Hundreds of Earth-sized planet candidates discovered
December 4th, 2012
11:01 AM ET

Hundreds of Earth-sized planet candidates discovered

By Zaina Adamu, CNN

Could there be extraterrestrial life in our own Milky Way galaxy?

NASA’s Kepler mission, using an orbiting telescope equipped with a 95-megapixel camera and 42 charge-coupled devices, discovered that worlds, one-half to twice the size of Earth, exist in our galaxy.

Kepler is the first mission with the potential to identify Earth-sized planets that exist near the habitable zones of their stars, a landmark in astronomy because the finding could lead scientists to discover that, indeed, life exists in other places besides Earth.

The way Kepler detects planets is similar to how we detect Venus and Mercury from Earth. Every so often, there are events where Venus and Mercury pass the sun, briefly blocking a bit of the sunlight coming to Earth. From our perspective, each of these events, called a transit, is seen as a slow-moving black speck traveling across the sun.

The Kepler telescope searches for changes in the brightness of stars, which could provide evidence that planets are orbiting them.

Once a planet is found, its size can be measured using Kepler’s Third Law of planetary motion, a calculation based on the amount of light lost from a star and the star’s size. Additionally, the star’s temperature can help determine if the planet might be habitable.

Since its launch in March 2009, the Kepler telescope has found more than 2,300 planet candidates.

Other mission highlights include the discovery of the first rocky planet outside the solar system. Kepler scientists found that planets with similar terrain could be widespread in the Milky Way.

“The initial discoveries of the Kepler mission indicate that at least a third of the stars have planets, and that the number of planets in our galaxy must number in the billions,” said William Borucki, Kepler principal investigator at NASA’s Ames Research Center. “The planets of greatest interest are other Earths,and they could already be in the data awaiting analysis. Kepler’s most exciting results are yet to come.”

But there have been some setbacks along Kepler’s journey.

In July, increased friction caused one of Kepler’s four reaction wheels to malfunction. The reaction wheels help control the spacecraft's attitude, the direction in which it is pointed.

“We don't know what caused the wheel to die, but we are continuing to investigate,” said Steve Howell, project scientist for the mission.

Kepler will probably continue its mission with only three wheels because “as far as science and the mission’s objectives, it has had no impact whatsoever,” said Howell.

In a Spaceflight Now article, however, Borucki suggested that if another wheel stops working, the mission would end permanently.

More recently, engineers found that the spacecraft was not in finepoint for a small period of its mission, meaning that the telescope wasn't able to point itself with enough precision to take accurate scientific information. In trying to correct that anomaly, Kepler detected a bigger issue and put itself in safe mode until the telescope's team was able to assess the problem and successfully execute a recovery process.

The spacecraft is now operating as it should and the mission, originally slated to end earlier this year, has been extended for another four years.

This extension will allow Kepler to find other worlds that are in the "Goldilocks zone," not too far from and not too close to their host stars - similar to Earth.

“The Earth isn’t unique, nor the center of the universe. The diversity of other worlds is greater than depicted in all the science fiction novels and movies,” Geoff Marcy, professor of astronomy at the University of California, Berkeley, told NASA. “Aristotle would be proud of us for answering some of the most profound philosophical questions about our place in the universe.”

Kepler mission’s operation phase is directed by the Ames Research Center in Moffett Field, California. NASA’s Jet Propulsion Laboratory managed the development and launch of the spacecraft.

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Filed under: Discoveries • In Space • Kepler
soundoff (13 Responses)
  1. Jules

    In the second paragraph it says "the finding could lead scientists to discover that, indeed, life exists in other places besides Earth". My question is how could they ever determine whether life exists on any of these earth-like planets without actually going there? Is it possible to build a telescope so advanced it could detect signs of life on a planet 30 light years away? The way I see it, the only way to find out is to go there, which is basically impossible... for now anyway.

    February 25, 2013 at 5:57 pm |
    • cmorcat

      90 years to get there at at least a third of the speed of light and then 90 years to bring back proof, not including the years to build a craft to do it. It reminds me of the fact that we can look out a million light years at stars that may for the most part not exist anymore. Imagine the life forms and civilzations that have come and gone.

      February 25, 2013 at 7:03 pm |
  2. Scotty

    Build me a warp drive engine, then we'll talk. Oh, yeah, and make sure we have some fully charged phasers to go with that. There could be Klingons out there!

    December 17, 2012 at 6:33 pm |
  3. Portland tony

    The laws of Probability have long predicted the possibility of millions if not billions of planets throughout interstellar space. The same laws have indicated a certain number being habitable or, for that matter, inhabited by some lifeform. The problem that I see is no matter how hard we try, the current laws of physics will never allow the human race to come face to face with any of these remote lifeforms!

    December 7, 2012 at 5:39 pm |
    • I'm from Missouri

      @Portland: actually, there are no such laws. There is nothing at all that says there must be other inhabited worlds. That's not how probability works.

      December 17, 2012 at 6:21 pm |
  4. Kenoscope

    Send another up, a larger more sensitive system with better backups. These results are too important for the intelligent to ignore.

    December 5, 2012 at 5:34 pm |
    • I'm from Missouri

      Interesting, but it proves nothing. Right here in our Solar system, we find three planets in the Goldilocks Zone, but only one of them appears to have ever had life and you're on it. There could be trillions of planets close enough to their stars to allows for life, but it wouldn't mean that there's actually been life on them, now, in the past, or in the future. Even on Earth, for most of the time there's been life it wasn't technologically advanced life. If the dinosaurs had not gone extinct, humans would never have existed. A whole series of "lucky accidents" resulted in life on earth and another series of such lucky events resulted in us. How many planets get so lucky? We only have one set of data for that, and among all the planets we've identified so far, the answers seems to be 1. Keep looking, yes, but let's manage our expectations.

      December 17, 2012 at 6:30 pm |
      • BMc

        Wow! So, the Dinosours would not have stopped humans from existing. It was Inevitable. Just like it is inevitable that human existence on this planet in limited. The Earth changed, Oxygen levels dropped, (whether astroids, or comets caused it or not) the ice ages limited the number of plants and animals on the earth. So, in a way "lack" of life gave way to more life. Consistently advancing and adapting. If we are 1 planet with life, that is a number, numbers have odds, probability...It may be one out of a billion or trillion, but there are more planets than we can count. Life will be found eventually. We are lifeforms... We are in space... We are not as advanced as we thimk we cant even keep from killing ourselfs! but look want we can do!

        January 4, 2013 at 12:07 am |
  5. cmorcat

    Based on this article we can only assume the existence of planets that transit their sun by the perspective of the Kepler. Wouldn't that be only about 50% of the planets that actually revolve around a sun that the Kepler is observing? We don't have a way to detect the planets that are revolving around a sun at a perpendicular plain to the line of sight via the Kepler. Can someone smart comment on this observation?

    December 5, 2012 at 1:33 pm |
    • Rutger

      Unfortunately we do not have another way of detecting planets from that distance away. Sure we can set up a telescope and see Jupiter but the planets that they're referring to would be something like 100,000,000,000 x further away. So we can only rely on the travel of light and the variances created in that light. (As they stated the sun they orbit may be 100,000,000 SQMT so a variance in the amount of light that is .0001% of that gives us an idea of the size of it and the tracking of that planet as it completes it's orbit gives us a rough idea of it's distance) With that in mind we don't have the capabilities for it now. Furthermore to a habitable planet – and what is often overlooked – is that it would likely require something like Jupiter to protect it. Jupiter's orbit and sheer size shields Earth from a lot of debris or asteroids that may be travelling toward us. There is a theory that, if a planet were to survive long enough to sustain evolutionary life, it would require a "shield" planet such as Jupiter. I couldn't agree with Kenoscope more. We need to continue this research and continue our research on effective space propulsion. If we're to succeed for another 10,000 years as a civilized society we're going to need a habitable planet or a planet to draw resources from. Either that or we smarten up and go "green" some more. My moneys on a habitable planet...

      December 6, 2012 at 9:40 am |


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