The force that holds asteroids together and the force that allows geckos to cling to surfaces may be one and the same.
What do asteroids and geckos have in common? Not a lot, as you’d expect, but they may share a common force.
This rather strange notion comes from research being done by a team of University of Colorado scientists who have been studying the odd nature of the asteroid Itokawa. When the Japanese Hayabusa mission visited the space rock in 2005 (Hayabusa’s sample return capsule is set to return to Earth on June 13th by the way), it noticed the asteroid was composed of smaller bits of rubble, rather than one solid chunk. Although this isn’t a surprise in itself — indeed, many asteroids are believed to be floating “rubble piles” — the rate of spin of the asteroid posed a problem.
Itokawa spins rather fast and if only the force of gravity was keeping the lumps of rock together, they would have been flung out into space long ago. In short, the asteroid shouldn’t exist.
Although plenty of theories have been bandied around, one idea seems to stick.
More commonly found as a force that holds molecules together, the van der Waals force may bind the individual components of the asteroid together, acting against the centripetal force caused by its spin.
But where do the geckos come in?