NASA edges closer to finding a new Earth for humans

6 Dec 2011

Artist's perception of Kepler-22b. Image by NASA/Ames/JPL-Caltech

Feeling weary of hearing terms like ‘budget’, ‘downgradings’ and ‘bond markets’? Well, maybe Kepler-22b, a new planet NASA has discovered, will offer some hope. Apparently, this planet offers the best scope yet for a new human abode, other than planet Earth.

NASA’s Kepler mission, which incidentally started in 2009, has just discovered Kepler-22b, which the space agency says is known to “comfortably” circle in the habitable zone of a “sun-like star”.

But, what does this mean exactly for us mere mortals?

NASA has confirmed that because the planet, which it has named Kepler-22b, has been found to orbit in a star’s habitable zone, this is the region around a star where liquid water, a requirement for life on Earth, could persist.

And because Kepler 22-b is 2.4 times the size of Earth, NASA says this makes it the smallest planet yet found to orbit in the middle of the habitable zone of a star like our sun.

Kepler 22-b in the context of the solar system

600 light-years away

Kepler-22b is 600 light years away from Earth. While the planet is larger than Earth, its orbit of 290 days around a sun-like star resembles that of our planet. NASA says Kepler-22b’s host star belongs to the same class as our sun, called G-type, although it is slightly smaller and cooler.

Scientists do not yet know if the planet has a rocky, gaseous or liquid composition.

NASA scientists have confirmed, however, that it’s possible that the world would have clouds in its atmosphere, as depicted in the artist’s interpretation (main image).

Kepler space-borne telescope lift-off 6 March 2009


It was back on 6 March 2009 that the Kepler space-borne telescope was launched from Cape Canaveral Air Force Station in Florida. Pictured above is United Launch Alliance’s Delta II rocket carrying NASA’s Kepler spacecraft rising through the exhaust cloud created by the firing of the rocket’s engines. Liftoff was on time at 10.49pm EST.

Into the cosmos

Kepler itself is designed to search the nearby region of our galaxy for Earth-size planets orbiting in the habitable zone of stars like our sun.

Kepler discovers planets and planet candidates by measuring dips in the brightness of more than 150,000 stars to search for planets that cross in front, or “transit” the stars, says NASA. Apparently, it requires at least three transits to verify a signal as a planet.

NASA says the challenge for Kepler is to look at a large number of stars in order to statistically estimate the total number of Earth-size planets orbiting sun-like stars in the habitable zone.

During its travels across the Milky Way, Kepler is destined to survey more than 100,000 stars in our galaxy.

Kepler has also has discovered more than 1,000 new planet candidates, nearly doubling its previously known count. Ten of these candidates are near-Earth-size and orbit in the habitable zone of their host star, NASA has confirmed.

“Candidates require follow-up observations to verify they are actual planets,” added the space agency.

Kepler-22b discovery: NASA comments

“This is a major milestone on the road to finding Earth’s twin,” said Douglas Hudgins, Kepler programme scientist at NASA headquarters in Washington.
“Fortune smiled upon us with the detection of this planet,” said William Borucki, Kepler principal investigator at NASA Ames Research Center at Moffett Field, California. Borucki led the team that discovered Kepler-22b.

“The first transit was captured just three days after we declared the spacecraft operationally ready. We witnessed the defining third transit over the 2010 holiday season.”

The Kepler science team uses ground-based telescopes and the Spitzer Space Telescope to review observations on planet candidates the spacecraft finds.

NASA said yesterday that the “star field that Kepler observes in the constellations Cygnus and Lyra can only be seen from ground-based observatories in spring through early fall. The data from these other observations help determine which candidates can be validated as planets”.

Carmel Doyle was a long-time reporter with Silicon Republic