• Question: how do planets form

    Asked by to Kate, Joe, Juan, Rory, Rosie on 17 Mar 2014. This question was also asked by , , .
    • Photo: Kate Salmon

      Kate Salmon answered on 17 Mar 2014:

      Hi @pop112, @rainbow88 and @purplepenguin- planets form after the birth of stars. After stars are born, there is still a lot of rock and debris floating around the outside of the star in a big circular orbit. These bits of rock crash into each other forming asteroids and very small, ancient planets called planetesimals. These planetesimals gradually get bigger (after ~500 million years) because they collide with asteroids and other planetesimals and eventually form planets around the central star.

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