Gemini Planet Imager: New Telescope Will Photograph Distant Worlds

Simulation of a planet imaged by the Keck Telescope (left) compared to GPI (right). Image Credit: Images: Christian Marois/Herzberg Institute of Astrophysics and Marshall Perrin/Space Telescope Science Institute

Simulation of planets imaged by the Keck Telescope (left) compared to GPI (right). Image Credit: Christian Marois/Herzberg Institute of Astrophysics and Marshall Perrin/Space Telescope Science Institute

For those who wonder about alien worlds out there, this is an exciting time of discovery. The number of exoplanets found so far is now well into the thousands and rapidly growing. The one downside—if you can call it that—is that these planets, with just a few exceptions, have been discovered by methods other than direct imaging. So there are still precious few actual photos of any of these far-off worlds. But a new “extreme” telescope is set to start changing that.

The Gemini Planet Imager will take planet hunting to the next level, being able to image more planets than ever before. GPI is a telescopic instrument about the size of a small car designed to be attached to the 8-meter Gemini South telescope in Chile. It will use “extreme” adaptive optics to image the planets orbiting their stars.

Other large telescopes also use adaptive optics to compensate for the twinkling effect of stars due to Earth’s atmosphere, but GPI will use a mirror made from advanced silicon microelectromechanical systems (MEMS) rather than glass. The images it takes will be sharper than those obtained previously by other telescopes. At such distances, any planets, even large ones, are just tiny dots of light, but the new images will still be a significant improvement, and more planets will be able to be photographed. GPI is capable of imaging objects ten million times fainter than the parent star!

Schematic diagram of The Gemini Planet Finder instrument, with a person to scale.

Illustration of the Gemini Planet Imager instrument, with a person to scale.
Image Credit: Gemini Observatory

Being able to actually see some of these planets helps to illustrate that they really are out there, and that they are places and worlds in their own right. As astronomer Bruce Macintosh, principal investigator for GPI, puts it, “There’s something satisfying about seeing the little dot.”

GPI will also be able to analyze the light from the planets to determine their mass and composition, including size, temperature, gravity, and the composition of the atmosphere. This will aid scientists in learning just how similar, or different, our solar system is from others. The type of planets it will focus on are larger gas giants like Jupiter, with larger orbits around their stars. Younger and warmer “adolescent” planets will be the easiest to find. Unfortunately, GPI won’t be able to see Earth-sized planets or planets that have closer orbits to their stars. Still, the results will help astronomers better understand the overall structures of other solar systems. It is already known now from Kepler and other telescopes that many of these planetary systems have Earth-sized and even smaller planets, just like ours.

Astronomer Sara Seager of Massachusetts Institute of Technology sums it up this way: “For all we know, GPI could be the next Kepler. They’re bound to find many, many fascinating objects, because it’s a new eye on the sky.”

GPI is scheduled to start its science operations in October of this year.

4 comments to Gemini Planet Imager: New Telescope Will Photograph Distant Worlds

  • Karol

    Critics of space science will chant the tired old mantra of “We shouldn’t spend money to image exoplanets that are so far away, we should spend the money to solve problems here on Earth,” ignoring the fact that the development of technology “capable of imaging objects ten million times fainter than the parent star” is EXACTLY what we need to do to solve problems here on Earth. This money (which is spent right here on Earth, not a hundred light years out in space) drives technology in a way that we cannot even begin to predict. Who knew that the “fix” of the distortion that initially blurred Hubble images would result in vastly improved mamography imaging that has saved countless lives. Who can state with certainty that no young person will view a Gemini Planet Image and be inspired to pursue a career in science, perhaps a Nobel Prize caliber career? Imagine what could be accomplished if space exploration was actually funded to the full value of what it provides to society.

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  • Malreux

    @Karol

    “Imagine what could be accomplished if space exploration was actually funded to the full value of what it provides to society.”

    “This money […] drives technology in a way that we cannot even begin to predict.”

    Do you think there is any tension between these two declarative sentences?

  • Chris Romero

    The problem is people do not know the value other than weather satellites and extinction events. In today’s governmental fiasco era the value of space and related knowledge is overshadowed by the day-to-day survival needs as presented during the dog and pony shows the politicians put on for their constituents. The only exception being when the space industry jobs are directly lost in their area.