• Question: How many 30cm rulers will it take to get the end of the Galaxy?

    Asked by shmurple to Amy, Drew, Julia, Kimberley, Sara on 15 Jun 2011.
    • Photo: Sara Imari Walker

      Sara Imari Walker answered on 14 Jun 2011:

      Hi shmurple. This is an interesting question!! The size of our galaxy is 100,000 light-years across (that means it takes 100,000 years for light to reach us from the far edge of our galaxy!). Using 30cm rulers – thats 3,153,510,000,000,000,000,000 rulers! That’s a lot higher than I can count!! I suppose if we wanted to be lazy we could measure the height of the disk of our galaxy rather than the width – that’s 1,000 light-years across which would knock a few zeros off that estimate 😉

    • Photo: Kimberley Bryon

      Kimberley Bryon answered on 14 Jun 2011:

      Wow, that is a lot of rulers. Thanks for answering this Sara 🙂 I certainly didn’t know the answer to this one

    • Photo: Julia Griffen

      Julia Griffen answered on 14 Jun 2011:


    • Photo: Drew Rae

      Drew Rae answered on 14 Jun 2011:

      Hi. I’m glad Sara worked that out so I didn’t have to! Thank’s Sara!

    • Photo: Amy MacQueen

      Amy MacQueen answered on 15 Jun 2011:

      Do you have this many rulers? I could lend you…eh …two? 🙂