• Question: How will the world end? and why?

    Asked by georgia123 to Jen, Emma, Mona, Michael, Joseph on 14 Jun 2011. This question was also asked by meganpower, antonia123, brittsz, natz, kammy, kendralouiseogdenx, submarine3, jorjia, doncarios, kirstysargeant, lolscientist, joshuapowell, rere.
    • Photo: Michael Taggart

      Michael Taggart answered on 14 Jun 2011:

      I don’t really know, I suspect I won’t be around at the time it happens to maybe get a whiff of what’s going on and am fairly sure other zone buddies will have better answers but ….. I’d hazard a guess it will be due to an eventual depletion of the energetic sources that keep the matter that we know as earth in its’ present equilibrium.

    • Photo: Jen Gupta

      Jen Gupta answered on 14 Jun 2011:

      As an astronomer my answer is slightly different to Michael. There are two astronomical events that will happen in the distant future and one of them will probably mean the destruction of the Earth.

      First, our galaxy the Milky Way is on a collision course with the nearest spiral galaxy, which is called Andromeda or M31. It’s thought that the two galaxies will first collide in about 2 billion years but then pass through each other before being pulled back again. This will happen a few times until the two galaxies merge together and form an elliptical galaxy. There are some cool videos on youtube that show simulations of this happening, and a good example of two spiral galaxies merging together is called The Mice (eg http://apod.nasa.gov/apod/ap020506.html). Now nobody quite knows what will happen to the Sun in this process. Stars in galaxies are relatively spread out so it’s unlikely that our Sun will collide with another star. However it is possible that the Sun will be flung out into another part of our galaxy, flung out of our galaxy or even become part of Andromeda while the galaxies are making their passes. I guess that the solar system, including the Earth, will stay orbiting around the Sun. So chances are that the Earth will survive this process but it could be destroyed.

      The second event that will almost definitely mean the end of the Earth is the Sun dying. The Sun works by fusing together hydrogen atoms to make helium. This process produces energy. However the Sun only had a limited supply of hydrogen so eventually it will use up all of its fuel. It will then expand and become a red giant star. Estimates of when this will happen tend to be in around 5 billion years. When the Sun become a red giant, it will become so big that it will probably extend out to the orbit of the Earth! So we would be within the Sun and probably be destroyed!

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