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.

Exoplanets: How the Milky Way is Surprising Scientists

Jul 21, 2011

Three prominent researchers discuss how recent findings from the Kepler mission are deepening our understanding of planets beyond our solar system, and expanding our view of where life may exist in the Milky Way Galaxy.

In Search of Another Earth

Artist's rendition of Kepler spacecraft.
Dec 27, 2010

In a three-part series, MIT News explored MIT researchers’ roles in the quest to find an Earth twin and the effort to make sense of the 500 exoplanets that have been discovered since 1995.

ASTRO 2010: Charting the Next Decade in Astronomy

Aug 27, 2010

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.


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