You said:

Moreover, *if* evidence for AGW was really there then the IPCC and CRU wouldn’t have had to fake or exxagerate it or manipulate the data to “hide the decline” as Climategate has proven they did.

Any credibility you had got its coat and left at this point.

I imagine a relatively small, unmanned Orion craft could be built and launched in less than a year if we threw enough money at it.

Of course, one might also take the position that, because we would be unlikely to be able to develop, construct, and launch an orion space-ship in less than the lead time from detecting an Earth Crossing Threat, all the more reason that we should begin the work immediately.

That’s why you would use a single Orion spacecraft, rather than several single-device missiles.

If we had one built and ready. To develop an orion type spacecraft would take years and more years to build it. Not something you could do in two years.

That’s why you would use a single Orion spacecraft, rather than several single-device missiles.

That, and it would be much cheaper (price per kg of payload on a large Orion craft is something like a few cents, compared to hundreds and thousands of dollars per kg on much smaller chemical rockets) and an Orion craft would have high enough delta-V to redirect multiple inbound objects with little lead time, or redirect a single object and then perform some other mission, such as exploring the outer system, or traveling to another star.

The 8MT ‘super’ Orion could redirect multiple asteroids, travel to Alpha Centauri, and then turn around and come back (following the Momentum Limited 1G acceleration profile, it could do all that within a single human lifespan, less than 90 sidereal years)

Good stuff though. Thanks for the heads-up, Phil.

Sounds cool! Have you read Jerry Pournelles, Lucifers Hammer? It addresses some of those post impact concerns.

Gary 7

After that the story focuses on how humanity deals with the remaining days before the 28 kilometer monster arrives and impacts in southern Chad.

So comets are very much on my mind lately.

… Provided large bangs are involved the USA government seems capable of moving very rapidly. I would assume that in their childhood most of the military were forbidden to have fireworks. …

New solution to give us World Peace (the goal of beauty queens everywhere! ) :

Legalise and promote the use of fireworks for all children everywhere!

Can I have my Nobel peace prize now or should I wait until it actually works in practice?

@ 35. Shadowslayer81 Says:

Call me an optimus

Prime?

@ 44. Chris Says:

@Barry It depends. If the asteroid has the consistency of a pile of gravel, you could just end up ejecting mass from the opposite side of asteroid. Kinda like a Newton’s cradle.

Ah but *what* a Newton’s cradle! It wouldn’t fit on my desk that’s for sure.

There are a number of ideas to deal with every contingency – almost – and the BA has discussed several asteroid impact avoidance schemes before & in his book.

A loose gravel pile is probably the hardest sort to shift but *if* we have enough warning I’m sure we could arrange something I’m sure. Maybe a mass-driver “landing” on it and then ejecting a steady stream of its own rocks in the right direction to move it off-course would work best there?

Or could we heat-fuse it together with high temperatures somehow then shift it as a whole? Or achieve the same with water ice or wrapping it up somehow?

Or, final thought, could we use *another* asteroid against it and direct a non-threatening rock to collide with and shatter or knock off course a threatening one?

As far as the explosion in diversity is concerned, I would surmise the total amount of biomass on the planet remains pretty constant. It’s difficult for small critters to succeed in an environment populated by giants. Remove the giants and the small critters can go for the gusto and fill a myriad of ecological niches previously occupied by a single giant.

Brontosaurus weighed in at around 60 tons. That’s a lot of biomass that could represent several dozen smaller species if the giant is removed.

GAry 7

… after The Big One (the Permian extinction) for some unknown reason diversity observably soars for every extinction event.

Probably for the same reason that traffic soars whenever the local government provides more parking spaces!

Seriously, there isn’t a serious problem with impacts. Life is the better from it. The Last Heavy Bombardment provided the volatiles that kick started life, likely even as the impactors happened.

While the ‘dinosaur killer’ didn’t even kill the dinosaurs – as our current dinosaurs, the birds, attest to. (There’s twice as many bird species than the old and tired mammal branch.)

In fact, while early extinctions drove diversity down every time, after The Big One (the Permian extinction) for some unknown reason diversity observably soars for every extinction event.

And the latest data AFAIU is that this higher diversity is attained after merely ~ 1 My. Extinctions is commonly Earth’s “pick-me-up”.

Not that I won’t support hazard mitigation of any form, due to morality of preventing human suffering if nothing else. This is only the second time we realistically can do anything about a major threat to humanity. (The ozone barrier extinction prevention being the first. And the AGW fast becoming a lost cause – observably higher temperatures aren’t as “sexy” threatening as impactor close calls, just ask the frog fast cooking in the pot.)

Let’s do it!

I suggest you both look into Project Orion, and specifically, Nuclear Pulse Propulsion.

An Earth Shattering Kaboom, while satisfying, would not be nearly as effective as using a string of much smaller kabooms to simply push the offending object out of the way.

http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29

http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion

@ 44. Chris:
just make sure the debris isn’t ejected towards you, unless the momentum transfer is perfectly elastic (it isn’t) you’ll still impart some velocity to the rest of the pile.

http://en.wikipedia.org/wiki/Newtons_cradle

http://www.huffingtonpost.com/robert-lanza/anything-beyond-the-unive_b_455260.html?page=3&show_comment_id=39890473#comment_39890473

All critical comments will be censored.

http://www.huffingtonpost.com/dana-ullman/the-case-for-homeopathic_b_451187.html

Provided large bangs are involved the USA government seems capable of moving very rapidly.

As the old joke goes:

The US Air Force: when it absolutely, positively has to be destroyed overnight.

Just because we’ve been lucky, doesn’t mean that luck will continue to hold.

Then there is this:

http://news.nationalgeographic.com/news/2010/02/100203-asteroid-collision-earth-global-cooling/

,,,which suggest asteroid impacts MAY occur more often than we thought.

My take on moving an asteroid is to use solar powered mass drivers, using the asteroids mass as reaction material to alter its orbit. Of course, we have the problem of asteroid rotation to deal with. One possible solution is to bombard the asteroid with charged particles, maintaining an opposite charge on our interceptor. The electric field effect is on the order of 10^40 times as powerful as the gravitational interaction between asteroid and space craft. A plasma drive for the craft, with an ion projector to charge the asteroid(if we charged both the craft and the asteroid with the same charge) would allow the ship to “push” against the asteroid.

There are probably as many viable solutions as we have commenters here. Selecting the best and implementing them is as much a political problem as a technical one.

Gary 7

Wrong! No amount of nuclear exposives would stop an impending comet impact! If we used enough explosives to shatter the comet, most of the resultant fragments would still be in the same orbit, and still on course to hit the Earth.

FAIL. They would be NOT on the same orbit. Mere dV of 0.1 m/s is enough to make a comet fragment miss if the explosion happens a year before impact. And most of the fragments would be kicked aside by far more than that. Sure, some would hit. But given the choice of being hit by one 60 km comet, and say 100 1km fragments, I am sure, any non-suicidal civilization would choose the latter alternative. Because it is survivable, while the former is not.

Your 1972 fireball reference was to The Great Daylight Fireball of 1972: http://apod.nasa.gov/apod/ap090302.html

I remember seeing a sequence of stills from the 8mm movie on the cover of Sky & Telescope that year. APOD says it was truck-sized and may have left fragments from an air-burst if the trajectory was less tangential. Quite a number of people witnessed this daylight event in the western US. Pity for all those collectors out there…..this one got away.