Harlem shaking. Everyone's doing it, it's terrible, and sometimes you wish they would die. Lately, it seems like they might. Passengers on one plane nearly sparked an aviation emergency after harlem shaking en masse without thinking about the physics of such concerted action:
Maybe it seemed like a good idea at the time, but the problem is that a plane is, y'know, a floating tube hurtling through the air at hundreds of miles per hour. Everyone in that floating tube violently throwing their weight around runs quite a high chance of upsetting the delicate balance that keeps the tube floating in the air.
As a result, the FAA is looking into whether the stunt, which was carried out by students from the Colarado College in the US, was safe. The *Catalyst*, the college's newspaper, reports :
The students, who were traveling from Colorado Springs to San Diego on the way to an ultimate frisbee tournament, filmed a version of the “Harlem Shake,” a YouTube meme that has gone viral in the past few months. While no charges or sanctions have been filed against the airline or the students, the FAA is continuing their investigation into the flight and working to uncover if any regulations were violated.
“They are still looking into it, it’s still open,” Tony Molinero, a spokesman for the FAA said this week. “…I don’t know where the [investigators] were told about it, but when they saw the video they just decided to look into it because it is better to be safe than sorry.”
Back-of-the-envelope maths shows that the shakers would have to try quite hard to kill themselves. Take a Boeing 727-100, roughly the same type of plane the shakers will have been on. That plane has a maximum takeoff weight of 77 tonnes, and an empty weight of just under 37 tonnes. That means that, assuming the airline is halfway competent, the total weight of everybody on board can't be more than 40 tonnes. As it’s is, of course, they are likely to be nowhere near that. For one thing, much of that weight will actually be luggage and other essentials; for another, the plane holds a max of 150 passengers, and even assuming some bulky American football players, they don't weigh an average of 375kg.
So assume, at a stretch, a passenger weight of around 20 tonnes — maybe there are some really fat people just off frame. And assume that, at some point in the shake, they all threw their weight in the same direction at the same time. That would also be unlikely, given the whole point of the Harlem shake is everyone shaking crazily, not moving in lockstep as though they were inmates at that Thai prison where everyone is forced to dance to Michael Jackson.
A professional long-jumper hits 10m/s  at the end of their run, so again, being generous, lets assume that's the speed our airborne meme-generators throw themselves to the side. If they make up roughly a quarter of the weight of the plane, that means the jet as a whole will lurch 2.5 m/s to the side.
That's about the magnitude of a particularly nasty stretch of turbulence. The far more dangerous aspect would be the fact that if you have 150 people in a confined space throwing themselves against the wall, the resulting crush would leave several of them gasping for breath.
And in the real world, the Harlem shake doesn't involve everyone throwing themselves in one direction in an effort to take down a plane. Instead, it just involves someone dancing like a tit for fifteen seconds, before everyone else dances like a tit for a further fifteen seconds. In those circumstances, they'll likely land safe and sound. Though frankly, they don't deserve to.