• Question: How big do you think a star is?

    Asked by arianarose3 to Ed, Katie, Sam, Steve, Vera on 21 Jun 2011.
    • Photo: Sam Tazzyman

      Sam Tazzyman answered on 21 Jun 2011:

      I think there is quite a lot of variation in how big stars are – you get big ones and small ones. I think that the Sun is quite a small star. However, I don’t know for certain – anyone else?

    • Photo: Katie Marriott

      Katie Marriott answered on 21 Jun 2011:

      Yup I think that correct. Starts expand the older they get until they rach a certain size and then they collapse. So the size of a star depends on how old it is!

    • Photo: Vera Weisbecker

      Vera Weisbecker answered on 21 Jun 2011:

      Like Sam and Katie said. The stars get categorized into different types – you get red giants and white dwarfs etc, and their sizes differ by orders of magnitude.

    • Photo: Steven Daly

      Steven Daly answered on 21 Jun 2011:

      Stars have to be able to be big enough to start nuclear fusion, which sets a lower limit on their size. If we are including neutron stars (which are the leftovers of an exploded star), then stars can be anything from 20km to about 900,000,000 km in diameter. For comparison the earth is about 12,800 km in diameter. Stars are really really big!

    • Photo: Ed Morrison

      Ed Morrison answered on 21 Jun 2011:

      Stars can also become really really small. When they get too big, they can collape in on themselves (neutron stars I think) under the influence of gravity, until they’re just a few miles across. Then they can form black holes which suck matter and light into them. I’m not an expert on this though.

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