extrasolar planets

These days, every exoplanet discovery is still rich with excitement, as astronomers scrutinize each distant world and consider its possible characteristics. But this could get tedious pretty soon, as the number of confirmed exoplanets climbs into the thousands. When that happens, astronomers and especially astrobiologists will have to start sifting planets according to their interestingness. A new paper to be published next month describes a new two-step ranking system to make this process easier. We spoke to astrobiologist Dirk Schulze-Makuch to get some details.

See that little dot in the upper left corner? It is a planet orbiting a sun-like star. We know of a few hundred planets like this, but this one is special -- we now know it's the first one to have its picture properly taken from Earth.

The adaptive optics system at the Gemini Observatory in Hawaii snapped this photo in the infrared part of the light spectrum. It shows a hot, large Jupiter-like planet near a smallish sun-like star. It was actually found two years ago, but astronomers couldn't be sure they were really looking at a planetary system and not some lucky alignment of objects. Now they're sure.

Astronomers have discovered perhaps the first "super-Earth" with an atmosphere, and say that there's a strong possibility of the planet having liquid water on its surface. That's still no Earth -- super-Earths are bigger than Earth but smaller than gas giants -- but it's darn close compared to other known exoplanets. Perhaps equally stunning, astronomers simply used a small array of 16-inch telescopes that any amateur stargazer could have in their garage or backyard.

Get ready for more interstellar signposts. Astronomers have directly spotted no less than three planets orbiting a star that sits 130 light-years from Earth. The three gas giants are 10 to seven times the size of Jupiter, with their parent star weighing in at 1.5 times the mass of our sun. Both the Gemini North telescope and W.M. Keck Observatory in Hawaii helped scope out the planets through infrared light.

Scientists have shown off a new laser that boasts an incomparable mix of speed, short pulses and power. That's newsworthy in and of itself, but this laser, developed by researchers at the University of Konstanz in Germany and, here in the U.S., at the National Institute of Standards and Technology, could also lead to a 100-fold increase in the sensitivity of observatories searching for extrasolar planets. The laser itself is the size of a dime, and pops out 10 billion pulses per second with an average power of 650 milliwatts.

We've talked in this space in the past few months about detecting the existence of Earth-like planets in other solar systems, and on the educated guesswork which goes into putting a number on the probability of intelligent life existing out there as well. You may remember that the discovery of terrestrial planets is well on its way as technology improves; and that the Drake equation—with all its assumptions—has proved to be remarkably accurate.

News of another extrasolar planet hardly grabs headlines anymore, now that scientists have pushed the count far above 200. But yesterday a group of astrophysicists says it may have uncovered evidence of a foreign planet being born.

Everyone seems to be double-extra-cautiously optimistic about this finding, so dont go running out to your telescope tonight looking for greetings from friendly space creatures.

But in work reported today in Nature, astronomers say they used the Hubble Space Telescopes infrared imager to pick up signs of methane in the atmosphere of a Jupiter-sized planet orbiting a star some 63 million light years from Earth. And methane, an organic molecule, is an indicator of the possible presence of life.