The Last Perfect Day
From Carl Sagan's Cosmos - The Lives of the Stars
Fast forward to 27m52s for this part of the show, or just play and enjoy the whole thing.
Some five billion years from now there will be a last perfect day on Earth. Then the sun will slowly change and the Earth will die.
There is only so much hydrogen fuel in the sun. When it's almost all converted to helium the solar interior will continue its original collapse. Higher temperatures in its core will make the outside of the sun expand and the Earth will become slowly warmer.
Eventually life will be extinguished, the oceans will evaporate and boil and our atmosphere will gush away to space. The sun will become a bloated red giant star filling the sky enveloping and devouring the planets Mercury and Venus. And probably the Earth as well.
There is only so much hydrogen fuel in the sun. When it's almost all converted to helium the solar interior will continue its original collapse. Higher temperatures in its core will make the outside of the sun expand and the Earth will become slowly warmer.
Eventually life will be extinguished, the oceans will evaporate and boil and our atmosphere will gush away to space. The sun will become a bloated red giant star filling the sky enveloping and devouring the planets Mercury and Venus. And probably the Earth as well.
Fast forward to 27m52s for this part of the show, or just play and enjoy the whole thing.
23/9/2014 8:44 AM
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