An artist's impression of an exoplanet orbiting a red dwarf star. (Image Credit: NASA)
Also known as extrasolar planets, exoplanets are worlds outside of our Solar System. Astronomers have catalogued nearly 2,000 exoplanets in over a thousand solar systems since the first exoplanets were discovered in the early and mid-1990s. Due to their dimness compared to their host stars, their small size and light-years of distance, exoplanets are extremely difficult to observe and study. Telescopes have directly imaged only a score so far, and in little detail. Instead, the vast majority of exoplanets have been observed indirectly, most prolifically via the transit method, whereby a star's brightness dims ever so slightly as an orbiting exoplanet crosses it as seen from Earth. Astrophysicists study exoplanets to learn more about planetary formation and evolution scenarios and to draw comparisons between our Solar System and others. The question of the potential for other worlds to have conditions favorable for the development of extraterrestrial life is explored especially by the field of astrobiology. The discovery of Earth-like worlds remains a major goal of exoplanetary science. Most worlds on record are larger than Earth and have orbits much closer to their stars, which makes them easier to detect given the sensitivity of current instruments.
Following the release of the National Research Council's Astronomy and Astrophysics decadal survey, survey chairman Roger Blandford and committee member Michael Turner discuss Astro2010, as well as the current and future directions of the fields.