It seems that announcements of newly-discovered exoplanets are occurring on an almost weekly basis these days — 961 confirmed, at last count — but the hunt continues for a truly Earth-like world. And even with 20 exoplanets categorized as “potentially habitable,” the real determination of their capability to harbor life as we know it will only come with investigation of their atmospheres, a tricky task considering the inherent proximity of habitable worlds to their host stars.
When you realize that the sun’s diameter is 109 times that of Earth’s, you can imagine how difficult it would be to spot our own life-covered planet from even a moderate cosmic distance.
That’s where NASA’s starshade comes in. Like an enormous origami sunflower, the starshade would work in tandem with a space-based telescope to block the glare from target stars, allowing their planets to be observed directly and their atmospheres studied in intricate detail.
The secret is in the starshade’s “petals,” which, once unfurled to their full 34-meter diameter, are specifically designed to reduce the bending of light around the edges.
“Less light bending means that the starshade shadow is very dark, so the telescope can take images of the planets without being overwhelmed by starlight,” said Dr. Stuart Shaklan, lead engineer on the starshade project at NASA’s Jet Propulsion Laboratory.
Watch a video of the starshade in action and in development below:
Launched along with a space telescope, the starshade would then use an onboard propulsion system to position itself ahead of the telescope and between observation targets. Alternatively it could also be used with existing telescopes, like the upcoming James Webb Space Telescope, slated for launch in 2018.
It may just be that “flower power” is what NASA needs to spot Earth’s true twin.
“A starshade mission would allow us to directly image Earth-size, rocky exoplanets, which is something we can’t do from the ground,” said Jeremy Kasdin, a Princeton professor and principal investigator of the starshade project. “We’ll be able to show people a picture of a dot and explain that that’s another Earth.”