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.
Armed with new knowledge about how microbes persist even in the Earth’s harshest environments, astrobiologists are planning the next missions to search for life in our solar system. Their bets are on microbes.
During a recent Google Hangout, three astrophysicists discussed what we can learn about the planets in other solar systems, and answer viewers' questions about how close we are to discovering other Earths. Read a modified transcript of their discussion.
During a recent Google Hangout, three astrophysicists discussed the recent exoplanet discovery boom and considered the next steps in the hunt for habitable worlds. Read a modified transcript of their discussion.
The Brain or the Universe – Where Does Math Come From? OnAugust 7, 2013,three leading scientists - two neuroscientists and one astrophysicist -– answered your questions about this debate during a live Google Hangout.
Planets adrift in space may not only be common in the cosmos; in the Milky Way Galaxy alone, their number may be in the quadrillions. Standford astrophysicist Louis Strigari talks about these nomadic wanderers after a recent research paper that generated attention when it greatly increased the estimate for the number of these planets, renewing speculation about life beyond Earth.
In the ongoing hunt for planets beyond our own solar system, spacecraft in coming years will focus their telescopes on the nearest stars – those in our immediate neighborhood of the Milky Way galaxy.
An artist's impression of an exoplanet orbiting a red dwarf star. (Image Credit: NASA)
