Direct Imaging

摘要

The Holy Grail of exoplanet searching is direct imaging. If you can gather light from the planet itself, you can get a spectrum and find out the planet's temperature and what it's made of, compare its composition with those of its star and sister planets, and look for signs of life. The problem is that a planet is very close to a star that is a million or more times brighter-a firefly in the glare of a searchlight. Spotting one is not impossible. A handful of planets have been observed by both ground-based telescopes and Hubble. These, however, have tended to be "low-hanging fruit": large planets with wide orbits around dim stars.