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More hunters join the planet search

A telescope turbocharger called ET has found its first planet outside the solar system, and something that looks like a suitcase in space is tracking possible faraway Earths.
An artist's conception shows a planet at least half as massive as Jupiter orbiting a young star. Scientists say they have detected such a world using an add-on telescope instrument they call the Exoplanet Tracker.
An artist's conception shows a planet at least half as massive as Jupiter orbiting a young star. Scientists say they have detected such a world using an add-on telescope instrument they call the Exoplanet Tracker.P. Marenfeld / NOAO / AURA / NSF
/ Source: Reuters

A telescope turbocharger called ET has found its first planet outside the solar system, and something that looks like a suitcase in space is tracking possible faraway Earths, astronomers reported Wednesday.

These two small, relatively cheap instruments are part of a new wave of tools and techniques joining the accelerating race to find a world like ours that orbits a different star.

Scientists have detected more than 160 so-called extrasolar planets over the last decade. Most have been found by watching for a telltale wobble in the stars they orbit. None so far has been a perfect match for Earth in terms of the planet’s size and its distance from its star.

But the suitcase in space — Canada’s MOST satellite — trained its instruments on a star known to have a monster planet in its orbit, and watched for minute changes in the light emitted by the star, Jaymie Matthews of the University of British Columbia told reporters.

As the big planet went around a star called HD 209458, the light dimmed a bit, just as the light given off from a brightly lit building would dim slightly if a light were turned off in one window. MOST looked for subtle gravitational tugs that might indicate other smaller planets were also circling the star, but detected none.

“We expected that there might be Earth-mass planets here because the planet we know about is weird,” Matthews said at a meeting of the American Astronomical Society. “It’s too big for its mass, and one of the best theories to explain that was that it was being puffed out by the tidal influence of an Earth-mass planet in a nearby orbit. Unfortunately, that does not work.”

ET detects alien world
Ruling out an Earth-mass planet around this star is a first step by MOST toward actually finding one. But it will not be alone in the search for habitable planets: A French mission called COROT is set to launch this year, and a NASA mission called Kepler is expected to launch in 2008.

For now, the search continues for extrasolar planets of any mass, and astronomers announced Wednesday that they have detected one using a small instrument called ET, short for Exoplanet Tracker.

The new planet is located about 100 light-years away in the constellation Virgo. A light-year is about 6 trillion miles (10 trillion kilometers), the distance light travels in a year.

ET, which cost about $200,000 to develop and weighs about 150 pounds (70 kilograms), acts to boost the power of telescopes searching for planets outside our solar system, said Jian Ge of the University of Florida.

At this point, ET is being used to search for planets only around one star at a time, but Ge said it could look around multiple stars simultaneously, and his team is working on a version that would be able to survey as many as 100 stars at the same time.

“We hope to search hundreds of thousands of stars in the next decade, for about 10,000 planets,” Ge said.