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B Questions about the lifespan of the Earth

  1. Apr 14, 2016 #1
    I remember a teacher said that the Sun is approx. only in its mid way of life and so there are still billions of years to go. I am not worried.

    From wild guess, I am pretty sure our Earth will be finished well earlier before that of the Sun.

    We are talking about global warming, water levels, food crisis ,wars and even the crush of outer space rocks etc.. .but all these things would not lead the death of the earth right? And in the worst case scenario, it will only lead to extinction of human? Am I correct?
     
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  3. Apr 14, 2016 #2

    BvU

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    Yep. No reason to worry at all. Scenarios are pretty well worked out and yes, earth will last longer than life on it. Keep sunglasses within reach for use in a few billion years :smile:
     
  4. Apr 14, 2016 #3
    What I find so cool about 'time' and especially the tiny amount we are actually able to experience is that all life on Earth could go extinct tomorrow and in a few lousy billion years a whole new civilization could have evolved and be bustling around all busy and into themselves thinking how cool they were that here they were the "crown of civilization" outliving even their own evolutionary epochs and eras (There is a difference). And if the bacteria somehow escaped the extinction event tomorrow, and each time, we could go through 3 or 4 of these regeneration cycles. Imagine, this could even include the hundreds of millions of years of dinosaur rule, etc, etc. We probably wouldn't even notice that the universe was 'this' big instead of 'that' big because we wouldn't really have anything much to compare it too.
    And, anyone have anything to add or delete from this scenario please do so. That's what is so great about science, ain't it?
     
  5. Apr 14, 2016 #4
    Your "wild guess" is correct. As the sun ages it gets brighter (luminosity increases). As the sun gets brighter, it also gets hotter. In another 500 million years the sun will be 10% more luminous than it is currently. That is sufficient to kill off all complex life on the planet and boil off the oceans. The only life that might exist after that point would be extremophiles. So not only is our sun approximately midway through its lifespan, but complex life on this planet (which began ≈540 million years ago) is also approximately midway through its existence. Assuming something else does not terminate all life before then.
     
  6. Apr 14, 2016 #5

    BvU

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    Yeah, the mice could call it a day and quit their experiment !
     
  7. Apr 14, 2016 #6

    mfb

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    There is not enough time for that. Life took about 4 billion years until humans formed, but it will get too hot to support complex life within about a billion years. The Earth will be around much longer, but without some sort of global engineering it won't be very habitable any more.
     
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