Neil deGrasse Tyson Outlines a Plan For Saving Earth From Asteroids 241
dsinc contributes a link to Neil deGrasse Tyson's short piece in Wired on how we could deal with the very real threat of killer asteroids, writing "In 2029 we'll be able to know whether, seven years later, Apophis will miss Earth or slam into the Pacific and create a tsunami that will devastate all the coastlines of the Pacific Rim." From the article: "Saving the planet requires commitment. First we have to catalogue every object whose orbit intersects Earth’s, then task our computers with carrying out the calculations necessary to predict a catastrophic collision hundreds or thousands of orbits into the future. Meanwhile, space missions would have to determine in great detail the structure and chemical composition of killer comets and asteroids."
Re:When exactly (Score:5, Informative)
The Colbert interview was awesome. He apparently gave a hard time to James Cameron because the night sky in Titanic was historically inaccurate and when Cameron did the director's cut a while later he asked Tyson to provide the sky.. and he did.
Yes, it did, 12,900 years ago (Score:5, Informative)
Evidence for Younger Dryas impact: http://www.pnas.org/content/early/2012/03/01/1110614109.abstract [pnas.org]
Note that the YD debris layer covers 10% of the Earth. It is hypothesized it was caused by a comet which broke up some time before hitting Earth, so created a large number of smaller craters rather than one big one.
Re:An asteroid impact is survivable on earth (Score:4, Informative)
I would add that what killed all the dinosaurs was not the asteroid impact itself, but the asteroid winter that caused a collapse of the food chain. The asteroid blast and fire ball and tsunami was localized, it killed dinosaurs locally but its not what killed them off globally, the blockage of the sun did. If enough food can be stored away to get through the winter and then seeds to immediately restart agriculture when things clear, humans can survive it.
Re:Then a butterfly flaps its wings (Score:2, Informative)
This is no joke.
Yes it is. Orbits, unlike the weather, are not chaotic. For those who don't know, chaotic means "sensitively dependent on initial conditions", which in practice means that the error in your output calculation is not proportional to the error in your measurement of the initial state. This is why accurate, non-probabilistic weather predictions will never be possible beyond the very short term.
Orbits are not chaotic. The error in the calculation of the orbit is proportional to the error in our current measurements of its position and velocity, and any relevant masses that could affect its orbit. The more we study the object, the more precisely we know its orbit, and the more precisely and the farther into the future we can predict its orbit.
We don't need to solve the 3000-body problem, because the vast majority of bodies in the solar system have a completely negligible effect compared to the solar wind.
There is still uncertainty in the orbit of Apophis. That's why you still hear the odds of it passing through the 'keyhole' that will send it on a collision course with earth, rather than an explicit "yes" or "no". Yet with precise enough measurements, we could say that, and eventually will be able to.
So, yeah, the butterfly effect is just a joke in this context.
Re:Saving Earth is good... (Score:4, Informative)
Re:Then a butterfly flaps its wings (Score:5, Informative)
Yes it is. Orbits, unlike the weather, are not chaotic.
An orbit is not chaotic. Solving two orbits (three bodies) is the exact problem that lead to the development of chaos theory. [wikipedia.org]
Re:Then a butterfly flaps its wings (Score:2, Informative)
Remember when the Republican party used to be sane? Today's Republicans are the gift that keeps on giving to the Onion writers.