• Question: Is there more future or more past?

    Asked by Princess Zolanskii to Hummy, Lewis, James, Sandra on 13 Mar 2017.
    • Photo: Sandra Greive

      Sandra Greive answered on 13 Mar 2017:

      I have no idea. It depends on what time scale you’re thinking, the planet, humans, the universe. All these have begun and might end at different times. Our planet will likely continue to exist long after humans are gone, but I don’t know when that will be. It depends very much on the choices we make as a society today and the impact they might have on our environment. I’m sorry its not a clear answer but when we don’t understand things well, this is the best that we can do. I am talking both about my own understanding and the collective understanding of science in general of the potential impact of human activity on our environment. There is plenty of room for future discoveries in this field.

    • Photo: Lewis Wright

      Lewis Wright answered on 13 Mar 2017:

      This is a fantastic question!

      By looking at how the universe is expanding, we can work backwards to find out when it began. Scientists estimate the universe to be just under 13.8 billion years old. Thats a long time!
      For context the Sun is around 4.5 billion years old (as a mid-sized star midway through its lifecycle), and the Earth was created around the same time (since it needed something to orbit!)

      So how much time do we have in front of us?
      The Sun is expanding as it ages, and a few hundred million years before it explodes it will grow big enough that it will engulf the Earth (and Mercury and Venus). This will happen in 4-5 billion years.
      Assuming humans get off the planet, there is an estimated to be 1000 billion to 100 000 billion (1-100 trillion) years worth of fuel with which stars can form.
      However ‘the end’ will come with the Heat Death of the universe, where everything is so far apart due to an expanding universe that everywhere is the same temperature. Temperature gradients and exchanging energy is, boiled down, how the universe works, so once everything is the same temperature nothing else can happen.
      The Heat Death is predicted to occur in 10^100 years (thats a ‘1’ with 100 ‘0’s after it, AKA a Googol years, one of the largest numbers with a name), however some Black Holes are predicted to last longer than the life of the universe, which is hard for me to get my head around!

      TLDR; there is more future than past.

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