Carl Sagan wrote in his book Cosmos that there are more stars in the universe than all the sand grains on Earth. You still hear this from time to time; it’s one of those astronomy clichés that never goes away. It’s an awe-provoking image that captures the vastness of the cosmos in a way that mere numbers cannot.
Except it isn’t true.
I set out to tackle this more than 20 years ago, during my 16th year with Discover magazine. I initially tried to research the answer, with no luck. You’d think someone would have already attempted to confirm this well-worn cliché, but I had to do it myself.
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