• Question: Which is the oldest and youngest planet in the Solar System ?

    Asked by josielouise to Davie, Gemma, James P, James V, Nuala on 26 Jun 2012.
    • Photo: James Verdon

      James Verdon answered on 26 Jun 2012:


      Hi josielouise,
      I’m not sure, but I think that most of the planets have fairly similar ages. Once the sun had formed, there was a small amount of left over stuff orbiting around it (something like 95% of the solar system, is the sun – all the planets, even Jupiter, really are tiny left-overs in comparison). This left over material would have been bumping around against each other as it orbited.

      Gradually, to force of gravity, which attracts all matter to itself, would have made everything tend to clump together. In the end, there were 8 planets (plus little Pluto) that clumped together, as well as countless smaller asteroids and other things. So this means that they all formed at pretty much the same time. Radiometric dating tells us that the Earth, and every other planet, formed about 4.5 billion years ago!

    • Photo: James Pope

      James Pope answered on 26 Jun 2012:


      Hi josielouise,

      I think that all the planets in the solar system are about the same age at around 4.5 billion years old. Once the sun formed and had enough mass to develop it’s gravitational field then the planets (both solid and gaseous) could form in their orbits.

    • Photo: Nuala Carson

      Nuala Carson answered on 26 Jun 2012:


      Hey josielouise,

      Yeah i’m not too sure about this one. I would assume they are all the same age (as James P and James V both said). All the plants were formed around the time of the big bang. Some may be older/ younger if the small lumps of debris from the big bang took different amounts of time to join together to form the planet but in the grand scheme of things I don’t think it would be that much.

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