Lonely interstellar Earths might roam galaxy

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  • In 2007, astronomers simulated by computer the movement of worlds in space and concluded that Earth-like planets might roam the space between stars.

    Hundreds of millions of systems like our own Earth and moon might be roaming between the stars of the Milky Way galaxy, according to a recent study.

    We know Earth is unique among the sun’s inner planets for having a large moon. But in our outer solar system, Pluto has a moon that’s fully half its own size. It could be that small planets – like Earth or Pluto – might often have their own large moons.

    John Debes of the Carnegie Institution in Washington, D.C., and Steinn Sigurdsson of Pennsylvania State University used a computer to simulate what would happen in a newborn solar system if a planet like Earth with a satellite like the moon passed near a giant planet like Jupiter. The simulation showed that the giant planet’s gravity can eject the Earth-moon system into interstellar space.

    It’s cold and dark out there, far from any sun. But an interstellar Earth might not freeze if its air is thick enough. The accompanying large moon might raise tides in the ocean of such a world, warming the planet and keeping its water liquid for more than a hundred million years. If that scenario occurred, life might arise on this lonely Earth/moon system, moving in the space between stars.

    Our thanks to:

    John Debes
    Carnegie Institution

    8 Comments for Lonely interstellar Earths might roam galaxy

    1. 1
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      Magenta says:

      “It could be that small planets – like Earth or Pluto – might often have their own large moons.”

      YAY!!!!!!!!!!!!!! Pluto’s a planet again!

      I’ll trust Deborah Byrd over the IAU any day.

    2. gravatar

      Oops. I meant “dwarf planet.” :-)

      But thanks for the vote of confidence!

      Deborah

    3. 2
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      Magenta says:

      No you didn’t! You got it right the first time.

      Besides, if the Earth is a dwarf planet, then I’ll be moving elsewhere soon!

    4. 3
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      neil says:

      Of course Pluto’s a planet. It’s a dwarf planet. You wouldn’t say a red apple wasn’t an apple because it’s red, would you?

    5. 4
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      Magenta says:

      No I wouldn’t.

      But the IAU would.

      One of the many problems with the IAU’s vote last year was that dwarf planets are NOT planets.

      I know. It doesn’t make any sense. That’s why wise people are ignoring the IAU. And Pluto is still a planet!

    6. 5
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      Jonathan says:

      So if the earth and moon were to be thrown out of our system. Would our atmosphere be thick enoufgh to keep us from freezing?

    7. 6
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      Bob says:

      Maybe for a hundred years we would still be able to live. But thats just my guess.

    8. 7
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      Magenta says:

      “So if the earth and moon were to be thrown out of our system. Would our atmosphere be thick enough to keep us from freezing?”

      No. But the problem is that the Moon is now so far away from Earth that it doesn’t heat the Earth enough.

      But the answer to your question would be yes if you were asking about an Earth-Moon system, in which the Earth has the Earth’s current atmosphere, but in which the Moon is much closer to Earth — as it was billions of years ago.

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