Need to divert a killer asteroid? Paint it

That's one idea considered for asteroid protection

TUCSON, Ariz. - Here's something to put your day in perspective: Things may not be great but at least we're not about to be hit by an asteroid.

University of Arizona scientists have joined others around the world looking for ways to repel that sort of killer rock, and one idea involves something you'd buy at a hardware store.

Movies love the idea of nuking an incoming asteroid.   But you may not need something that drastic.

One way to nudge as asteroid safely away from us could be as simple as paint in space.

Making a space rock absorb heat differently could change its flight path.

For a quick demo we measured the heat on some dark, sun-baked pavement.  The temp was about 140 degrees.  When we made the same spot more reflective with some white paper the temperature dropped about 30 degrees.

University of Arizona astronomer Carl Hergenrother says if you change the thermal properties of an asteroid,  “That's enough to actually push an asteroid by a small amount but over decades or centuries that's enough to actually move it so it would prevent an impact."

Hergenrother is with University of Arizona's Osiris Rex mission.  It will visit an asteroid and bring back a sample. But Osiris Rex will do more than sample.  It will study the mass and gravity of the asteroid Bennu to learn more about how to nudge an asteroid away from a path to Earth.

Looking at a small meteorite Hergenrother says, “Say this is your asteroid in space and you want to change its orbit you want to hit it kind of centrally.  If you want to change its rotation rate which is another way you can change how the thermal forces are affecting it, say it's spinning this way you want to hit it on the edge to give it that extra oomph."

Scientists wouldn't have to use paint to change how an asteroid heats or cools.  Applying something like light colored rock might work.

But some situations might need something as powerful as the nukes that play so well in the movies.

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