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How Earth Avoided a Fiery Premature Death

Hugh Pickens writes "Space.com has a piece about changing theories of planet migration. The classic picture suggests that planets like Earth should have plummeted into the sun while they were still planetesimals, asteroid-sized building blocks that eventually collide to form full-fledged planets. 'Well, this contradicts basic observational evidence, like We. Are. Here,' says astronomer Moredecai-Mark Mac Low. Researchers investigating this discrepancy came up with a new model that explains how planets can migrate as they're forming and still avoid a fiery premature death. One problem with the classic view of planet formation and migration is that it assumes that the temperature of the protoplanetary disk around a star is constant across its whole span. It turns out that portions of the disk are opaque and so cannot cool quickly by radiating heat out to space. So in the new model, temperature differences in the space around the sun, 4.6 billion years ago, caused Earth to migrate outward as much as gravity was trying to pull it inward, and so the fledgling world found equilibrium in its current, habitable, orbit. 'We are trying to understand how planets interact with the gas disks from which they form as the disk evolves over its lifetime,' adds Mac Low. 'We show that the planetoids from which the Earth formed can survive their immersion in the gas disk without falling into the Sun.'"

3 of 114 comments (clear)

  1. Re:It wasn't like that! by Nefarious+Wheel · · Score: 0, Offtopic

    Your haiku is poor Next line has five syllables! (Facepalm)

    --
    Do not mock my vision of impractical footwear
  2. Re:It wasn't like that! by postmortem · · Score: 0, Offtopic

    Wonderful mods on Slashdot, can't recognize humor unless it explicit says so. My post was meant to be funny. Thanks.

  3. Re:And they said religion has no part in science by The+End+Of+Days · · Score: 0, Offtopic

    Come up with a model that supports your theory and doesn't contradict other things we've observed and you've made it as far as this story. Skip the part about not contradicting observations and you've made your new Genesis.

    The difference isn't even subtle.