Are we alone in the universe? Maybe not!
Are we alone in the universe? Maybe not! This artist's conception provided by the Harvard-Smithsonian Center for Astrophysics depicts an Earth-like planet orbiting an evolved star that has formed a stunning "planetary nebula" (AP photos / NASA)
Are we alone in the universe? Maybe not!
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Earth has a few more near-twin planets outside our solar system. They make for tantalizing possibilities in the search for life among the stars.

Astronomers have announced that depending on definitions, they have confirmed three or four more planets that are about the same size as Earth. The planets are in the not-too-hot, not-too-cold "Goldilocks Zone." That means liquid water could form there.

These planets are likely to be rocky like Earth, and not gas giants or ice worlds. They get about the same heat from their star as we get from the sun. That's according to the latest results from NASA's planet hunting Kepler telescope.

But don't book your flights yet.

They may be close to Earth in size and likely temperature in the huge scale of the universe. But they aren't quite close enough for comfort.

Consider two of the new planets. They are the nearest to Earth discovered to date. If they have atmospheres similar to Earth's a big if one would be a toasty 140-some degrees. The other would hover around zero. So says study lead author Guillermo Torres, an astronomer at theHarvard-Smithsonian Center for Astrophysics.

Life conceivably could evolve and adapt to those temperatures, he said.

Oh, and they aren't actually within commuting distance of Earth. Those two are 500 and 1,100 light years away. A light year is 5.9 trillion miles.

What's important, said SETI Institute astronomer Douglas Caldwell, a study co-author, is that astronomers are a bit closer to finding twins of Earth. That will help answer the age-old question: Are we alone?

"These planets do exist. We didn't know that before," Torres said in a phone interview. "What we're really looking for is signs of life eventually. We're not there yet. It will take many years but this is the first step."

Torres' team confirmed earlier discoveries and added new ones. It brought the total known number of planets that are no bigger than twice Earth's size and in the habitable temperature zone to eight or nine. But that's only from a short search of a small part of our galaxy. Torres believes that Earth-like planets are common. He just can't prove it yet.

Torres likes to include one planet that would bump the new findings from three to four. But Caldwell said that planet may or may not be habitable.

Torres and Caldwell highlighted the two new planets that are closest in size to Earth. The closest is called Kepler 438-b. It is only 12 percent larger than Earth. It gets about 40 percent more energy from its star than we do from the sun. So it would probably be warmer, Torres said. It tightly circles a small cooler red star with its year lasting only 35 Earth days. The sun in its sky would be red, not yellow.

It may be hot, but "there are bacteria on Earth that live very comfortably in those temperatures, no problem," Torres said.

The other planet is Kepler 442-b. It is about 34 percent bigger than Earth. But it gets only two-thirds of the energy from its sun as we do, Torres said.

NASA also announced that its planet-hunter telescope confirmed its 1,000th planet outside the solar system. Most are quite unlike Earth and not in the habitable zone. Added to those discovered by other telescopes, astronomers have now discovered more than 1,800 planets that are outside the solar system.

Critical thinking challenge: Why are scientists so interested in planets that are not-too-hot or not-too-cold for liquid water to form? Which forms of life can live without water?

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Assigned 61 times

  • ANDREWLO-bro
    1/14/2015 - 07:36 p.m.

    That would be cool to study for me because I am interesting in researching that. If there is other hum men like things, I wonder will they be friendly or not.

    • nathanielf-Fou
      1/20/2015 - 04:09 p.m.

      I hope we can go there some day and live there, but it's also warmer.

  • KeaganB-1
    1/15/2015 - 05:33 p.m.

    There are three or four earth like planets that could have like. These planets are not to hot but not to cold. These planets can also have liquid. When a planet has could possibly have liquid it is known as "Goldilocks Zone". These planets are rocky, they are not gas planets nor ice planets which is a good thing. Their is a problem though because one planet is about zero degrees and the other is one hundred forty degrees. I think this article is very interesting.

  • juliant-Fou
    1/20/2015 - 04:04 p.m.

    I wish i can go into space.can the sun make popcorn pop in a bag.i want to see a star.

  • gailc-Fou
    1/20/2015 - 04:07 p.m.

    We might not be alone because the universe is infinite, we don't know how big it is but it's big enough to have planets with life.

  • tylere-Fou
    1/20/2015 - 04:17 p.m.

    There might be more life in space and on other planets

  • andrewm-Fou
    1/20/2015 - 04:17 p.m.

    We are not alone one the universe because we have family member and friends. Sometimes people maybe some people talk to there self sometimes.

  • alexisa-Fou
    1/20/2015 - 04:21 p.m.

    It will be awsome finding life in other planets they might be smarter humans or new animals how could it be it a great time finding life in other plaeners

  • evettg-Rog
    1/21/2015 - 02:48 p.m.

    I think this article is very interesting and to answer the question , i believe that scientist are so interested because maybe someday something tragic might happen to this earth and if their is another planet quite as the same as earth then that can help the human race and the other reason is if they are trying to find a planet twins with earth then they have to find one that water can be able to form for us to drink .We humans cant survive without water its what regulates our body temperature and basically 60% of our body is water.

  • meagana-Rog
    1/21/2015 - 03:30 p.m.

    They are in interested in the plants because its not too hot to go on and not too cold. They want to try to discover the water form and want to try to turn it in clean water on here so we can use it and try to make it in to something else.

  • elijahq-Rog
    1/21/2015 - 03:31 p.m.

    i dont think anything can live without water you would get dehydrated and pass out

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