is "for the record books," not a specific finding.
ReplyDeleteI find this a little odd. I had wondered why the MSL site itself wasn't trumpeting about the secretive find. Since they were holding out for a conference in December to share their findings, though, I wasn't too concerned. But to take almost a week to come out and announce that they were misquoted is somewhat suspicious.
I think they did have a blip in the readings, but after reviewing the data again (per their standard procedures), they realized it was an anomaly. Whatever it was...sigh.