Imaging planets around stars

This is cool. [Link]

Webster Cash (University of Colorado at Boulder) has spent the last five years working on a starshade that could function with the upcoming James Webb Space Telescope. The cost: $700 million to image alien Earths around nearby stars, a fraction of the price of the original TPF-C and TPF-I concepts worked up at the Jet Propulsion Laboratory.

We’re not talking about those Goldin-style images of Earth-like worlds on the schoolhouse wall, at least, not with the earliest generation of starshade. But Cash does believe we can use the early starshades to get a spectrum of an Earth-like exoplanet within the next ten years. That could flag the presence of oceans and even reveal signs of life.

Here’s Billings’ description of the operative technology:

Cash’s starshade would resemble a many-petaled sunflower—if sunflowers were matte-black and about half a football field in diameter. Its special shape is designed so that waves of starlight will diffract around it, lapping against and nullifying each other to cast an ultra-dark shadow, ensuring that only an exoplanet’s light falls on the JWST’s huge mirror. Equipped with small thrusters, the starshade would fly some 70,000 kilometers in front of the JWST, precisely aligning to block light from a target star so that its accompanying planets could be seen.

Read the article for more on this (and, if you’re looking for further background, run a search on this site for stories on Cash’s work). And keep this in mind. Astro2010 is a decadal survey of astrophysicists put together by the National Research Council, one that will soon release a report on research priorities for the coming decade. Cash’s starshade has been submitted to the committee, and so has a competing starshade concept by David Spergel and Jeremy Kasdin (Princeton University), former Cash collaborators. Will the committee support a starshade?