Asteroid Bennu, a space rock the size of the Empire State Building, is expected to fly by close to Earth in 2135.
Asteroid Impact Effects
Scientists said that the chances of the asteroid colliding with Earth are slim, but if such impact would happen, its effects could be devastating, as Bennu could generate force 80,000 times more powerful than the nuclear weapon dropped on Hiroshima, Japan during the final stage of World War 2.
"Because it passed within half an Astronomical Unit (AU) from Earth, it is listed among the potentially hazardous asteroids (PHAs)," NASA said.
Protecting Earth From An Asteroid Impact
NASA and Russian scientists are already making plans and conducting experiments to protect Earth from an asteroid impact. Russians are now zapping mini asteroids in the laboratory, and NASA mulls on nuking the space rock.
It appears though that there are other less destructive options to save Earth from an incoming asteroid. Scientists, for instance, could alter the path of the space rock by painting its surface.
Using Paint To Alter Path Of Asteroids
NASA's OSIRIS-REx Flight Dynamics System Manager Michael Moreau said that just painting the asteroid's surface with a different color on one side can change the thermal property of the space rock and change its orbit. A spacecraft could be sent to change the color of some asteroids that pose threats to our planet.
The sun continuously bombards everything in the solar system with solar particles. These tiny particles do not have significant impact on objects as massive as Earth. Asteroid Bennu, however, is only 13 times as massive as the Great Pyramid of Giza, which is relatively light.
Scientists can influence Bennu's orbit by giving solar radiation better chances of pushing the space rock away from Earth. One way of doing this is to paint one side of the asteroid a different color, which could make a difference on the amount of radiation that the asteroid absorbs. More radiation means more pressure can be exerted to divert the near-Earth object.
The idea of painting a potentially dangerous asteroids has been around for a while. In 2012, MIT graduate student Sung Wook Paek proposed firing pellets full of white paint powder at asteroids on a collision course with Earth.
Paek said that the initial force from the paintballs would help nudge the space rock slightly off course, and the paint job from the splattered pellets can double the asteroid's sunlight reflectivity. He suggested that the increased amount of photons bouncing off the space rock's surface could enhance solar radiation pressure and bump the asteroid further off course.
The idea won the 2012 Move an Asteroid Technical Paper Competition.