• Question: whats a light year ??

    Asked by tashaaaa13 to Keith on 16 Jun 2010 in Categories: .
    • Photo: Keith Brain

      Keith Brain answered on 16 Jun 2010:

      Its the distance that light travels in a year. I could look it up, but its more fun to think …

      I know that the speed of light is about 3×10^8 m/s, so all I need to know now is how many seconds there are in a year … that’s 60s/min * 60min/hour * 24hours/day * 365 days/year, so its about

      3×10^8 m/s * 60s/min * 60min/hour * 24hours/day * 365 days/year = 9.4608×10^15m = 9.4608×10^12 km, or about 10^13 km, which is:

      10,000,000,000,000 km.

      So, quite a long way – about a quarter of the way to the nearest star.

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