How far is a second?
The moon may be 1.3 light-seconds away, but why on earth do we measure distances using time? minutephysics is now on Google+ - http://bit.ly/qzEwc6 And facebook - http://facebook.com/minutephy...
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You may have heard physicists describe the moon as being 1.3 light-seconds away, or thesun as 8 light-minutes away, and thought "what is this nonsense? measuring distances withtime?"But actually, we measure distances using time almost every day. How far is it from yourhouse to the store? About ten minutes. And how far is it from New York to Boston? Aboutfour hours. Los Angeles to Sydney? 14 hours.But of course, what we really mean is that the store is ten bike-minutes from your house,New York is 4 car-hours from Boston, and Sydney is 14 plane-hours from LA. In fact, usingtime to measure distances is so useful that I only know the distance from LA to Sydneyin plane-hours, not miles or kilometers… though I suppose I could figure it out bymultiplying...
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You may have heard physicists describe the moon as being 1.3 light-seconds away, or thesun as 8 light-minutes away, and thought "what is this nonsense? measuring distances withtime?"But actually, we measure distances using time almost every day. How far is it from yourhouse to the store? About ten minutes. And how far is it from New York to Boston? Aboutfour hours. Los Angeles to Sydney? 14 hours.But of course, what we really mean is that the store is ten bike-minutes from your house,New York is 4 car-hours from Boston, and Sydney is 14 plane-hours from LA. In fact, usingtime to measure distances is so useful that I only know the distance from LA to Sydneyin plane-hours, not miles or kilometers… though I suppose I could figure it out bymultiplying...
