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Nice thumbnail sketch of Earth's future by John Baez

  1. May 28, 2007 #1

    marcus

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    http://math.ucr.edu/home/baez/week252.html

    includes a concise timeline of the solar system future

    ===quote Baez===
    * In 1.1 billion years the Sun will become 10% brighter than now, and the Earth's atmosphere will dry out.

    * In 3 billion years the Andromeda Galaxy will collide with our galaxy. Many solar systems will be destroyed.

    * In 3.5 billion years the Sun will become 40% brighter than today. If the Earth is still orbiting the sun, its oceans will evaporate.

    * In 5.4 billion years from now the Sun's core will run out of hydrogen. It will enter its first red giant phase, becoming 1.6 times bigger and 2.2 times brighter than today.

    * In 6.5 billion years from now the Sun will become a full-fledged red giant, 170 times bigger and 2400 times brighter than today. The Republican Party will finally admit the existence of global warming, but point out that it's not human-caused.

    * In 6.7 billion years from now the Sun will start fusing helium and shrink back down to 10 times bigger and 40 times brighter than today.

    * In 6.8 billion years from now the Sun will runs out of helium. Being too small to start fusing carbon and oxygen, it'll enter a second red giant phase, growing 180 times bigger and 3000 times brighter than today.

    But then, about 6.9 billion years from now, the Sun will start pulsating, ejecting half of its mass in the form of solar wind! It'll become what they call a "planetary nebula". Eventually only its inner core will be left. In "week223" I quoted Bruce Balick's eloquent description:

    "The remnant Sun will rise as a dot of intense light, no larger than Venus, more brilliant than 100 present Suns, and an intensely hot blue-white color hotter than any welder's torch. Light from the fiendish blue "pinprick" will braise the Earth and tear apart its surface molecules and atoms. A new but very thin "atmosphere" of free electrons will form as the Earth's surface turns to dust."
    ...
    ...
    ==endquote==
     
    Last edited: May 28, 2007
  2. jcsd
  3. May 28, 2007 #2
    How can the atmosphere "dry out" before the oceans evaporate?
     
  4. May 29, 2007 #3

    Wallace

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    This part I'm not so sure of. The odds of an Andromedan star coming close enough to ours to tidally disrupt the orbits of the planets are very small as I understand it.
     
  5. May 29, 2007 #4

    marcus

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    I have the same impression from what I've read, Wallace. The chance of OUR solar system being disrupted is judged to be slight.

    But I guess it is possible that a fair number of solar systems could be disrupted even if it is a small percentage of the total. Hard to figure. Perhaps he should have said "some planetary systems (but not necessarily ours)" instead of "many solar systems" will be destroyed.
     
  6. May 29, 2007 #5
    This estimate obviously must come from what we know of the life cycle of a star, so if our solar system came from a nebula from a previously passed star and our sun is 4-5 billion years old, then the star that went supernova and eventually formed our solar system must have been born 15 -16 billion years ago at least correct? Or do some stars have shorter lifespans? That star must have been one of the 1st ever formed in the universe....:uhh:
     
  7. May 29, 2007 #6

    Garth

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    More massive stars have shorter lifespans, sometimes much shorter lifespans.

    For a ~10 MSun star the lifespan can be measured in millions rather than billions of years.

    Garth
     
  8. May 29, 2007 #7
    Wow...that IS short indeed! :surprised
     
  9. Jun 15, 2007 #8

    mgb_phys

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    Even knowing that, it is one of the most surprising things in astronomy, how quickly galaxies formed and enough generations of early stars went through their lifecycles to give us our metal rich enviroment.

    ps. love the smiley
     
  10. Jun 19, 2007 #9

    Gib Z

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    LOL.

    "LOL" couldn't be posted because it was "too short".
     
  11. Jun 19, 2007 #10
    ‪‪‪‪‪‪‪ Lol
     
  12. Jun 22, 2007 #11
    ...that sucks

    glad I wont be around
     
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