Do you dream of discovering other worlds, and possibly alien life? You should have been there last night in Pasadena, when Caltech co-hosted a special panel discussion with the Thirty-Meter Telescope and Discover Magazine. And they brought in a stellar line-up.
Bad Astronomer Phil Plait -- All-Around Mensch and Moderator with the Most -- led a conversation with four leading scientists at the cutting edge of searching for exoplanets and extraterrestrial life: Gibor Basri of UC-Berkeley, who is associated with the Kepler Mission; Sara Seager, a planetary scientist and astrophysicist from MIT; Tori Hoehler, an astrobiologist at NASA's Ames Research Center; and John Johnson of Caltech, a promising young exoplanet hunter whom Plait jokingly dubbed "John-John" -- just for making him feel old. (That's Discover editor Corey Powell front and center, with, left to right, Johnson, Hoehler, the Badass Astronomer, Basri and Seager.)
It's easy to forget that just a scant 10-15 years ago, the prospect of extrasolar planets was considered a bit of a fringe idea in science. Even if they were out there, how could we find them? There were rumors of an exoplanet in the 1980s, but the discovery was never confirmed. Really, it wasn't until 1992 that two radio astronomers (Aleksander Wolszczan and Dale Frail) found planets orbiting the pulsar PSR 1257+12, and had their discovery promptly confirmed. But it was still a bit shaky. Then, on October 6, 1995, two astronomers at the University of Geneva (Michael Mayor and Didier Queloz) made headlines when they announced a definitive detection of an exoplanet orbiting 51 Pegasi.
As Basri and Johnson pointed out, statistically speaking, the odds are such that if you find one exoplanet, you can safely assume there are at least 200 others. As high-resolution spectroscopic techniques got better and better, and astronomers figured out how to find exoplanets by measuring their gravitational effects on the motion of their parent stars, that assumption proved to be conservative.
To date, we have found 452 exoplanets... and counting. Heck, John-John -- excuse me, "Dr. Johnson" -- just co-discovered the second smallest extrasolar planet yet back in January, with a mass just four times that of Earth, orbiting the star HD156668 about once every four days. (Not too shabby, Dr. Johnson). Basri expects that the Kepler Mission will be reporting evidence for a number of "Earth-sized" planets very soon -- just as soon as the team members finish weeding out all the false positives. (Kepler looks for variations in a star's apparent luminosity as an orbiting planet passes in front of it to detect extrasolar planets.)
Of course, exciting though this prospect is, that's just the first step. Seager and others were careful to emphasize that "Earth-sized" does not necessarily mean "Earth-like." After all, Venus is an Earth-sized planet but its atmosphere and surface characteristics are nothing like Earth's. It's Seager's job to use computational modeling of exoplanet atmospheres and interiors to develop telltale "biosignatures" in atmospheric gases that might indicate possible ingredients for life. It's a budding young field, and Seager is among the trail-blazing pioneers.
And even then, we're not done yet! Hoehler is taking his background in chemistry and oceanography and applying it to study "microbial community dynamics in extreme and analog environments." That's Geekspeak for spending a lot of time looking at the features of deep-ocean hydrothermal vents, or Arctic glaciers, to see under what conditions (even extreme ones) certain kinds of life might thrive. That "life" might be nothing like our carbon-based forms here on Earth, which makes Hoehler's job all the more difficult -- and exciting.
That's just a taste of what proved to be a thoughtful, substantive -- and even entertaining -- conversation, to whet your appetite for more. Because I have no doubt that video of the event will be available shortly, since the entire discussion was filmed for posterity. In the meantime, for your viewing pleasure, here's a gratuitous clip (without sound) from last summer's Star Trek reboot, wherein every geek's favorite fictional exoplanet, Vulcan, gets pwned by a black hole. Feel free to debate the physics in the comments!
Tags: Alien Life, Astronomy, Astrophysics, Extrasolar Planets
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