Heavens

COLUMBUS, Ohio -- Scientists are expanding the search for extraterrestrial life -- and they've set their sights on some very unearthly planets.

Cold "Super-Earths" -- giant, "snowball" planets that astronomers have spied on the outskirts of faraway solar systems -- could potentially support some kind of life, they have found.

Such planets are plentiful; experts estimate that one-third of all solar systems contain super-Earths.

New research suggests that turbulence plays a critical role in creating ripe conditions for the birth of planets. The study, to be published in The Astrophysical Journal, challenges the prevailing theory of planet formation.

Using three-dimensional simulations of the dust and gas that orbits young stars, the study demonstrates that turbulence is a significant obstacle to gravitational instability, the process that scientists have used since the 1970s to explain the early stage of planet formation.

One of the moons in our solar system that scientists think has the potential to harbor life may have a far more dynamic ocean than previously thought.

If the moon Europa is tilted on its axis even slightly as it orbits the giant planet Jupiter, then Jupiter's gravitational pull could be creating powerful waves in Europa's ocean, according to Robert Tyler, an oceanographer with the University of Washington's Applied Physics Laboratory and author of a letter in the Dec. 11 Nature. As those waves dissipate, they would give off significant heat energy.

Moons outside our Solar System with the potential to support life have just become much easier to detect, thanks to research by an astronomer at University College London (UCL).

The NASA/ESA Hubble Space Telescope's international team of researchers has discovered carbon dioxide in the atmosphere of a planet orbiting another star. This is an important step along the trail of finding the chemical biotracers of extraterrestrial life, as we know it. These findings have been published in the Astrophysical Journal Letters, 9 December 2008.

The Jupiter-sized planet, called HD 189733b, is too hot for life. But new Hubble observations are a proof-of-concept demonstration that the basic chemistry for life can be measured on planets orbiting other stars. Organic compounds can also be a by-product of life processes and their detection on an Earth-like planet may someday provide the first evidence of life beyond Earth.

Previous observations of HD 189733b by Hubble and the Spitzer Space Telescope found water vapour. Earlier this year Hubble found methane in the planet's atmosphere.

The students were testing a method of investigating the light fluctuations of thousands of stars in the OGLE database in an automated way. The brightness of one of the stars was found to decrease for two hours every 2.5 days by about one percent. Follow-up observations, taken with ESO's Very Large Telescope in Chile, confirmed that this phenomenon is caused by a planet passing in front of the star, blocking part of the starlight at regular intervals.