• Question: What Will Cause The World To End? (even though i believe that god will come for judgement day)

    Asked by tiioshax to Daniel, Jon, Louise, Sharon, Zoe on 21 Jun 2010 in Categories: . This question was also asked by mrboffy.
    • Photo: Sharon Sneddon

      Sharon Sneddon answered on 20 Jun 2010:

      Gosh, that’s a really hard question, and I don’t really know! I’d like to think that it will never end, but keep on evolving in some way!

    • Photo: Louise Dash

      Louise Dash answered on 20 Jun 2010:

      Our planet will probably end when our star, the sun, expands into a red giant class star, which astrophysicists think will happen in around 5 billion years time.

      However, life on earth, or even the whole planet, could be destroyed earlier if a nearby star becomes a supernova in a massive explosion, or if we are hit by a giant asteroid.

      There’s nothing much we can do about these possibilities, and they almost certainly won’t happen within our lifetimes, so they’re probably not worth worrying too much about!

      But there’s also the possibility that humankind could be destroyed by its own actions – like a global thermonuclear war or uncontrolled global warming. It would be good if we could avoid this! It’s probable though that even if humankind becomes extinct, some life will survive on the planet and become dominant, much like mammals have done after the dinosaurs became extinct.

    • Photo: Jon Copley

      Jon Copley answered on 20 Jun 2010:

      If by the “end of the world” we mean the destruction of the Earth, then in about five billion years time, the Sun will run out of its hydrogen fuel (which is slowly getting converted into helium by nuclear fusion). At that time, the Sun will expand to become a Red Giant star, with a radius greater than the current orbit of the Earth.

      People have suggested that the Earth will get burned up during that solar expansion. But the Sun will also have lost 30% of its mass by then, so it will have less gravity and the orbits of all the planets will shift outwards. So the Earth will actually move to a more distant orbit at first. But it looks likely that orbit will not last, because of tidal effects that cause it to decay, eventually dragging the Earth to a firey end. Here’s a New Scientist magazine article about that research: http://www.newscientist.com/article/dn13369?feedId=online-news_rss20

      However, if we think of “the end of the world” as the end of life on Earth, then that will happen much sooner – in just a billion years time. The Sun is gradually getting brighter and hotter (and has been for all of its existence). By around a billion years from now, it will be so hot and bright that it boils all the oceans on Earth – and that will mean the end for life on Earth.

      Because all the water in the oceans will become steam in the atmosphere, it will increase the pressure in the atmosphere, which increases its temperature (in addition to water vapour being a “greenhouse gas” that also traps heat there). So for the last four billion years of our planet’s life, before the Sun expands to become a red giant, the Earth will become like Venus is today – with a thick atmosphere that is incredibly hot at the surface. Right now it’s hot enough to melt lead on the surface of Venus – and that’s just because of the pressure of its thick atmosphere, because Venus is only slightly closer to the Sun than we are.

    • Photo: Zoe Duck

      Zoe Duck answered on 21 Jun 2010:

      There are many theories for this one. The one that has the most evidence to support it is the expansion of the sun. The sun is currently burning hydrogen to generate heat and light that we feel on the earth. Eventually (a few billion years) the sun will run out of hydrogen and start burning heavier gases such as helium. This will cause the sun to expand swallowing up Mercury and Venus and possibly earth. If it doesn’t swallow the earth it is quite likely to have some effect on its orbit and chemical composition

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