Over the past few months, the search for habitable, earth-like worlds orbiting other stars has begun to seem a lot less like finding a needle in a haystack. In January, Harvard-Smithsonian scientists estimated that about one in every six stars in the galaxy has an earth-sized planet. A month later, colleagues reported that potentially habitable worlds might be relatively close, astronomically speaking — just 13 light-years away.
Earlier this month, NASA announced that Massachusetts Institute of Technology scientists will lead a $200 million mission to aid the search for such planets, called exoplanets, and send a refrigerator-sized telescope into orbit around the earth in 2017. The spacecraft, called TESS, will be a powerful tool for scientists, allowing them to scour hundreds of thousands of stars for signs of exoplanets of the right size, temperature, and distance from their suns to support life.
TESS, short for Transiting Exoplanet Survey Satellite, will look at half a million stars in the sky in two years, said George Ricker, a senior research scientist at MIT’s Kavli Institute for Astrophysics and Space Research. It will provide leads for a much more powerful telescope, the James Webb Space Telescope, to scrutinize more closely. That telescope, which will be launched in 2018, will be able to detect signs of water vapor or carbon dioxide in a planet’s atmosphere that could be indicative of life.
Ricker, who will lead the team, answered a few questions about the mission.
Q: How is this different from other missions devoted to searching for earth-like planets, such as the space-based Kepler and James Webb Space Telescopes?
A: James Webb is a large infrared telescope that has a very narrow field of view. Once you have a target, it can actually study the target in detail. But it can’t find targets on its own. . . . Kepler is dedicated to studying this one location in the Milky Way in the constellation Cygnus very, very deeply. . . . The purpose of TESS is to actually look in the full circle of the sky; we’re looking at 400 times [as much sky].
Q: How will TESS aid the James Webb Space Telescope search?
A: The thing that it does do, and I’m sure the NASA people thought about, is that for an [approximately] additional 2 percent investment, by funding TESS, they can greatly improve the productivity that the James Webb Space Telescope will have. And in fact, people have argued that it could certainly improve the productivity of James Webb Space Telescope in this area by 100 percent, because it’s a huge difference. Right now, until TESS flies, we will not know more than one to two candidates [for habitable, earth-like worlds].