September 15, 2006

Search for Life in Space Continues

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A century ago, Percival Lowell published his now infamous work Mars and its Canals. The work, which sparked international controversy and hysteria, conjectured that surface markings seen through his telescope were large canals transporting water from the polar ice caps to the equatorial regions.

He theorized that ancient Martians built the canals to support their civilizations in the warmer and “drier” regions. Since then his theory has been disproved dramatically with better telescopes and eventually small Cornell-led rovers. But the quest for life continues with the hopes of someday answering, “Are we alone?”

While intelligent life most likely does not exist in this solar system, the turn of the millennium and the technology over the last decade has allowed the beginnings of a new search. This search is no longer bound to the eight planets orbiting our sun but instead will focus on the hypothetical millions of planets orbiting the millions of stars of the night sky. But before these planets can be searched for extraterrestrial life, they need to be found.

Finding planets millions of light years away was impossible 50 years ago and even today remains a significant challenge. Approximately 200 extra-solar (outside of our solar system) planets have been discovered and they have been found indirectly.

Rather than imaging the planet itself, astronomers detect them by studying the stars they orbit and the effect that planet has on its parent star. This detection method finds only planets that are either very large or orbit very close to the star. Building better telescopes and taking advantage of the science of light is the key to solving this riddle.

Using a method known as interferometry, multiple telescopes can be combined to create even better pictures. Prof. John D. Monnier, University of Michigan, explained yesterday to a room full of Cornell astronomers about his use of this technique while studying early solar systems. Understanding how solar systems form and evolve into a planetary system like the one we live in will help astronomers predict the abundance and orbits of planets around their parent stars.

Our solar system was once just a giant cloud of gas that began collapsing under the weight of its own gravity. Originally spherical, the gas falling inward will start with some initial rotation and as it falls faster and faster inward, will begin to spin. This spinning flattens the sphere into a disc and it is from this disc of dust and gas that the planets form. Most of the gas falls all the way to the center and creates the sun, but everything else in the solar system is formed from what’s left.

Sound pretty simple? Hardly. Astronomers have spent countless hours attempting to understand the processes that guide this evolution and besides a few basic outlines, much is still actively debated between different camps. It won’t be until the next generation of telescopes that astronomers will be able to describe this evolution completely.

Hopefully with a better understanding of where planets come from the search for E.T. can span the heavens.