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Earth life

  1. Sep 27, 2005 #1
    Sorry for newbie's simple question but when will our earth die ?

    Thank you
  2. jcsd
  3. Sep 27, 2005 #2
    when u mean die do u mean cease to exist or or reach a point where it can support life?
  4. Sep 28, 2005 #3


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    Most of us here, believe the Earth is not a living being.

    But if you mean when people or other animals will die off, or when people make it uninhabitable for themselves, or other animals, or something like that, we can't answer that question, it is completely unknown.
  5. Sep 30, 2005 #4
    When the Sun, Sol, goes Super Nova, in about Five Million Years, prior to that not likely we can destroy all life on the Earth as it is Still beyond our collective powers.

    Remember that there is, are, Microbial Life forms in the very Deep parts of the Oceans that withstand tremendous pressure and HEAT
  6. Sep 30, 2005 #5


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    The sun won't go supernova, it will go red giant, and it will be 5 billion, not 5 million years.
    I doubt that any microbial life could survive when it happens, as the ocean would evaporate completely.
  7. Oct 1, 2005 #6
    Agree, but there are more processes, as the moon continues to recede with some inch or so a year, the Earth spin rate, decreases. Both processes increase the rate of the Earth precession of the equinoxes, especially when the moon has receded to a critical distance making it's orbit unstable due to the gravity of the sun. I'm sure that there are a lot of Astronomers who know exactly when this happens, but I guess we' re talking about orders of magnitude of a billion years.

    At any rate, when the precession rate approaches the rate of the obliquity cycle of the spin axis, resonance will occur (Robutal Lasker etc), causing large deviations of the spin axis, the "chaotic zone".

    Now, one could speculate that the gyroscopic properties of the Earth core and Earth mantle react differently to those dynamics and depart from alignment. This would cause a tremendous friction, heating up the planet many thousands perhaps up to a million degrees. Clearly more than enough to erase all life from Earth.

    But we could continue, this would make the earth loose all volatiles, causing a dense atmosphere of elementary gasses, whilst the spinning continues to decrease. In this stage Earth might look a lot like, for instance, Uranus, a small gas giant spinning about 90 degrees off the vertical. In the end, when the planet cools, many volatiles will have disappeared, like water. Only heavy gasses like CO2 stick with the planet. When the cooling passes about 470 degrees Celsius and all spinning has ceased, then Earth will be the truly identical twin of Venus.
  8. Oct 1, 2005 #7
    Sorry your right on two, :blushing: but the last one 'Microbial Life' was simply in reference to the Idea that we could Nuke it all, and life would still survive it, just not human life.

    As for the Suns exact time, billions is right,but how many is anyones 'best guess' at best.
  9. Oct 1, 2005 #8


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    Yeah, I dare say you're right about the nuking. I misread and thought you meant that thermophilic bacteria would survive the sun's red giant stage.
  10. Oct 1, 2005 #9
    Red giant Stage, isn't that when it goes Nova? a part of the process of that event?
  11. Oct 2, 2005 #10


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    Only stars quite a lot larger than our sun go super nova. A white dwarf (which our sun will eventually become, long after it begins its red giant phase) may pass through a nova phase, but that is different to a supernova.


    If you want to know more, you should probably ask in Astronomy and Cosmology. I don't know an awful lot about this.
  12. Oct 2, 2005 #11
    I had recognized that placing the Super in front of the Nova Had been wrong, I know better, studied.

    The red Giant aspect is a Part of the Expansion, when it starts running out of fuel, prior to contraction that results in the Nova, concept.

    Thanks, just the same though.
  13. Oct 2, 2005 #12
    The book The Life and Death of Planet Earth by Peter Ward and Donald Brownlee attempts to answer the very question you ask. A great read.
  14. Oct 9, 2005 #13
    Correct me if I'm wrong (I was once in 1986, so I'm overdue for a repeat), but white dwarfs only go nova when they are part of a binary system and are having hydrogen dumped on them by their expanding partner. The sun will not go nova. It will expand into a red giant, then shrink to a white dwarf. End of tale. Also, if recent calculations haven't been overturned yet again, then red giants are not as big as we thought and the sun wont engulf the Earth in that phase, just give it a rather good toasting.
  15. Oct 9, 2005 #14
    One for two, yes to the first part, no to the second part, better be updating yourself (1986 to 2005) for the next time, me too.

    Oh Yes a reference to it, from observe .arc .nasa .gov

    {s p a c e d as to inactivate it}
  16. Oct 9, 2005 #15
    Hmm. I think it may still be two for two. That is one of NASAs educational sites. In my experience these are simplistic (which is fine, given there target audience) and notoriously outdated (which is not so good). I note the copyright date on the article is 1999. My memory is telling me the new calculations on red giant dimensions are vintage 2001 +/-. I'll try and track them down and post if I can find them.

    I could not find the particular data I was looking for, but I have run across this.
    The absolute dimensions for a normal giant star are determined precisely………Using spectroscopically determined luminosity ratios at two wavelengths, the light curve solutions yield 3.96 and 8.32 solar radii - both considerably larger than the main-sequence radius for this mass. Andersen et al, Absolute dimensions of eclipsing binaries. XVII - TZ Fornacis: Stellar and tidal evolution in a binary with a fully-fledged red giant
    Astronomy and Astrophysics (ISSN 0004-6361), vol. 246, no. 1, June 1991, p. 99-117

    Even at the larger 8.32 solar radius we have something that would be well inside the orbit of Mercury. Frankly, while this paper confirms my suggestion, I find it very surprising. I shall continue looking.
    Last edited: Oct 9, 2005
  17. Oct 9, 2005 #16
    Well if it gives us a "rather good toasting" as you so elequently put it, then we {all Life} might just all be dead anyways, right?

    Which would answer the original posters question, I suppose.

    It all changes sooooo fast, or maybe it is just cause there is so much to know.

    Who knows? I know, turtle Knows! he knows everything! we will await his return O.K.?
  18. Oct 10, 2005 #17
    I don't think we necessarily have to wait for the red giant phase. The general increase in solar temperature over time is likely to bring irreversible global warming and Venus like conditions in around one billion years. We should plan to be somewhere else by then.
  19. Oct 11, 2005 #18
    A billion years? Oh yes, I do plan on being somewheres else (slightly) before that, in the Ground, probably.
  20. Oct 24, 2005 #19
    billion years... by then this question would be addressed, we'd find a way to protect the planet without leaving.
    Last edited: Oct 24, 2005
  21. Dec 3, 2009 #20


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    Hi Jujubee... if you look at Mars, and you don't find any signs of life there... its because she lost her atmosphere and her oceans when a large object hit her and knocked half of her crust off into space. If that happened to Earth, that would be the day that life was sent into a tail spin and eventually would cease to exist here, too.
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