Aug 07 2012
Unless you’ve been hiding under a rock, you know that the Mars rover Curiosity successfully landed in Gale crater last night. This is quite a feat, not least because of the rather Rube-Goldberg sequence to successfully land the rover without contaminating it or the surface too much with backsplash from the landing jets. That’s been thoroughly discussed elsewhere, no need to go over it here, except to congratulate all those involved: the dang thing worked!.
With the landing accomplished, it’s now in the hands of the science teams and drivers. I wish them team all success, and hope we see Curiosity crawling around Mars for years to come. With any luck we’ll see data that pins down some of the ambiguous information we’ve been getting from previous probes.
I like to joke that the Vikinglanders, which landed on Mars back in 1976, were designed to answer the question: “Is there life on Mars?”. They landed, took their soil samples, ran their experiments, and beamed back: “Could you repeat the question?”.
The majority scientific opinion is that the Vikings discovered some very unusual soil chemistry, not life. The thing is, the results from the Labeled Release Experiment (basically, put soil on a nutrient medium labeled (chemically tagged) with isotopes and see if you detect labeled metabolic products) returned results which pre-launch criteria stated would indicate life. They changed the criteria later because of odd results from the other experiments: taken together, they didn’t indicate what the scientists believed would indicate life.
Later some of those same experiments would be repeated in relatively barren places on Earth, such as the ultra-dry Atacama Desert in Chile. They didn’t detect life on Earth, either. (More sensitive equipment will detect microbial life even in the Atacama.)
Do I believe there’s life on Mars? I have no data. I believe there could be, and that there almost certainly was once. We know (or are pretty sure) that Mars was once once wet, with a thicker atmosphere. We know that large meteorite impacts with Earth can knock off rocks which will eventually reach Mars, and, much more so, vice versa. We have strong evidence that some microbes could survive such a blasting into space, millenia long voyage, and entry into another planet’s atmosphere. In other words, it’s entirely possible that Mars was cross-contaminated from Earth (or vice versa!) in the early days of the solar system.
I feel pretty safe in predicting that Curiosity won’t answer all these questions either, but it will answer some. And I’m pretty sure it will raise a few more.