Preposterous Universe

 
Water on Mars

So it looks like there used to be a lot of water on Mars.

This is a great discovery. There's so much we don't know about the origin and evolution of planets and their chemistry, any little bit of information helps. The evidence seems to be somewhat indirect (sulfate concentrations, shapes of rocks), but I'm willing to believe that it paints a compelling picture.

Still, I have profoundly mixed feelings about this. Of course, the result is immediately spun as evidence for the possibility of life, with some intentional ambiguity about how strong the possibility is, when the life might have died out, or what form it took. More than one of the scientists comes right out and says that this part of Mars would have been an hospitable environment for life to exist. Really? Just because there was water? Wouldn't we need to know a little more than that to make such a sweeping statement?

Discovering solid evidence for life native to Mars (as opposed to some organic material that was splashed there from Earth, as we now know can happen after comets or meteors impact us) would be a truly wonderful event. But it's not very likely. For one thing, it's just hard; I can imagine a long series of experiments reaching inconclusive results. For another, the a priori chances that life evolved separately on Mars seem incredibly small. There seem to be a lot of planets in our galaxy (one hundred billion, maybe?), but yet the galaxy is not teeming with the electromagnetic buzz of numerous advanced civilizations (the Fermi paradox). Either civilizations destroy themselves with extremely high probability, or life comes into existence with extremely low probability. Choose for yourself which seems more reasonable.

But still, it would be well worth chasing after this remote possibility if it didn't cost anything. (Warning: curmudgeonly realism ahead.) But this finding will certainly be used as justification for funneling yet more money away from other NASA science programs and into the Mars program, especially into the manned mission which Bush recently proposed. Which is just silly.

The space shuttle and the space station were part of a NASA strategy to make travel to Earth orbit cheap and routine, which is certainly a laudable and achievable goal. The problem is, it's been an abject failure. Shuttle missions are infrequent, unsafe, and fantastically expensive; the space station is even worse on all counts. So the new strategy is to build a base on the Moon and then visit Mars? This is like a kid who can't quite get the hang of riding a bike without any training wheels, who decides that everything would improve if he enters the Tour de France. Not that it's not a worthwhile goal (either the Moon or the Tour de France), but it's not necessarily right under any circumstances. And we're just not there yet.

Meanwhile, the rest of NASA's science budget is being strangled. I gave a colloquium at the Space Telescope Science Institute on January 14th this year; the starting time had to be delayed so that everyone could listen to the President's announcement of the new initiative, which had been (coincidentally, one assumes) scheduled for the same time. The sense of dread in the room was palpable; here were dozens of dedicated scientists, who were devoted to using this fantastic instrument to discover new things about the universe, who could see it being undermined before their eyes. And indeed, soon thereafter the planned servicing mission (to install $200 million of new equipment, which has already been built) was canceled. Safety was certainly a major concern in the decision, but money was a crucial factor.

And Hubble is not the only thing to go. I was recently on a NASA "roadmap team" to sketch out a future plan of missions in cosmology and astrophysics. We came up with the Beyond Einstein program, an ambitious but practical set of missions to learn about black holes, dark matter, dark energy, and the early universe. In the President's new budget, all of the new missions were pushed back several years; of course they can continually be pushed back until they never happen. I have a vested interest in this kind of science, it's true; but by any objective measure the most successful science missions that NASA has done have been unmanned satellites, not sending people around the solar system. Our scientific decisions are being increasingly driven by spectacle and political calculation, which is a shame when there are such exciting results potentially within reach.

It's terrible that I can't simply enjoy a wonderful scientific result for what it is, but automatically start fretting about the wider political consequences. Must be a grownup or something.

~ posted by Sean Carroll at 4:48 PM ~ link ~ ~ ~