how do scientists know stars are millions of light years away??? have they been there and back , do they have a tape measure that strechs that long????
how do scientists know stars are millions of light years away??? have they been there and back , do they have a tape
Posted on March 9, 2013 by in Question. Comments Off on how do scientists know stars are millions of light years away??? have they been there and back , do they have a tape
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