Discovery News: Space Diary

Little Leo

Twinkle, twinkle little star
Are you hiding planets afar?

More and more often, the answer is turning out to be “yes.” The latest discovery: a world just five time larger than Earth circling around its mother star in the constellation Leo. If true, the planet would be the smallest yet found beyond our solar system. More importantly, researchers believe the planet to be of the terrestrial, or rocky body, variety.

A team of astronomers from the Spanish Research Council working with Dr Jean-Philippe Beaulieu, a visiting astrophysicist at University College London, made the discovery using a computer simulation that predicted the planet’s location based on small changes on an already discovered sibling planet.

The scientists say the newly discovered world, called GJ 436c, orbits its host star in 5.2 Earth days and completes a revolution in 4.2 Earth days.

“On Earth, a full day (sunset to sunset) coincides quite closely with the rotation period. On the new planet these two periods do not coincide, since the orbital translation period and the rotation period are very similar. For this reason, a full day on the new planet would take four planetary years, or roughly 22 Earth days,” notes a press release about the discovery.

The study is published in this week’s Astrophysical Journal.

Sheep in space

The announcement this week that scientists using the Hubble Space Telescope have found organic molecules in the atmosphere of a planet outside the solar system reminded me of an interview I had a while back about how researchers might determine if life exists on other planets.

I asked if extraterrestrial scientists were looking at Earth, for example, would they know it was populated. Apparently, one of the give-aways would be the same chemical found in the atmosphere of planet HD 189733b -- methane. We can thank the sheep and cows for providing telltale signs of life on Earth.

It’s doubtful any alien livestock are busy processing dinner on HD 189733b, however. The planet is too close to its mother star to support life as we know it.

Clock Ticks for ET's Call

Within the next two dozen years, astronomers running the California-based SETI Institute looking for little green men, women, and any other being, gendered or otherwise, anyone beyond Earth who has figured out how to build and operate a radio transmitter -- say they will finish their quest.

They’re hopeful it will end with unequivocal proof of a radio signal that bears some sort of resemblance to I Love Lucy, or whatever favored accoutrement adorns an alien broadcast. But if there is still no word from ET by then, the Search for Extraterrestrial Intelligence popularized by Carl Sagan’s 1985 sci-fi novel Contact, then the folks at the SETI Institute, who have been patiently working for the past three decades or so, will concede defeat: Either we are alone in the universe, or the plan to try to find a our cosmic cousins by searching for their TV shows isn't going to work.

So says, Seth Shostak, the loquacious and oratory gifted senior SETI scientist who addressed an overflow crowd at the Florida Institute of Technology in Melbourne last week. His rather bold prediction stems from a meticulous survey, currently under way, of 1 million nearby stars for signs of alien-made radio signals from orbiting planets. The privately funded group recently began using a dedicated array of telescopes in northern California, thanks to seed funds from Paul Allen. In October, SETI scientists and astronomers at the University of California, Berkeley, completed the first phase of a $50 million project, known as the Allen Telescope Array, to build and operate a 350-dish network to look for ET, as well as comb the cosmos for naturally occurring radio signals caused when, for example, stars form, galaxies collide and pulsars miss a beat due to gravity bending around black holes.

Thanks for the visit, Seth. Keep your ears to the ground and your sights on the stars.