• Question: what is the biggest planet?

    Asked by victoria & jake to Simon, Julia, Delma, Andrew, Alex on 14 Dec 2015.
    • Photo: Simon Challis

      Simon Challis answered on 14 Dec 2015:

      Hi Victoria and Jake!

      In the Solar System this would be Jupiter (famous for its gasclouds, red spot and moons!). Jupiter is about 11 times bigger than Earth. However if you consider all the planets that have been discovered so far (not only around our Sun), the current record holder goes to HAT-P-32b in the constellation of Andromeda. Its about a 1000 light years from Earth and is about twice the size of Jupiter! This is probably about as big as a planet can get before it becomes a star since it would then be so massive that it collapses in on itself and nuclear fussion naturally occurs (which is how all stars are born!).

      In fact some astronomers in the past have said that Jupiter is essentially a failed Star!

      Of course exoplanets are being discovered so quickly these days that Julia/Delma/Andrew or Alex might actually be able to cite an even bigger planet tomorrow 🙂

    • Photo: Delma Childers

      Delma Childers answered on 15 Dec 2015:

      Simon’s got that right! 😛

      We are always discovering new planets. So far, the largest ‘exoplanet’ (planet outside of our solar system) is DENIS-P J082303.1-491201 b. It’s about 13 times larger than Jupiter (around 145 times larger than Earth). It is possible it might actually be a brown dwarf (a kind of star) instead of a planet, though. 🙂

    • Photo: Andrew Winnard

      Andrew Winnard answered on 15 Dec 2015:

      Here are some cool facts about Jupiter!