LOS ANGELES, CA (Catholic Online) - How would you do it? Would you send a motley crew of old, washed-up astronauts and wildcats to bury a nuke deep inside its core, or would you rush a few lucky survivors into secret bunkers to wait out the calamity?

Hollywood's had its say, but according to scientists, those might not be the best approaches. Indeed, the scientific approach could be as simple as "tagging" the asteroid.

Tagging is the slang term for spray painting graffiti onto the walls of public spaces. How interesting then, to see it suggested as a means of saving the planet from destruction. Despite the amusing connection however, the idea is based on sound scientific principles.

A phenomenon known as the Yarkovsky effect, says that as an object heats up in space, the side which is heated acts like a miniature rocket, naturally propelling objects away from the sun, albeit very slightly. A similar effect is seen in a Crooke's radiometer, or light mill. A light mill is made of an airtight bulb with vanes mounted on a spindle. Panels on the vanes are painted white and black and when exposed to sunlight, they spin. Note that this is not the same principle at work, but merely an illustration.

In the same vein, merely painting an asteroid white would cause its orbit to change. Not only would the paint itself add mass to the object, but the Yarkovsky effect would cause the object to be pushed slightly away from the sun. Although the force is slight, it would be constant and over long periods of time, it would move the object into a new, safer orbit.

Unfortunately for our team of intrepid taggers who would be sent to paint the asteroid white, spray paint won't do the trick. The nature of space would actually cause the particles of paint to evaporate without sticking to anything. Instead, an unmanned probe would probably be sent to spray the surface of the killer rock with an electrically charged powder, which would stick quite well.

This approach would not work if the asteroid were likely to hit the Earth within a short time span, such as months to days. In all cases, it would need several years to be effective. However, with improved detection techniques, we should have the lead time we require.

Asteroid 2012 DA14 is nature's warning shot across our bow. Larger rocks have hit, such as the one that killed the dinosaurs some 66 million years ago. A similarly sized rock caused the Tunguska event in Siberia in 1908. If Asteroid 2012 DA14 were to strike the Earth someday, it would not likely cause a catastrophe, especially if it fell in an uninhabited region. However, nature has made clear that larger rocks are out there, and some are genuine planet killers.

If we wish to avoid the fate of the dinosaurs, then we must keep an eye on the heavens and, we suppose, a can of paint handy.

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