Physics and Astronomy Calendar

Nothing has captured the human imagination more than the prospect of life outside our own solar system. We are incredibly fortunate that our generation may for the first time get a peak at other worlds, an opportunity to search for life outside our own neighborhood. NASA is currently engaged in a series of mission studies, one of which is being led from Princeton, for a large space observatory to image extrasolar earthlike planets. Such an observatory could be launched as early as the next decade; it will search for terrestrial planets in the habitable zone of roughly 150 nearby stars and characterize them for the potential to harbor life. It will culminate 20 years of indirect planet finding with the first direct image of an extrasolar Earthlike planet. This talk will discuss the recent history of planet finding methods and two concepts being studied at Princeton for a planet finding space telescope, an internal coronagraph and an external occulter. An internal coronagraph uses specially designed masks in the optical train of the telescope, combined with deformable mirrors and a wavefront control system, to attenuate the light from the star and make the companion planet visible. An external occulter is a large screen (roughly 50 m in diameter) flying far from the telescope (about 72,000 km). The occulter blocks the starlight from entering the telescope while letting the planet light through. I'll describe the technologies behind these two methods and our progress in both mission design and laboratory verification.