[QODLink]
Americas

Astronomers find most Earth-like planets yet

Best candidates yet found for habitable worlds, including two potentially life-friendly planets orbiting same star.

Last Modified: 19 Apr 2013 00:44
Email Article
Print Article
Share article
Send Feedback
Relative sizes of Kepler habitable zone planets compared to Earth as shown in this artist's rendition [Reuters]

Scientists using NASA's Kepler space telescope have found the best candidates yet for habitable worlds, including a pair of potentially life-friendly planets orbiting the same star, officials have said.

Two of the five planets orbiting a sun-like star called Kepler-62 are squarely in what astronomers call the habitable zone, researchers said in the journal Science as was reported on Thursday.

The habitable zone refers to planets that are are neither too hot nor too cold, and could possibly contain water.

"These two are our best candidates that might be habitable," said William Borucki, Kepler science principal investigator at NASA's Ames Research Centre.

The two planets are slightly larger than ours, and at least a couple of billion years older.

The first, 62e, is about 40 percent larger than Earth. It might be warm and may experience flashes of lightning, said Borucki.

Constellation Lyra

The second, 62f, is about 60 percent larger than our planet, and orbits its star every 267 days, close to Earth's annual trajectory of 365 days.

The planet may have polar caps, significant land masses and liquid water, Borucki said.

Both are orbiting a seven-billion-year-old star some 1,200 light years from Earth in the constellation Lyra.

They are close enough to their star to be warm, but not so near as to boil the oceans. They are far enough to maintain the likelihood of water without freezing the seas solid, Borucki explained.

Computer models indicate the two planets, likely are solid bodies comprised of rock, ice or a mix of rock and ice.

The pair have three sister planets that also circle Kepler-62, but those are too close their parent star and likely too hot for surface water.

Candidate planets

Kepler, launched in 2009, is NASA's first mission in search of Earth-like planets orbiting suns similar to ours.

The telescope measures slight dips in the amount of light coming from target stars that may be caused by planets passing by, or transiting, relative to the telescope's line of sight.

It is equipped with the largest camera ever sent into space in its search for planets as small as Earth, including those orbiting stars in a warm, habitable zone where liquid water could exist on the surface of the planet.

In late 2011, NASA confirmed its first-ever planet in a habitable zone outside our solar system, Kepler 22b, spinning around its star some 600 light years away.

The large size of that exoplanet, at 2.4 times the size of the Earth, however, has left some doubt over whether the planet is rocky, gaseous or liquid.

Another large planet that Kepler has confirmed in the habitable zone, Kepler 47c, is also much bigger than Earth.

So far, the Kepler science team has more than 2,700 candidate planets.

457

Source:
Agencies
Email Article
Print Article
Share article
Send Feedback
Topics in this article
People
Organisation
Featured on Al Jazeera
At least 25 tax collectors have been killed since 2012 in Mogadishu, a city awash in weapons and abject poverty.
Tokyo government claims its homeless population has hit a record low, but analysts - and the homeless - beg to differ.
3D printers can cheaply construct homes and could soon be deployed to help victims of catastrophe rebuild their lives.
Lack of child protection laws means abandoned and orphaned kids rely heavily on the care of strangers.
Featured
Booming global trade in 50-million-year-old amber stones is lucrative, controversial, and extremely dangerous.
Legendary Native-American High Bird was trained in ancient warrior traditions, which he employed in World War II.
Hounded opposition figure says he's hoping for the best at sodomy appeal but prepared to return to prison.
Fears of rising Islamophobia and racial profiling after two soldiers killed in separate incidents.
Group's culture of summary justice is back in Northern Ireland's spotlight after new sexual assault accusations.