We've all heard the story. A young Isaac Newton is sitting beneath an apple tree contemplating the mysterious universe. Suddenly - boink! -an apple hits him on the head. "Aha!" he shouts, or perhaps, "Eureka!" In a flash he understands that the very same force that brought the apple crashing toward the ground also keeps the moon falling toward the Earth and the Earth falling toward the sun: gravity.
Or something like that. The apocryphal story is one of the most famous in the history of science and now its origin has come to light. Squirreled away in the archives of London's Royal Society was a manuscript containing the truth about the apple.
The manuscript, from 1752, is a biography of Newton entitled Memoirs of Sir Isaac Newton's Life written by William Stukeley, an archaeologist and one of Newton's first biographers. Newton told the apple story to Stukeley, who relayed it as such:
"After dinner, the weather being warm, we went into the garden and drank thea, under the shade of some apple trees...he told me, he was just in the same situation, as when formerly, the notion of gravitation came into his mind. It was occasion'd by the fall of an apple, as he sat in contemplative mood. Why should that apple always descend perpendicularly to the ground, thought he to himself..."
The Royal Society has made the manuscript available today for the first time in a fully interactive digital form on their website at royalsociety.org/turning-the-pages. The digital release is occurring on the same day as the publication of Seeing Further (HarperPress, £25), an illustrated history of the Royal Society edited by Bill Bryson, which marks the Royal Society's 350th anniversary this year.
So it turns out the apple story is true - for the most part. The apple may not have hit Newton in the head, but I'll still picture it that way. Meanwhile, three and a half centuries and an Albert Einstein later, physicists still don't really understand gravity. We're gonna need a bigger apple.