• Question: What is a light year and how long is it?

    Asked by meg123 to Amy, Karen, Sarah, Vijay, Will on 19 Jun 2012.
    • Photo: Will Reynolds

      Will Reynolds answered on 19 Jun 2012:

      Hi Meg. A light-year is a measure of distance used in space. One light-year is the distance light travels in a year. The speed of light is 299, 792, 458 metres per second and there are 31, 556, 926 seconds in a year so a light-year is equal to 9,460,528,412,464,108 metres!

    • Photo: Karen Reed

      Karen Reed answered on 19 Jun 2012:

      Hiya Meg – Will beat me to it on this one 🙂 Can’t top his answer

    • Photo: Sarah Martin

      Sarah Martin answered on 19 Jun 2012:

      Hi meg,

      as Will says, a light year is not a measure of time, but it is the distance that light travels in one year! So it’s a great way to talk about distances really far away in the Universe, because if we stick to kilometers or miles we’ll have to add lots and lots of digits which would be really cumbersome.

      🙂 Sarah

Comments