Space.com: Closer to the Holy Grail

In this interesting article at Space.com, at: http://www.space.com/scienceastronomy/070424_exoplanet_side.html

Ker Than provides a nice overview of different planet hunting techniques:

The scores of newly identified exoplanets are the result of the numerous techniques now available to planet-hunting scientists. Peg 51 b was discovered using the radial velocity technique whereby astronomers look for slight wiggles in a star’s motion caused by the gravitational tug of orbiting planets. This so-called wobble technique was also used to spot Gliese 581 C.

The transit method, another tool used by planet hunters, requires that a planet pass directly in front of its star as seen from Earth. The planet blocks some of the star’s light that would reach Earth, and this slight dip in starlight can be used to calculate the planet’s size.

Scientists can also spot alien worlds by observing the way a planet-harboring foreground star bends and brightens light from a background star. This technique is called gravitational microlensing. The presence of an extrasolar planet can also be inferred from the dusty debris disks that shroud some stars.

The article also overviews up-and-coming missions by NASA and the European Space Agency to find earth-sized planets:

Stakes in the search for extrasolar planets have risen even higher with the recent launch of the European Space Agency’s planet-hunting spacecraft, COROT, which will use the transit technique to monitor thousands of stars simultaneously. Over the course of its two-and-a-half year mission, it is expected to find up to 40 new rocky worlds, along with tens of new gas giants.

The NASA Kepler mission, scheduled to launch next year, is even more ambitious. The spacecraft would be the first capable of detecting Earth-sized planets in our galaxy. NASA’s Terrestrial Planet Finder mission is currently on the backburner indefinitely, but it would have the same capability as Kepler. If launched, the satellites will mark an important step in the quest to answer one of humanity’s oldest questions: Are we alone in the universe?

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