Slashdot Mirror
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."
Everything I've read said it's very unlikely to hit Earth in 2880. One chance in three hundred does not "likely" make.
On the other hand, 1 in 300 is pretty close to the chance of a Straight coming up without a Draw....
"I do not agree with what you say, but I will defend to the death your right to say it"
Especially when you compare it to the gravitational changes induces by each pass by the Earth/moon system and its pass of Mars and (more weakly) Jupiter.
Each one affects it FAR more than anything from photon pressure.
Yeah, TFS makes it sound like the YORP effect is something significant, but if you read TFA (I know, i know...) you discover that the YORP thing seems to be there to point out: (1) there are lots of very small effects that make long-term predictions for orbits difficult, and (2) one needs to do a LOT of observations to be able to predict all of these factors, but (3) we HAVE an unusually large set of observations on this asteroid (including enough to predict things like YORP effect factors).
Hence, from TFA:
They accounted for a lot of small effects on the asteroid, including the YORP thrust, the gravity of the planets, the gravity of other asteroids, and so on. They found that the probability of an impact in 2880 is about 2.48 x 10^-4, which is about 1 in 4000.
I realize that lots of people out there are idiots, and everyone here thinks that they can immediately think of something obvious that no expert doing a study would ever consider... but, you know, sometimes the experts actually have thought of the obvious thing before you posted about it on Slashdot.
This asteroid is only around 1 km in diameter. An impact would be distinctly annoying, but civilization, and most people, should survive.
a,e,i,o,u and sometimes w and y (at be if of up cwm by)
Good deal. That means we can ignore this!
SJWs are the new boogeyman. -Me
"The Yarkovsky–O'Keefe–Radzievskii–Paddack effect, or YORP effect for short, is a second-order variation on the Yarkovsky effect that changes the rotation rate of a small body (such as an asteroid)."
http://en.wikipedia.org/wiki/Yorp
We know where leadership by an anti-intellectual "strongman" who scapegoats minorities and likes boisterous rallies goes
Everything I've read said it's very unlikely to hit Earth in 2880. One chance in three hundred does not "likely" make.
Especially since it is actually 1 in 4,000 or 0.0248%. Still I'd actually think it would be a good thing to have the odds a lot higher, like 90%, with a lead time like this of 800+ years. To date the existential threat posed by wars have caused science to make massive advances but this has come at a huge cost of misery and death
Think of the scientific advances that could come from an existential threat that, instead of pitting us against each other, actually puts all of humanity on the same side for a change. In the past 800 years we have come from the dark ages to the internet age. If we can't get it together enough to develop the technology needed to cause a small deflection to an asteroid in the next 800 years then I'd say it was probably time for evolution to give it a second roll of the dice.