• Question: how many planets are there?

    Asked by connornffc to Anne, Carolyn, Joe, Mariana, Nick on 16 Mar 2010 in Categories: .
    • Photo: Nick Bradshaw

      Nick Bradshaw answered on 16 Mar 2010:

      In our solar system there are eight proper planets, plus several “dwarf” planets (which includes Pluto) and lots of astroids. However there are trillians of other stars out there in the universe, so there are going to be lots more planets around all of those!

    • Photo: Joseph Devlin

      Joseph Devlin answered on 16 Mar 2010:

      No one knows but almost certainly many billions (and that’s probably a very low guess). Up until 1995, we only knew for sure about the 8 planets in our solar system (at the time, Pluto was still considered a planet so there were actually 9 then). But in 1995, the first extra-solar planet was discovered. As of earlier this year, there are 431 extra-solar planets and new ones are being discovered all the time.

    • Photo: Carolyn McGettigan

      Carolyn McGettigan answered on 16 Mar 2010:

      In our solar system, there are eight main planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn and Neptune. Poor old Pluto used to be a main planet but got downgraded to ‘dwarf planet’ a couple of years ago. So my childhood textbooks are out of date…

      Just had a look on the web and the other dwarf planets in our Solar System are called Ceres, Haumea, Makemake and Eris. That’s news to me – learnt something today!

      Of course, because there are lots of solar systems in our galaxy, and lots of galaxies beyond ours, the total number of planets around must be very, very big.

    • Photo: Mariana Vargas

      Mariana Vargas answered on 16 Mar 2010:

      I’m not an astronomer.. but my husband is! And he says that there are 8 planets in our solar system (not counting Pluto anymore). We also know about several hundred “extra-solar” planets, which are planets going around other stars. And, there are literally billions and billions of other planets – too many to count – that we haven’t observed yet but we think should be there, going around stars both in this galaxy and in all the other galaxies in the universe.

    • Photo: Anne Seawright

      Anne Seawright answered on 18 Mar 2010:

      When I was at school there were 9 in our solar system but now I believe there are 8!

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