Saturday, October 27, 2012

Looking At It From a Different Perspective

The flick, Armageddon, where intrepid astronauts blow up a menacing astroid using nukes, has been debunked by scientists stating said tech employed could never do the job.

The heroic act, made possible by Willis's drilling expertise, splits the asteroid into two even halves which drift apart and fly relatively harmlessly past either side of the planet, saving humanity from extinction.

But now the effectiveness of the solution has been called into question by a group of physics students who claim mankind does not possess a bomb big enough to do the job.

A mathematical analysis of the situation found that for Willis's approach to be effective, he would need to be in possession of an H-bomb a billion times stronger than the Soviet Union's "Big Ivan", the biggest ever detonated on Earth.

Using estimates of the asteroid's size, density, speed and distance from Earth based on information in the film, the postgraduate students from Leicester University found that to split the asteroid in two with both pieces clearing Earth would require 800 trillion terajoules of energy.

In contrast the total energy output of "Big Ivan", which was tested by the Soviet Union in 1961, was only 418,000 terajoules.

Deep Impact, from the scientific perspective, fares better but blowing up the comet is not only impossible but also is a bad thing to do.

 Both movies missed the opportunity to startle the audience with enormous sonic booms. The fragments that strike Earth are travelling about 100 times faster than the speed of sound. Deep Impact did do a wonderful job of showing the atmospheric pressure wave, which expanded outward from the collision site.

     In Deep Impact, the comet is blown up by several nuclear devices at the very last moment. It is understandable that Hollywood wants to create as dramatic a movie as possible. But such a procedure would not save the world. It is impossible to pulverize a comet as portrayed in the movie. The nuclear devices would break it up into fragments that would act like a multiple warhead. The devastation might even be worse, as the destruction would be spread over a larger area of Earth. The atmosphere would suffer more damage.

But, there could be a way to avert disaster, if we have enough warning, by simply painting the object in question with white paint, a suggestion posted by an MIT grad student who looks at this problem from the creative perspective. :) (Note - Comets are dark, dusty bodies of ice.)

Given sufficient warning, an asteroid headed on a collision course with Earth could be diverted by firing paintballs at it, an MIT graduate student has calculated. While the idea might seem facetious or amusing on its face, it was good enough for Sung Wook Paek of MIT's department of aeronautics and astronautics to win the 2012 Move an Asteroid Technical Paper Competition sponsored by the United Nations' Space Generation Advisory Council, which solicits creative solutions from young professionals. Paek presented his paper this month at the International Astronautical Congress in Naples, Italy.

Paek's proposal would work on two different levels. The paintballs themselves would impart a slight momentum change to the incoming asteroid, diverting it slightly -- but probably not enough to avoid a collision. But using white paint or other light color in the paintballs would increase the asteroid's albedo, or reflectivity. The pressure of photons of sunlight bouncing off the asteroid could, over time, provide a much greater shift in course. A similar effect is behind using solar sails for spacecraft: Light striking the sails and being reflected would provide impetus to move the craft.

Alternative approaches to the solving of complex problems is good for the soul. - Robert E.

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