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Lunar eclipse paints portrait of Earth that could aid hunt for distant habitable planets.The rosy glow of a lunar eclipse helped astronomers capture the Earth's transmission spectrum.Daniel Lopez Astronomers have seen what the Earth's atmosphere might look like from outer space by using the Moon as a giant mirror. Sunlight that bounced back from the Moon carried a fingerprint of the Earth's atmosphere that could help astronomers determine if the extrasolar planets they're finding harbour life.The astronomers, at Spain's Institute of Astrophysics of the Canary Islands, made their observations on 16 August 2008 during a lunar eclipse — in which...

A Europan Scenario Between living dirigibles on gas giants and potential organisms under the ice, we’ve had quite a week in terms of exotic life-forms. I didn’t have space in yesterday’s review of Unmasking Europa to talk about the book’s chapter on biology, but here’s an interesting glimpse of a not implausible biosphere on that moon, as presented by physicist Richard Greenberg:

Next week brings a milestone in the search for extraterrestrial life with the scheduled launch Friday of NASA's Kepler satellite. The mission, named for 16th- and 17th-century German astronomer Johannes Kepler, will study a group of stars for three-plus years in search of subtle, periodic dips in stellar brightness—the telltale signs of planetary orbits. Although more than 300 planets outside the solar system have already been found using this method, among other techniques, Kepler's strength will lie in its instruments' sensitivity to smaller, cooler planets more hospitable to life and more like our own. In a new book, planetary scientist...

Detecting Alien Vegetation Could we find evidence of vegetation on distant exoplanets? The answer may be yes, according to recent work by Luc Arnold (Observatoire de Haute Provence) and team. If green vegetation on another planet is anything like what we have on Earth, then it will share a distinctive spectral signature called the Vegetation Red Edge, or VRE. The new paper creates climate simulations that explore whether planets with a distinctively different climate than modern Earth’s could be so detected.Two earlier eras are useful here. The Last Glacial Maximum (LGM) occurred 21,000 years ago, with global temperatures on...

Finding Terrestrial Worlds in the Dust October 13th, 2008 Computer simulations are showing us how to detect the signature of Earth-like planets — indeed, planets nearly as small as Mars — around other stars. That interesting news comes out of NASA’s Goddard Space Flight Center, where a supercomputer named Thunderbird has been put to work studying dusty disks around stars similar to the Sun. Varying the size of the dust particles along with the mass and orbital distance of the planet, the team led by Christopher Stark (University of Maryland) ran 120 different simulations. “It isn’t widely appreciated that planetary...

Researchers are racing to find the first planet that might support life as we know it.Gliese 876 is a modest star, just one-third the mass of our sun and only 15 light-years away, but it has a history-making planetary system all its own. In 1998 a team led by Geoff Marcy of the University of California at Berkeley detected the first sign of something interesting there: a giant planet, twice the mass of Jupiter, circling Gliese 876 once every two months, its gravity yanking the star back and forth at the speed of a jet plane. Three years later the...

How large a planet is depends upon its composition and mass. Earth is largely made of silicates, with a diameter of 7,926 miles at the equator. Imagine an Earth mass planet made of iron and youÂ’re looking at a diameter of a scant 3000 miles. Interestingly, the relationship between mass and diameter follows a similar pattern no matter what material makes up the planet. Running the numbers, an Earth mass planet made of pure water will be 9500 miles across. Sara Seager (Massachusetts Institute of Technology) has been studying these things as part of a project to model the kind...

The search for planets orbiting other stars, otherwise known as "exoplanets", is unearthing new discoveries at an ever increasing rate. In fact, this is one of the fastest-developing aspects of humanity's investigation of the Universe. This and other themes are explored in the Open University's new series Cosmos: A Beginner's Guide. At the last count there were at least 244 known exoplanets. More than 40 of these celestial bodies have been discovered in the first seven months of 2007 alone.

On Monday morning at the American Astronomical Society meeting in Honolulu, an international team of astronomers announced the discovery and identification of 28 new extrasolar planets. This largest-ever announcement, made by post-doctoral fellow Jason T. Wright and newly minted Ph.D. John Asher Johnson, both of the University of California-Berkeley, brings the total number of planets known outside our solar system to 236. "In the last year we've found 37 substellar objects," says Wright, "the 28 new planets constituting more than 10 percent of those now known." Wright reported that 7 of the substellar objects are thought to be brown dwarfs,...

When I was growing up in the '50s, there was a long list of things I was told never would happen. A Catholic never would be elected president, there never would be an end to the Cold War and we never would know what killed the dinosaurs. Those predictions turned out to be wrong. John F. Kennedy won the White House in 1960, the Soviet Union fell in 1991 and most scientists now agree that the dinosaurs were killed by an asteroid. However, there was still one thing I was sure I'd never live to see: evidence of life on...

Astronomers have found the most Earth-like planet outside our Solar System to date, a world which could have water running on its surface. The planet orbits the faint star Gliese 581, which is 20.5 light-years away in the constellation Libra. Scientists made the discovery using the Eso 3.6m Telescope in Chile. They say the benign temperatures on the planet mean any water there could exist in liquid form, and this raises the chances it could also harbour life. "We have estimated that the mean temperature of this 'super-Earth' lies between 0 and 40 degrees Celsius, and water would thus be...

Munich, April 24: An international team of astronomers from Switzerland, France and Portugal have discovered the most Earth-like planet outside our Solar System to date. The planet has a radius only 50 percent larger than Earth and is very likely to contain liquid water on its surface. The research team used the European Southern Observatory’s (ESO’s) 3.6-m telescope to discover the super-Earth, which has a mass about five times that of the Earth and orbits a red dwarf already known to harbour a Neptune-mass planet. Astronomers believe there is a strong possibility in the presence of a third planet with...

In the film Star Wars, Luke Skywalker gazed at a twin sunset from his desert homeworld The dual suns that rise and set over Luke Skywalker's homeworld in the film Star Wars may be more than just fantasy, according to data from Nasa.In a classic scene from the 1977 movie, the hero gazes into the distance as two yellow suns set on the horizon. Nasa's Spitzer Space Telescope has found that planetary systems are as common around double stars as they are around single stars, like our own Sun. Details of the research have been published in the Astrophysical...

This could be a banner year in the search for alien planets. Earlier this month, a new European satellite began its mission to spot planets as they orbit in front of their stars. Meanwhile, a research team has demonstrated the power of that technique by using Hubble Space Telescope data to trace activity in the outer atmosphere of an alien world. It's the first time such meteorological details have been gathered from a planet in another star system. Astronomers have found 209 "exoplanets," the name they give to alien worlds. More could be reported at any time. Observers have found...

One half of the camera is designed to look for planets; the other half is optimised to detect the subtle variation in a star’s light, caused by sound waves rippling across the surface. These waves are the equivalent of seismic waves on the Earth... The technique is known as asteroseismology. ESA’s Solar and Heliospheric Observatory (SOHO) has been pioneering similar investigations of the Sun for many years. It has proved to be an extremely successful way to probe the internal conditions of a star and astronomers are eager to extend the technique to other stars. COROT will target at least...

Newswise — The steady discovery of giant planets orbiting stars other than our sun has heightened speculation that there could be Earth-type worlds in nearby planetary systems capable of sustaining life. Now researchers running computer simulations for four nearby systems that contain giant planets about the size of Jupiter have found one that could have formed an Earth-like planet with the right conditions to support life. A second system is likely to have a belt of rocky bodies the size of Mars or smaller. The other two, the models show, do not have the proper conditions to form an Earth-size...

A FIFTH terrestrial planet may once have orbited between Mars and Jupiter. Although gravitational disturbances would have sent the planet hurtling into the sun or out into space long ago, traces of this long-gone world may still be visible in part of the asteroid belt today. Recent simulations have suggested that the gas giants of our solar system formed with circular orbits but moved into their more elongated paths about 4 billion years ago – 700 million years after the solar system formed. While the gas giants were in circular orbits, rocky planets should have formed in stable orbits out...

Habitable, Earth-like planets can form even after giant planets have barrelled through their birthplace on epic migrations towards their host stars, new computer simulations suggest. The finding contradicts early ideas of how planets behave and suggests future space missions should search for terrestrial planets near known "hot Jupiters". Many of the 160 or so known extrasolar planets are hot Jupiters - massive planets that are closer to their stars than Mercury is to our Sun. But the planets probably did not form in these scorching regions because there would not have been enough gas and dust there to amass such...

NASA Announces Spitzer Planet Finder Update Astronomers using NASA's Spitzer Space Telescope will hold a media teleconference at 1 p.m. EDT Wednesday, April 5 to announce the discovery of a strange place where planets might be forming.

Marc Kuchner at Goddard Space Flight Center is aiming to attack a question that has puzzled us since we first peered into the heavens: Are we alone in the universe? Kuchner came to the Greenbelt research center six months ago from Princeton to step up a search for habitable Earth-like planets outside our solar system. He is writing a proposal for NASA funding for a new space hunting probe and, over the next few years, plans to hire a staff of five or six researchers for the fledgling ExoPlanets and Stellar Astrophysics Laboratory. The size of the staff will depend...