Anyway, the first 'shot over the bow' occurred with the explosion of an 11 ton (~2.2. x 10 4 kg) meteoroid over the Russian Urals barely 12 hours ago by Russian local time. The blast broke windows in 6 cities according to an MSNBC report this morning, and injured 1,000 people, while 3,000 buildings sustained damage mostly from the blast shock wave. See, e.g.
The incident recalled for many the Tunguska Siberian event in 1908 which knocked down nearly 80 million trees and decimated nearly 820 square miles, about two-thirds the size of Rhode Island. And this was from an object perhaps ten times the size of the 11 ton meteoroid that just hit the Urals this morning.
Meanwhile, a much larger asteroid, the one identified as DA 14 2012 is making its closest pass barely three hours from now. It packs a mass of 130,000 metric tons (~ 2.9 x 108 kg) and with the explosive release equivalent of a 20 megaton nuclear bomb. Incredibly, the object was first discovered back in February last year by a DENTIST using a high powered telescope! Why the hell had no national scientific agencies made the discovery? What would have been the case if, instead of a minor midget asteroid making this close pass, it was a planet killer 6 km across or larger? (As opposed to only 150' or 45 m DA 14 2012) Would we be ready to do anything other than piss, moan and pray?
It seems doubtful! This despite evidence that we truly are living in a fool's paradise of false security! As far back as 1979, in an interview given to the BBC, Dr. Basil Boothe warned it was most unwise of humans to bet on their future security from approaching cosmic objects. This would be by assuming that their lone home planet would remain untouched, unaffected and they could sleep in peace. Not so! He estimated at least a 50-50 chance of a strike by a planet killer within 250,000 years. Sadly, this long timeline - misunderstood by the budget cutters- has been taken to mean we can do nada for a quarter million years, as opposed to a strike happening at ANY time between NOW and a quarter million years hence.
Indeed, as recently as 1994 Earthlings also observed transfixed as nearly 21 immense fragments from Comet Shoemaker Levy 9 crashed into Jupiter. Had they instead smashed into our own planet, we might not even be having this discussion.
Meanwhile, Projects Space watch and Spaceguard remain on relative life support, funding wise. The first, based at the University of Arizona, featured generous grant allocations in its early years when it discovered over 1,300 Earth -approaching asteroids by 2002. As the austerity mindedness infected all science research areas, that capability has since wound down a lot, leaving Spacewatch mostly in the hands of amateurs. Not that the latter aren't observationally capable, but we also need professionals to spot these things and then (using the well known equations of celestial mechanics) to obtain the orbital parameters as fast as possible.
Spaceguard extends the detection to focus more on NEOs (near Earth objects) as opposed to singling out near Earth asteroids (NEAs). Again budget limitations have loomed and imposed truncated observation time frames and selectivity.
Although there have been many discoveries of near-Earth the Spaceguard Project has been criticized for not having an in-depth master plan if our humble planet is directly in the crosshairs of a giant asteroid. It has also been criticized of having false alarms that could lead to dangerous implications.
NASA published an article in April of 2001 to clarify many questions that have come up with this project. The report distinguished the difference between NEOs and NEAs, why the organization selected NEAs with a diameter of at least one kilometer in diameter, why the number of 90 percent was chosen and many other questions that have perplexed the general public.
Neither Space watch or Spaceguard is adequately funded, which means that either an NEO or NEA can escape through the observational 'net' and could wreak havoc, especially if the size and mass approaches that of a planet killer such as exterminated the dinosaurs.
In addition, there is no plan of which anyone is aware for taking out a planet killer - say 6-10 km across, if one does target Earth. There have been past ruminations about using nuclear weapons to try to split the object into smaller pieces, but that was put aside when the ''architects" decided a number of smaller (1 km ) strikes might not be so good either. But still, a planet killer of 6 km arriving intact is not something to dismiss lightly and our space gurus may well have to opt on the side of losing half of the earthly populace to losing ALL of it, say from a nuclear winter onset as a result of some 10 28 kg of dust and debris in our atmosphere, cutting off sunlight.
We have the brains, supposedly, and given we aren't planning to abandon 'Mother' Earth any time soon, we had better damned well come up with a credible plan to deal with a monster planet killing asteroid if and when one appears and approaches us - whether that be next year, or in ten thousand. It is either that, or we go the way of the dinosaurs, in which case, our vaunted intellect wouldn't have made a dime's worth of difference!