The Houston Chronicle reports that NASA will make a big announcement regarding Mars on Monday morning. The NASA press release was vague, but the headline was “Mars Mystery Solved.” NASA big guns will be at the announcement, indicating that it will be, indeed, major news.
The chattering classes, astronomy division, are speculating that it is highly unlikely to involve the discovery of life — which would be the biggest news story of the year by a factor of a hundred, so you’d have the president showing up for that — but instead will involve the discovery of flowing water.
Flowing water is regarded as one of the essentials of life, at least life as we know it. So if there is liquid water on Mars, the odds that we will find life there goes up markedly. After all, life evolved on earth not long after conditions settled down enough to allow it. That might indicate that life evolves quickly where it finds suitable conditions, which were to be found on early Mars before its magnetic field disappeared and most of its atmosphere escaped into space. If those conditions exist on Mars today, in however restricted areas, then, while we are certainly not going to find little green men waving at the camera of one of the rovers, a life form analogous to bacteria might well be found. Once it got started here, life proved to be extraordinarily tenacious, surviving all sorts of environmental changes. There’s no reason to think it wouldn’t be equally tenacious on Mars.
There’s a big plus to finding such life. If we have a second, separately evolved form of life to study, we can learn much about the essential nature of earth life. If Martian life were to prove to be based on DNA, as all earth life (except a few viruses that are based on RNA) is, it would indicate a common origin. DNA is a highly complex molecule that is hardly likely to have evolved separately on neighboring planets. More likely one planet seeded the other (or a third one seeded both). If Martian life is not based on DNA, then its chemistry would yield heaven only knows what information.
But there’s also a big minus to finding life on Mars. As Greg Reynolds points out, it will hugely complicate the exploration and exploitation of our nearest planetary neighbor. We don’t have to worry about contaminating the moon as nothing could possibly live in the airless, waterless wasteland of its surface or below.
But if Mars suddenly has the possibility of life, then all probes will have to be very, very carefully sterilized for fear of letting earth life reach Mars and perhaps spread there, utterly disrupting Martian biology. Equally true, returning materials from Mars would be very problematic for the same reason. H. G. Wells wrote a bestselling book (subsequently made into several movies, not to mention a radio program that panicked part of the country) about a Martian invasion. Bacteria-like life might be far more effective in wiping out humankind than Wells’ fearsome Martian war machines.
The human exploration of Mars — not yet on the drawing boards because of its huge cost — would become even more expensive by at least an order of magnitude. Machinery, after all, can be sterilized, but humans are walking zoos of microbial life and we can’t live without many of those tiny symbiotic creatures comfortably ensconced in our guts.
So whatever is revealed on Monday, it’s likely to be a blockbuster. As Rick Moran explains, “One thing is sure, it better be good. NASA has raised expectations so that nothing less than Mars-shattering news will justify the dog and pony show on Monday.”