• Question: when will the sun die and are humans still alive at that time?

    Asked by 07quiambaoj to Alastair, Emma, Hywel, Keith, Vicki on 18 Jun 2010 in Categories: .
    • Photo: Keith Brain

      Keith Brain answered on 18 Jun 2010:

      The wiki page on “Stellar Evolution” has a nice graphic showing the predicted life cycle of the sun:


      So, we have about 5 billion years to go.

      Our species has changed a lot in the last 100,000 years, so given the opportunity to evolve at the same rate, we should have 50,000 such “changes” over the course of 5 billion years (ie. 5,000,000,000/100,000). So, our distant descendants, if any survive that long, will be very different from us. Hopefully they will be more clever, and will have had more time to work out how to get to another solar system and live there sustainably. There should be more than enough time for that.

    • Photo: Alastair Sloan

      Alastair Sloan answered on 18 Jun 2010:

      Ok, am no expert here, but I think the sun is about 4 billion years old and as its energy is nuclear fusion it contains lots of hydrogen. The sun will die when it runs out of hydrogen and astronomers think that will be in about 5 billion years time. When it runs out of hydrogen the sun will start to die and become a red giant. It will also get larger in size and the Earth will be burnt to a crsip. If humans are alive at this point they need to be nowhere near the Earth. In fact nowhere near the solar system!

      In simple terms the answer is – no for some considerable time!

    • Photo: Vicki Stevenson

      Vicki Stevenson answered on 18 Jun 2010:

      there is enough fuel in the sun for it to burn for about five billion years – when it runs out of fuel it will swell up and swallow the earth.
      Will there still be humans? it’s hard to say – it’s less than 5000 years since the pyramids were made so the entirety of human history so far is a blink in comparison to the amount of time left to the sun.

    • Photo: Emma Carter

      Emma Carter answered on 18 Jun 2010:

      I have no idea on either of those. But as far as I am aware there aren’t any signs of the sun dying any time soon – we’ve probably got thousands of years, by which time we may have worked out how to colonise other solar systems – but that’s all a bit sci fi and I don’t really know