• Question: In how many light years will the sun die? And could we find another solar system with very similar conditions?

    Asked by anon-220623 on 12 Jun 2019.
    • Photo: Rebecca Moon

      Rebecca Moon answered on 12 Jun 2019:


      Unfortunately I am a medical doctor and so my knowledge on space is pretty limited – in fact the only thing I really know is that astronauts lose bone strength when they are in space because they do not participate in any weight bearing physical activity as there is no gravity. This is one of the reasons how we know weight bearing physical activity is so important for bone health.

      I think there is a space zone chat board going on at the same time as this one so maybe pop your question on there and one of their experts will be able to give you a good answer I’m sure. Or maybe someone else on this board will have a space interest outside of their work and be able to help you out! Or if all else fails, try good old google!

    • Photo: Marianne King

      Marianne King answered on 13 Jun 2019:


      Scientists think that our Sun has around 5 billion years left before it turns into a red giant. This will engulf Earth, though life on Earth would be dead long before this happens. After a red giant it will become a white dwarf, which is the core of the star. They’re extremely hot and take billions of years to cool down to become a brown dwarf. It takes so long for them to cool down that it’ll take longer than the current age of the Universe! I believe there must be some other planet out there that could sustain life, but we don’t seem very close to finding it! Maybe way way into the future humans will manage it.

    • Photo: Kaitlin Wade

      Kaitlin Wade answered on 13 Jun 2019:


      The sun has used up about half of its hydrogen fuel since its birth (approximately 4.6 billions years). It still has enough hydrogen to last about another 5 billion years, which is great for us. Once the hydrogen burns out, the sun will explode and become what is called a red giant. As red giants are anything from 100 to 1000 times the size of the sun, it’ll likely engulf the inner planets, possibly even Earth (not so good for us). It’ll stay that way for a couple of thousand to even a billion years then the helium it’s using for energy will burn out and the sun will shrink again into a white dwarf.

      The interesting thing is that, scientists are still debating and researching whether the Earth will be engulfed by the sun when it becomes a red star. Even if it didn’t, we’d be far too close to exist as we know. So, we might not need to find a new solar system, we might be able to exist in one of the other rock planets in our own solar system that has therefore become more habitable with the changing of the sun. But I don’t think it’s completely implausible to think that there are solar systems (maybe younger or older than ours) that have similar conditions to what we live in now. We’d just have to make sure that we have the technology to get there in the first place, which may take time, and travelling there might take a long time too!

    • Photo: Nina Rzechorzek

      Nina Rzechorzek answered on 14 Jun 2019:


      This simply explains how we estimated the Sun’s age and therefore how long we think it has left:
      https://spaceplace.nasa.gov/sun-age/en/
      I imagine that if we are still around when this Sun is dying, we will have already reached a point where (a) we don’t need it or (b) we have replaced it with something else or (c) we have found somewhere else that’s better suited to our species. Trying to be ‘glass half full’ about this. I am certainly not an expert on space.

    • Photo: Matthew Bareford

      Matthew Bareford answered on 20 Jun 2019:


      As with Kaitlins Answer, the sun has about 5 billion years left, and will become a red giant.

      Other Rocky worlds within our own solar system are now thought to be possible alternatives to live on, such as the moons around Saturn and Jupiter. One of these is Titan, which has an atmosphere and water ice on its surface. Once it is warmed by the expanded sun, this ice might melt and become water much like on earth with the rocky moon then able to develop life. Unfortunately this will all take time much longer than we would have.. but it is a nice thought that the end of our planet could mean the start of another..

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