October 28th, 2010
02:28 PM ET

Lots of Earth-size planets out there, astronomers say

Astronomers observed sun-like stars from the W.M. Keck Observatory in Hawaii.

There may be more Earth-size planets in the universe than astronomers suspect, according to a University of California-Berkeley study published Thursday.

Using NASA's powerful Keck telescope in Hawaii, university astronomers Andrew Howard and Geoffrey Marcy tracked 166 sun-like stars within 80 light-years of Earth, according to their report published in Thursday's edition of the journal Science.

Howard and Marcy found a notable number of planets of the smallest size currently detectable: about three times the size of Earth.

"If we extrapolate down to Earth-size planets - between one-half and two times the mass of Earth - we predict that you'd find about 23 for every 100 stars," Howard said in a press release.

"This is the first estimate based on actual measurements of the fraction of stars that have Earth-size planets," Marcy said.

"What this means," Howard added, "is that, as NASA develops new techniques over the next decade to find truly Earth-size planets, it won't have to look too far."

The trick is to find planets that are the optimal distance from their stars to provide the right temperature range for liquid water and to sustain life, they wrote.

The research was funded by NASA and the W.M. Keck Observatory, which is operated by the University of California and the California Institute of Technology.

The study found just 33 planets circling 22 stars, but previous models had predicted very few or no planets in those ranges, Marcy said.

"One of astronomy's goals is to find eta-Earth, the fraction of Sun-like stars that have an Earth," Howard said. "This is a first estimate, and the real number could be one in eight instead of one in four. But it's not one in 100, which is glorious news."

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soundoff (51 Responses)
  1. Bond James Bond

    im 45 so shes hot, and obviously not fuk shy! And we are and have been being watched, i think they are waiting to see if were going to kill each other, or come together to save ourselves! And ozzy's got cave man in him! Suprised, listen to him!

    October 29, 2010 at 8:41 am | Report abuse |
  2. Roy Lowey-Ball

    I agree. Who could have thoughtotherwise? There are probably millions of planets that can sustain life.

    October 29, 2010 at 8:55 am | Report abuse |
  3. phil

    Yeah there probably is a gold coin in my yard...even though I haven't found it after years of searching.

    October 29, 2010 at 11:02 am | Report abuse |
  4. GB

    Give all the murderers and child molesters a one-way ticket.

    October 29, 2010 at 11:30 am | Report abuse |
  5. WhiteKong78

    The people on this planet have constantly dragged their feet when being nudged towards becoming educated and moral beings. Political correctness (whatever your view of it is) is a lot better than people going around treating each other like dirt. Also why don't we force people on welfare or convicts to get a degree and eventually a job in order to halt the endless cycle of living off the taxpayers? We also need a better education system where parents and teachers are held responsible for consistently bad student performance. Anybody who suggests such things is constantly attacked by political figures or talk show hosts. The term fascist or nazi gets tossed about too.

    October 29, 2010 at 1:14 pm | Report abuse |
  6. WhiteKong78

    @GB a one way ticket where? If you're suggesting the deep south like hades then sure. We could send our convicts to Cuba like Castro did to us in the 80's. I'd support that policy.

    October 29, 2010 at 1:18 pm | Report abuse |
  7. Josh

    Can someone please explain what the term "earth-like" means?

    Does it mean a planet that is like what Earth originally (pre-life) was?

    Does it mean a planet that is like what Earth with life v1.0, that excreted methane and turned the atmosphere pinkish-red?

    Does it mean a planet that is like what Earth with life v2.0, that excreted oxygen and turned the atmosphere blue?

    Does it mean a blue planet with lots of liquid water?

    Does it mean a white planet with frozen water, like "snowball" Earth?

    Does it mean a green planet with chlorophyll (plant) life?

    November 3, 2010 at 9:01 am | Report abuse |
    • GatorALLin

      Nope, just a rock flying in orbit around a star... about our size or slightly smaller....or 10x bigger. Nothing else. so that is not much good as we should look for something our size and about the orbit distance of the earth and hope for 1 moon and not an orbit any closer or farther away than Earth has. Water is critical, but I think is too hard to see or guess at for now. In summary they don't have a clue, but SETI does...I say we keep looking for radio noise.

      November 20, 2010 at 9:56 am | Report abuse |
    • InterestedCanuck

      Unfortunately they have no way of discovering what the earth-like planets consist of, just simply the size of them, distance from the sun and the chemical composition (is it primarily rock, like earth, primarily gas like jupiter, etc.). Think of how difficult it's been to discover water or ice on Mars. They basically look through telescopes that capture light and depending on how much it blocks out of that stars light, the reflection it gives off and it's orbital track they discover size, chemical composition and distance. We're limited outside of that and require something much more powerful and something outside of the o-zone layer (since it distorts all light collection scopes, thus they build high up to avoid more air interference) to discover much more. We're still a little ways away from that.

      September 13, 2011 at 11:29 am | Report abuse |
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