• Question: When the sun reaches the end of its life cycle will it form a white dwarf, a neutron star or a black hole? And will there be a supernova?

    Asked by Maddie to Andrea, Charlie 🚀, Col Op, Kirsty, Vinita on 17 Jun 2016.
    • Photo: Andrea Boyd

      Andrea Boyd answered on 17 Jun 2016:

      We don’t have to worry about this in any of our lifetimes or even our great great great great great great great (add quite a few more greats) grandkids lifetimes thankfully!

      I had to ask some smarter people about this one. Based on what Astrophysicists have observed, the Sun (red giant) will eventually turn into a subred giant (carbon-helium instead of helium-hydrogen) with a white dwarf core and then it spreads out plus burns fuel 100 times as fast as now so it eventually becomes a red giant again but with a massive overall diameter going as far as Jupiter (goodbye half our solar system), and the outer layers move apart and break away. (The sun already dealt with a supernova ages ago and it didn’t affect it much). At this point the sun has lost half it’s mass but the remaining mass is way more dense and looks super white – it’s now a nebula and stays like that for a relatively short time until all the fuel burns out and all that’s left is the core: a white dwarf.

      If the final white dwarf had enough things passing by it could pull in enough mass to collapse into a neutron star.

      If it could take in energy from another active star or another white dwarf, then it could explode into a type of supernova. (the type that burns with a pretty fixed brightness level – these are very very useful in astronomy because, with telescopes like Hubble, Astrophysicists have been able to use them to measure distance in the universe. When the James Webb Space Telescope is launched we should be able to get an even better view of these and the universe!!)

    • Photo: Columbus Operations

      Columbus Operations answered on 17 Jun 2016:

      Joao: Hi Maddie, great question! The Sun is a relatively small start… or better, it is a medium sized star. The fact is that there are much bigger start in the Universe. And only big start will result in neutron stars, black holes and supernovae. Our Sun is not big enough for that.

      Instead it will start to turn into a red giant, getting bigger and bigger, hotter and hotter. As a red giant, the Sun will grow so large that it will engulf Mercury, Venus, and probably Earth, too.

      But even before it becomes a red giant, the luminosity of the Sun will have nearly doubled, and Earth will be hotter than Venus is today.

      But will only happen in 5.4 billion years. For comparison, the Earth is “only” 4.5 billion years old!

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