AN ANTIDOTE to the periodic blues this country feels over a sense that we can't do anything great anymore is even now parked on Mars drilling holes into its radiation-blasted surface.
The rover Curiosity, after an improbably dramatic Rube Goldberg-like descent to the surface, has made a discovery that, even though anticipated, is astonishing nonetheless: More than 3 billion years ago, Mars most likely supported life.
Not the little-green-people kind of life of science fiction, but microbial life. Curiosity is a rolling chemistry lab the size of a Mini Cooper, as The New York Times described it, and not equipped to search for organic traces. Any actual identification of long-ago life on Mars will have to wait until a 2020 expedition.
But in a rocky formation called Yellowknife Bay, which the rover crossed over what was possibly an old streambed to get to, Curiosity drilled through the surface into a layer called mudstone and, using its little lab, identified sulfur, nitrogen, oxygen, phosphorous and carbon, all essential to sustaining life as we know it.
Curiosity is exploring a promising 96-mile-long crater called Gale, which at one time was apparently a relatively salubrious neighborhood.
"We have found a habitable environment that is so benign that probably if this water was around and you had been on the planet, you would have been able to drink it," Cal Tech's John P. Grotzinger, the chief scientist of the mission, told a NASA news conference.
The Martian surface of 3 billion years ago evidently was a far livelier place than it is today. In addition to rivers and streams, and potentially snowcapped mountains, there were apparently volcanoes that spewed dust that chemically resembles the basaltic lava thrown up by Hawaii's volcanoes.
So what happened?
Explains The New York Times: "With just one-tenth the mass of Earth, Mars was unable to hold on to most of its atmosphere. The inside of the planet cooled, and the volcanoes stopped erupting. The water froze or evaporated and escaped into space. Mars became cold and dry."
Curiosity has 16 months left on its $2.5 billion mission, so there's no telling what discoveries lie ahead of it. But so far it has indicated that the Red Planet once supported life and, given the right circumstances, could support it again.