—By Brett Brownell
Last week, a team of astronomers at the Gemini Planet Imager in Chile released the mysterious blue image above. That small bright dot in the lower right of the image is a planet—not a planet in our solar system like Mars or Neptune, but one 63 light-years away. It's the planet Beta Pictoris b, which orbits the star Beta Pictoris in the southern constellation Pictor. But what's most exciting about the picture is the technology used to make it, which represents a dramatic improvement in the speed and quality with which scientists will be able to look for other planets—including "Earth 2.0," a theorized planet much like our own.
The first confirmation that planets exist beyond our solar system came in 1992, when a team of astronomers monitored changes in radio waves to prove that multiple planets were orbiting a small star about 1000 light-years away. Then, in 2005, astronomers created the first actual image of a planet beyond our solar system (the date is arguable because the observation was made in 2004, but not confirmed until a year later). Since then, hundreds more planets have been discovered, and a few others have even been photographed.
So when Gizmodo reported last week that the blue image above was the "first ever image of a planet, orbiting a star," they didn't have it quite right. In fact, the image wasn't even the first time that planet had been photographed. But the GPI images are still extremely exciting: They could mark the beginning of a new era of planet-hunting, thanks to technology developed by a team of astronomers led by Bruce Macintosh of Lawrence Livermore National Laboratory.
Frank Marchis, who works for the SETI Institute, a nonprofit organization that seeks to explore, understand, and explain the prevalence of life in the universe, is a key member of Macintosh's planet-hunting team. I met with him in San Francisco last week to discuss the project and the search for Earth 2.0:
MJ: What exactly are we seeing in this image?
FM: Behind this image is a lot of work. This image is simply a planet orbiting around another star. So we call that an exoplanet – an extrasolar planet – because it doesn't belong to our solar system. It belongs to another planetary system. So this is the grail of modern astronomy. We're trying desperately now to image those planets because we know they exist. When you observe a planet with [the now defunct telescope] Kepler, what you've been doing is basically detecting the transit - the attenuation of [the star's] light - due to the planet passing between us and the star. Now with GPI, the Gemini Planet Imager, which is mounted at the 8 meter class telescope in Chile we're going to be able to see the planet itself.