2009-10-03

"It could happen almost any time now. We now have the technological capability to identify Earth-like planets around the smallest stars."

David Latham -Harvard-Smithsonian Center for Astrophysics

To date, Planet hunters have spotted more than 300 planets beyond our solar system, but the vast majority are hot, Jupiter-sized planets that would dwarf the Earth and are almost certainly lifeless.

A few weeks ago, the first rocky planet was found outside solar system, but the surface temperature is far too hot to sustain life. The planet, called CoRoT-7b, is the first planet beyond our solar system with a proven density similar to Earth's, astronomers say. Most known exoplanets are large gas giants like Jupiter.

The tiny planet was discovered orbiting a star slightly smaller and cooler than our sun, about 500 light-years away. As the planet passed in front of its star, it eclipsed a small portion of the star's light, causing a dip in brightness.

Astronomers may be on the brink of discovering a second Earth-like planet, a find that would add fresh impetus to the search for extraterrestrial life. Astronomers from six major centers, including NASA, Harvard and the University of Colorado, agreed at a conference last year that advances in technology suggest scientists are on the verge of being able to detect the presence of small, rocky planets, much like our own, around distant stars for the first time. The planets are considered the most likely habitats for extraterrestrial life.
Finding a rocky planet with an Earth-like density brings us one step closer to discovering another planet similar to our own. A twin-Earth beyond the solar system could provide the best chance of finding life elsewhere in the universe.

The majority of the atoms in our bodies were created in the Big Bang 15 billion years ago. Most of the mass in our bodies are oxygen atoms that were created by generations of stars that preceded the formation of our Sun. We are a subset of the physical universe. And through astronomy this negligible subset is slowly acquiring -however limited- an awareness of the total universe that created it.

The great thing about outer space? It's absolutely full of fantastic stuff just waiting for us to be able to see it: every time we improve our observations, either the equipment or analysis, something new and brilliant jumps out of the universe saying "Here I am!" Now fans of interplanetary ideas have been rewarded with the very first rocky planet outside the Solar System.
Everything we've seen previously has been some Jupiter-like gas giant, a huge ball of not-solid-stuff-like-Earth that's still interesting but - since we don't imagine meeting alien clouds very much - not as exciting. But it isn't the case that space only features balls of gas, it's just that our technology couldn't see anything smaller. Until now.

A collaboration between the COROT and HARPS systems has detected a rocky expolanet five hundred light years away, a small stone ball less than twice the diameter and about five times the mass of Earth - giving it the same density as our place. Don't imagine any aliens just yet though (or if you do, make them pretty heat resistant) - it orbits only 2.5 million kilometers from its star, sixteen times closer than even Mercury gets. The expolanet's "year" is thus shorter than our day - meaning that even if there is an asbestos-based civilization their economy is utterly devastated by birthdays.

COROT is the COnvection ROtation and planetary Transit satellite, scanning thousands of stars to see the tiny dips in brightness caused by planets. HARPS is the High Accuracy Radial Velocity Planet Searcher, a super-sensitive spectrograph installed on a Chilean telescope to accurately identify how fast a wavelength source moves. Between them, they were able to identify the location of the planet and work out it's orbital radius and speed, thereby working out the mass and size. And with names like that, they probably combine to form Voltron's big brother.

It's awesome stuff for scientists. Yet another example of how we'll never be bored, how the universe is simply stuffed with things waiting for us to detect them.

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