Let’s hunt for M-class planets!

This morning I went to the National Academy of Sciences’ Keck building in Washington, DC, to attend a briefing about the latest decadal survey of astronomy and astrophysics .

Like its six predecessors, the current survey, which covers 2012–21, ranks future ground- and space-based missions in order of scientific priority. Unlike those predecessors, the survey identified a new quest in addition to astronomers’ prime directive of understanding the universe and its contents. Now, astronomers really want to find habitable worlds outside our solar system.

Technology is one reason for this newfound enthusiasm for what Mr Spock calls M-class planets . NASA launched its newest planet surveyor Kepler last March. So far, the mission has found more than 300 new extrasolar planets. None has an Earth-like mass and orbit, but Kepler‘s instruments are working well enough to identify one. Followup missions, of the kind envisioned by the decadal survey, could determine whether those Earths have terrains, atmospheres, and oceans that can sustain life as we know it.

There’s another reason—and it surprised me. When the briefing was over, I chatted with the survey’s chair, Roger Blandford of Stanford University. He told me that incoming graduate students want to work on problems to do with finding and understanding planets. “It used to be cosmology that inspired them,” he said.

Star Trek, whose M-class planets notoriously looked like the uninhabited parts of Southern California, has probably been around for too long to have caused the newest generation of astronomers to seek and study new Earths. The discovery of extrasolar Jupiters in the early 1990s might be responsible.

But whatever the source of their inspiration, the new planet hunters are in a sense returning to a style of exploratory science practiced in previous centuries. When Meriwether Lewis and William Clark left Pittsburgh in August 1804, their main goal was to survey the lands acquired by the US in the Louisiana Purchase. Lewis and Clark also found and documented 178 new plants and 122 species and subspecies of animals .

Being a Vulcan and having seen and visited scores of M-class planets, Mr Spock would hardly raise one of his upswept eyebrows if he came across another one. But imagine the thrill that one of today’s graduate students will feel if he or she finds the first extrasolar Earth.