Massive, Gravity-Defying Asteroid May Reveal Forces that Could Protect Earth from Future Collisions

Scientists may have just made a discovery that could protect our planet from future collisions with asteroids. They've studied the near-Earth asteroid 1950 DA and have found that the rocky body, which rotates extremely quickly, is held together by forces called van der Waals, something that has never before been detected on an asteroid.

Normally, asteroids are loose piles of rubble that are held together by gravity and friction alone. Yet 1950 DA spins so quickly that it seems to defy these particular forces. That's why scientists decided to take a closer look at this asteroid to find out why it simply didn't break apart.

The researchers examined thermal images and orbital drift in order to calculate thermal inertia and bulk density. In the end, they detected the action of cohesive forces in an environment with little gravity. In fact, the rotation is so fast that at its equator, the asteroid effectively experiences negative gravity. This means that if an astronaut were to land on the surface of the asteroid, he would fly off into space unless he was somehow anchored.

"We found that 1950 DA is rotating faster than the breakup limit for its density," said Ben Rozitis, one of the researchers, in a news release. "So if just gravity were holding this rubble pile together, as is generally assumed, it would fly apart. Therefore, interparticle cohesive forces must be holding it together."

So how would this protect Earth from asteroid impacts? It shows what potential techniques could deflect an asteroid if one was headed toward Earth-and what techniques not to use. For example, if a kinector impactor deployed a massive object on a collision course with the asteroid, then this impactor could simply break apart the asteroid into several threatening chunks headed toward Earth. Essentially, it would exacerbate the problem.

"Following the February 2013 asteroid impact in Chelyabinsk, Russia, there is renewed interest in figuring out how to deal with the potential hazard of an asteroid impact," said Rozitis. "Understanding what holds these asteroids together can inform strategies to guard against future impacts."

The findings are published in the journal Nature.