Ex­o­planet is Earth’s clos­est ‘cousin’

SundayXtra - - FRONT PAGE - By Mar­cia Dunn

CAPE CANAVERAL, Fla. — Sci­en­tists have iden­ti­fied a “close cousin” to Earth that’s or­bit­ing a sun-like star and might har­bour life. The re­searchers an­nounced their dis­cov­ery Thurs­day based on ob­ser­va­tions from NASA’s Ke­pler space te­le­scope.

“It is the clos­est thing that we have to another place that some­body else might call home,” said Jon Jenk­ins, the lead data an­a­lyst from NASA’s Ames Re­search Cen­ter in Cal­i­for­nia.

This older, big­ger cousin to Earth is called Ke­pler452b. What makes this planet re­mark­able is it or­bits its star at about the same dis­tance Earth or­bits the sun. What’s more, its home star looks to be sim­i­lar to our sun.

Based on what sci­en­tists know to­day, Jenk­ins added, “This is the clos­est thing we have to another Earth-sun twin sys­tem.”

John Grunsfeld, NASA’s science mis­sion chief, said the ex­o­planet sys­tem “as far as we can tell, is a pretty good close cousin to the Earth and our sun.” The planet it­self is “the clos­est twin, so to speak, to Earth 2.0” yet found in the Ke­pler data.

“This is about the clos­est so far,” Grunsfeld said, “and I re­ally em­pha­size the ‘so far.’ ”

One unan­swered ques­tion is whether the planet is rocky. Sci­en­tists be­lieve there’s a bet­ter-than-even chance it is. As for age and size, the planet is about six bil­lion years old — 1.5 bil­lion years older than Earth — and 60 per cent larger in di­am­e­ter than our home planet. Its star, Ke­pler- 452, is also older and big­ger, as well as brighter than our sun.

Planet 452b takes 385 days to or­bit its star, just a lit­tle more than Earth takes for a one-year lap. It’s just a bit far­ther from its star than Earth is from our sun.

The planet is in a so­lar sys­tem 1,400 light years from our own, lo­cated in the Con­stel­la­tion Cygnus, or swan.

“So pack your bags — it’s a long trip,” joked Jenk­ins.

Planet 452b is among more than 500 new en­tries listed in the Ke­pler team’s latest cat­a­logue of ex­o­planet can­di­dates re­leased Thurs­day. Ke­pler was launched in 2009 to hunt for ex­o­plan­ets — worlds be­yond our so­lar sys­tem.

Of those 500-plus new po­ten­tial plan­ets, 12 are less than twice Earth’s di­am­e­ter and also or­bit­ing in the so-called hab­it­able zone of their star, also known as the just-right Goldilocks zone.

Ke­pler- 452b is the first of those 12 to be con­firmed as a true planet, thanks to ground ob­ser­va­tions.

Al­to­gether, the cat­a­logue now in­cludes 4,661 ex­o­planet can­di­dates. Slightly more than 1,000 of them are con­firmed to be plan­ets.


This artist’s ren­der­ing from NASA shows a com­par­i­son be­tween the Earth (left) and the planet Ke­pler- 452b.

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