The search for life on other worlds ramped up again yesterday when...
The Mars Phoenix lander touched down in the far north of the Red Planet, after a 680 million-km (423 million-mile) journey from Earth.
The probe is equipped with a robotic arm to dig for water-ice thought to be buried beneath the surface.
It will begin examining the site for evidence of the building blocks of life in the next few days.
Phoenix is just the latest in a wide ranging group of programs, at least part of whose goal it is to detect life elsewhere in the universe.
SETI continues to scan the skies looking for intelligent signals of non-terrestrial origin. Enlisting the public in the search, SETI allows thousands of non-scientists to participate by having standard pc's analyze the data SETI collects. You can download the software do just that here.
To date astronomers have detected over 230 extraterrestrial planets orbiting other stars:
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.
Raising the stakes
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?
That's if Earth-bound astronomers don't make the discovery first. The discovery of Gliese 581 C showed the radial velocity technique could spot planets much smaller than scientists had predicted only a few years ago.
Here's an interesting video on the topic:
The Phoenix lander is an important contribution to what is becoming a crowded field of study.
Hot Air also reports on the landing