How to protect Earth from potentially hazardous asteroids

Analysis of one of the most infamous near-Earth asteroids has allowed scientists to discover how best to protect Earth from a potential impact.
Researchers studied the near-Earth asteroid 1950 DA and discovered that the body, which rotates so quickly it defies gravity, is held together by cohesive forces, called van der Waals, never before detected on an asteroid.
The findings have potential implications for defending our planet from a massive asteroid impact, researchers said.
Previous research has shown that asteroids are loose piles of rubble held together by gravity and friction. However, the University of Tennessee in Knoxville team found that 1950 DA is spinning so quickly that it defies these forces.

Researchers wanted to know what keeps the body from breaking apart.
Looking at thermal images and orbital drift to calculate thermal inertia and bulk density, the team detected the action of cohesive forces in an environment with little gravity.

"We found that 1950 DA is rotating faster than the breakup limit for its density," said Ben Rozitis, a postdoctoral researcher.
"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," Rozitis said.
In fact, the rotation is so fast that at its equator, 1950 DA effectively experiences negative gravity. If an astronaut were to attempt to stand on this surface, they would fly off into space unless they were somehow anchored.

The presence of cohesive forces has been predicted in small asteroids, but definitive evidence has never been seen before.
The finding provides important information for efforts aimed at stopping an asteroid from crashing into Earth.
"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," said Rozitis.
This research shows some potential techniques, such as a kinetic impactor which would deploy a massive object on a collision course with the asteroid, could exacerbate the impact's effects.

The study was published in the journal Nature.