New, far-out planet is discovered

A planet discovered in the constellation Sagittarius is so distant that light takes 5,000 years to travel from there to here at a speed of 186,000 miles per second. Called OGLE-TR-56b, the planet orbits too close to its sun to be hospitable to living things. The way it was found could lead to the discovery of more planets like our lively Earth. “We have found a better way to detect new worlds in our own Milky Way galaxy, which makes future planetary discoveries easier,” says Dimitar Sasselov, Thomas D. Cabot Associate Professor of Astronomy at the Harvard-Smithsonian Center for Astrophysics. Astronomers can’t see such planets directly, even with the most powerful telescopes. They are too small compared with the stars they orbit, and they generate no light of their own. But the new planet, some 115,000 miles in diameter, minutely dims the twinkle of its star when it passes between the star and light detectors on Earth. Sasselov compares it to solar eclipses seen when our moon passes between the sun and Earth. The dimming or transit technique is so sensitive it should allow astronomers to spot planets as small as Earth that orbit in our Milky Way neighborhood.