No, a Huge Asteroid Is Not “Set To Wipe Out Life On Earth In 2880″

An anonymous reader writes "Phil Plait wants you to know that asteroid 1950 DA is very, very unlikely to hit the Earth in 2880, despite what you may have read. He writes: "As it happens, 1950 DA is what’s called a ‘near-Earth asteroid’, because its orbit sometimes brings it relatively close to Earth. I’ll note that I mean close on a cosmic scale. Looking over the next few decades, a typical pass is tens of millions of kilometers away, with some as close as five million kilometers — which is still more than ten times farther away than the Moon! Still, that’s in our neighborhood, which is one of the reasons this asteroid is studied so well. It gets close enough that we can get a decent look at it when it passes. Can it impact the Earth? Yes, kindof. Right now, the orbit of the asteroid doesn’t bring it close enough to hit us. But there are forces acting on asteroids over time that subtly change their orbits; one of them is called the YORP effect, a weak force that arises due to the way the asteroid spins and radiates away heat. The infrared photons it emits when it’s warm carry away a teeny tiny bit of momentum, and they act pretty much like an incredibly low-thrust rocket. Over many years, this can change both the rotation of the asteroid as well as the shape of its orbit."

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