Kepler 452b: a Super Earth-Like Cousin Among Many [IN DEPTH]

It looks like the planet Earth is going to need a bigger family tree... NASA recently announced that their planet-hunting Kepler Space Telescope (KST) has discovered the most Earth-like planet ever seen - the latest addition to a list of 12 exceptionally promising and potentially habitable worlds.

According to experts at NASA's Ames Research Center (ARC) in Moffett Field, California, the planet in question, known as Kepler-452b, is 60 percent larger in diameter than Earth and is considered a super-Earth-size planet. While its mass and composition are not yet determined, previous research suggests that planets the size of Kepler-452b have a good chance of being terrestrial, meaning they could also support water or ice.

Planets are Like Fabled Porridge

And that's what is really important here. When Kepler emerged victorious in its revamped mission last December, it proved that despite some technical difficulties, the $600 million mission was still capable of finding planets sitting in a sweet-spot perfect for supporting Earth-like conditions.

This spot, called the "habitable zone," is the space around a star that's not too close to boil oceans, but not too far to completely freeze them. Planets found in this place that's just right for water are aptly called "Goldilocks planets" and Kepler has already identified more than 1000 of them. It is suspected that there are actually billions of such planets just waiting to be found throughout the Milky Way Galaxy alone.

So then what is it that makes Kepler-452b special enough for fanfare? (Scroll to read on...)

"The new discovery, Kepler-452b, fires the planet hunter's imagination because it is the most similar to the Earth-sun system found yet: a planet at the right temperature within the habitable zone, and only about one-and-a-half times the diameter of Earth, circling a star very much like our own sun," NASA excitedly announced on Thursday (Jul 23).

"And the timing is especially fitting" the space agency added, "[as] 2015 marks the 20^th anniversary of the first exoplanet confirmed to be in orbit around a typical star."

Specifically, Kepler-452 - the star that the new planet orbits - boasts about the same temperature as our own Sun (both are type G2), is 20 percent brighter, and has a diameter 10 percent larger. And while Kepler-452b is larger than Earth, the planet is a mere 5 percent farther from its parent star than Earth is from the Sun. As a result, the exoplanet boasts 385-day orbit - breathtakingly similar to our own calendar.

"We can think of Kepler-452b as an older, bigger cousin to Earth, providing an opportunity to understand and reflect upon Earth's evolving environment," Jon Jenkins, Kepler data analysis lead at the ARC, explained in a statement.

"It's awe-inspiring to consider that this planet has spent 6 billion years in the habitable zone of its star," he added, alluding to the fact that Kepler-452 is about 1.5 billion years older than our own Sun. "That's substantial opportunity for life to arise, should all the necessary ingredients and conditions for life exist on this planet." (Scroll to read on...)

A New Home?

So let's say, for austerity's sake, that Kepler-452b does boast all the right conditions, and is just waiting for colonization. Even if we don't find alien life there, what kind of difficulties could future explorers encounter?

Well, for one, the Kepler-452 system is a stunning 1,400 light-years away from Earth, in the constellation Cygnus. For comparison, Mars is 20 light minutes from our big blue world. Gliese-832c, another promising Goldilocks world, was thought to be the most Earth-like of this elite club just last year. That planet is tucked away in the constellation of Grus, a mere 16 light years away, making it a much more viable option for future exploration... you know... after humanity achieves warp drive, and maybe telepathy while we're at it. Hey, a man can dream!

One of the troubles with Gliese 832 c and Kepler-452b is size. Both are estimated to have about five times the mass of Earth.

"Given the large mass of the planet, it seems likely that it would possess a massive atmosphere, which may well render the planet inhospitable," researcher Professor Chris Tinney, Head of UNSW's Exoplanetary Science research group, said in a past news release.

He explained that a super-dense atmosphere could serve like a super-insulator, hot-boxing a planet that would otherwise be cool enough for water and life. (Scroll to read on...)

And even if that's not the case, gravity would be another problem. John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington told reporters in a Thursday briefing that astronauts on Kepler-452b would likely experience twice the gravity that is felt on Earth.

"Gravity really sucks," the ex-astronaut said, adding that luckily, the human body can adapt. "Even in real time, if we were there we'd get stronger, our bones would get stronger; it would be like a workout every day."

I can imagine them now: hulking Keplernians walking around their new-found home on calves the size of basketballs. It's certainly a unique future to aim for.

Kepler-452b is one of 12 exceptionally promising Goldilocks planets newly discovered by Kepler and a smattering of Earth-side telescopes. According to NASA, the Kepler team has increased the number of new exoplanet candidates by 521 from their analysis of observations conducted from May 2009 to May 2013, raising the number of planet candidates detected to 4,696. Candidates still require follow-up observations and analysis to verify if they are actual planets.

"Discovery and Validation of Kepler-452b," was recently accepted for publication in The Astronomical Journal (PDF).

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