Royal Observatory Greenwich explains how the movement of the earth can be used to calculate the distance of the stars away from our little blue dot.
All well and done but stars which are even larger distances away from us, however, do not seem to move at all – so how do we work out how far away they are? This is where objects known as Standard Candles come in to the equation – as we know their luminosity they can be used to measure distances. Still puzzled? Then take a look at this video from the micro exhibition Measuring the Universe: from the transit of Venus to the edge of the cosmos which is at the Royal Observatory Greenwich right now. If you are in London then go see it - it’s on from 1 March–2 September 2012 and its absolutely FREE!
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