This is Scientific American's 60-Second Space. I'm John Matson. Got a minute?
Since that meteor streaked through Russian skies on February 15th a lot of people have been thinking about asteroid defense.
If an inbound space rock were discovered early enough, a spacecraft could divert it any number of ways:
by nuking it, smashing into it or tugging it off course.
Then there's an idea advocated by aerospace engineer David Hyland of Texas A&M University:
just spray a coat of paint on the asteroid and let the sun do the rest.
The proposal relies on the so-called Yarkovsky effect.
The hottest part of an asteroid--where it's afternoon, asteroid local time--radiates the most heat into space,
and those thermal photons impart a gentle recoil force.
It's incredibly subtle, but it's constant,
so the Yarkovsky effect can significantly change an asteroid's orbit over time.
A new study in the journal Icarus identifies more than 20 asteroids that have been noticeably shifted by the Yarkovsky effect, naturally.
Paint would enhance or reduce the effect by changing an inbound asteroid's reflectance, thereby steering it away from us.
Currently no asteroids that we know of present a real threat to Earth.
But it's good to be prepared.
Ask the dinosaurs.
Thanks for the minute, for Scientific American's 60-Second Space. I'm John Matson.