The brilliant xkcd addressed the urgent question “what if everyone in the world got together in one place and jumped at the same time?”
He posited a gathering of the world’s population in Rhode Island – which he claims is the perfect size to contain 7 billion folks who weigh on average 50 kg – and confirmed the findings of ScienceBlogs and Straight Dope, reassuring us that the earth’s recoil would be insignificant and that our planet would NOT be thrust noticeably out of its usual orbit. Mainly due to the fact that the earth outweighs the human population by a factor close to 20 trillion.
However, xkcd did not take his thought experiment a logical step further to ask: “what if everyone in the world were BALLET DANCERS and they all got together in Rhode Island and jumped at the same time?”
(Those of you who have taken Ballet to the People‘s class and suffered through her foot articulation exercises will see where this is headed…)
Assuming we had a pianist who could play loud enough for all 7 billion dancers to hear, and assuming they all plié-d on the downbeat, we could get everyone to take off and land at precisely the same moment, ON THE TIPS OF THEIR TOES, then articulate through the metatarsus down to the heel. And let’s say these were Intermediate Level dancers who could manage this landing ON ONE FOOT. At that first moment of re-entry, when the tips of the toes make contact with the earth, the entire weight of each body is concentrated within a teentsy area at most 2-3 cm in diameter, creating a force considerably more powerful than, say, a basketball player in size 15 Nike Airs who lands pretty close to flat-footed, thereby distributing his weight over an area at least 10 times that of the ballet dancer.
Who is hitting the ground with more force? ...the assassin Kobe?
...or the daredevil Osipova?
Will 7 billion dancers landing with 10 times the force originally envisioned by xkcd create enough impact to shove the earth out of its usual orbit?
Probably not.
But… THEY’D MAKE A HELLUVA LOT LESS NOISE ON LANDING.
Which is why, during allegro, we keep saying: “land toe-ball-heel!”
