SETI Radio: Story of the Discovery of 'Earth's Twin'

SETI Radio explores the fascinating story of the discovery of "Earth's Twin," exo-planet Gliese 581c, which scientists have called “just right” for supporting life. The recently-discovered planet is not too hot, not too cold…which means it could harbor liquid water.  You’ll hear how scientists draw on their understanding of our own Earthly body to shed light on planets beyond our solar system.

Gliese 581c is the smallest planet yet discovered outside the solar system, and has about twice the gravitational pull of our planet. Creatures on the planet would need thick bones and sturdy legs due to the stronger gravitational pull.

 

This newly discovered planet revolves around the star known as Gliese 581, a red dwarf in the Libra constellation. It is older than our solar system and its year lasts only 13 days, since it is 14 times closer to its star than the Earth is to the our Sun. That is a very good sign, because red dwarfs are less than half the size of the sun, and cooler. In the area where the planet has been discovered, surface temperatures would be very similar to Earth’s between 0C and 40C (32-104 F) just right for oceans to have formed and life to flourish.

Astronomers also say—based on high tech models and density-mass calculations—this quasi-Earth’s surface is either rocky or ocean-covered—both Earth-like geographical qualities. With the discovery of Earth’s twin come high hopes of large strides forward in the search for extraterrestrial life.

The planet was found by Swiss, French and Portuguese astronomers using the European Southern Observatory's 3.6m telescope at La Silla in Chile.

Chris Tinney, a member of he world's largest and most prolific team of planet hunters, the
Anglo-Australian, California and Carnegie Planet Searches, thinks that “finding a planet of Earth mass is probably a couple of years away. But…”—and he emphasizes the “but,” pausing for a moment—“there’s always a ‘but.’” As he explains, all of the things they are finding of very low mass are moving in very short orbital periods, which means that they are orbiting close to their parent stars. So although there they are like Earth in terms of their mass and size, these planets are very unlike the Earth in terms of their orbit.

“To find an Earth-mass planet in an Earth-like orbit is just not going to happen with the Doppler technique,” Tinney states. It is simply beyond the technology currently developed. Essentially, it would mean that they would need to be performing measurements 100 times better than any technology is capable of doing.

So does this rule out the possibility of finding a habitable planet?

Not quite. There is a “trick” to planet hunting. Scientists can look for Earth-mass planets in short period orbits around lower mass stars. These types of stars are called M dwarfs and have a mass one tenth the size of the Sun, which means that the velocity signal is ten times larger, and therefore the radius at which the planet must be from the star in order to have water or liquid on its surface is much smaller. For now, it’s Tinney’s opinion that some of the recent reports about habitable planets being discovered “is more hype than reality,” but that the discovery of such planets “will come in due course.”

Also discussed in the SETI Radio program are the contributions of amateur astronomers and the unexpected tragedy that gave rise to modern astronomy.

• Vikki Meadows – scientist at the California Institute of Technology and NAI member
• Stuart Clark - author of The Sun Kings
• William Phelps- astronomy enthusiast
• Jascin Leonardo Finger -curator, Mitchell House

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Related Galaxy posts:

Cruising the Goldilocks Zone -The Search for Super Earths
Dead Zones in the Search for Extraterrestrial Life

 

Comments

[qwerty]

Anybody ever think that maybe lower gravitational pull on an early earth may have contributed to the size of the dinosaurs? Maybe a gravitational shift destroyed the dinosaurs. Maybe they just became... too.. heavy?

[ramkumar]

THE discovery of Gliese 581c by gravitaional lensing is the first step in the finding of super earth and inturn adds value to Fermi's paradox .(Note: the value "N' no of earth like planets with stars .To think that we are the only intellegent species in the milky way (forget the billion/ trillion galaxies or rather enchanting yet hypothetical mutiple bubble universes ) is rather arrogant & non sceintific.Perhaps in a century we would have done our priliminary research regarding the Icy oceans of Europa the enigmatic moon of our Gas gaint .