A U.S. scientist has proposed a novel way of deflecting a possible asteroid from hitting Earth - pelting it with paintballs.
A graduate student from the Massachusetts Institute of Technology proposed the idea, winning this year's annual "Move an Asteroid Technical Paper Competition" sponsored by the United Nations.
Sung Wook Paek says launching paintballs from space would not only cause a force that could push an asteroid slightly off course, but would also coat the asteroid's surface with light paint. The light color would change the amount of sunlight the asteroid reflects, helping to nudge it further off course.
Scientists have proposed a wide variety of methods to avoid an asteroid collision with Earth, including detonating a nuclear bomb near an asteroid or launching a projectile to collide with it.
In his proposal, Paek uses as a test case the asteroid Apophis, which is due to come close to Earth in 2029 and again in 2036. He says five tons of paint would be required to cover the 27-gigaton rock with a fine coat.
Paek's proposal would require a lengthy planning process, as he estimates it would take up to 20 years for the cumulative effect of solar radiation pressure to significantly knock an asteroid off its course.
He also suggests another use for painting asteroids, saying it could help scientists to more easily track them with telescopes on Earth.