A comet collision with Earth, with catastrophic results, is inevitable. We have the technology to avoid it, but do we have the global cooperation and will?
Since its formation over 4.5 billion years ago, comets and asteroids have hit Earth many times. These objects, collectively known as Near Earth Objects (NEOs), still pose a danger to Earth today. Depending on the size of the object, such a collision with Earth can cause catastrophic damage on a local to global scale. There is strong scientific evidence that cosmic collisions played a major role in mass extinctions on Earth, as documented in fossil records.
It is also clear that such collisions can still occur today and into the future. One example is the 1994 Comet Shoemaker-Levy 9 , which broke apart and 21 fragments (some as large as 2 km in diameter) and crashed into the atmosphere of Jupiter. The damage to earth, had the fragments his it instead, would have been a catastrophe worthy of science fiction summer blockbusters (Who doesn’t remember fondly the two comet disaster movies from 1998, Deep impact and Armageddon).
Although most of the comets in our solar system pose no threat to our planet, every thousand year or so an object crosses earths orbit and raises the danger of a collision. Following a mandate by U.S. Congress in 1991, NASA started research into the detection and destruction of asteroids, followed in 1994 by the House Committee on Science and Technology directing NASA to cooperate with DOD and space agencies of other countries, to identify and catalogue the orbital characteristics of 90% of all comets and asteroids larger than 1 km with orbits that cross that of the Earth.
Following the 2003 NASA report from the Near-Earth Object Science Definition Team, Congress went even further and in 2005 assigned NASA the task of detecting 90% of near-Earth objects with a size greater than 140 meters in diameter, by the year 2020. These research programs already identified hundreds of thousands of NEOs and made great strides towards meeting the Congressional mandate to catalogue most of the 1 km and larger NEO’s (the ones most likely to produce a global catastrophe such as mass extinction), as well as the most dangerous objects down to 300 meters (objects that can cause major regional catastrophe), should they hit Earth.
What can be done about it: Scientists and engineers at B612 foundation are exploring ways to use a spacecraft to change the orbit of asteroids and other NEOs, with one promising approach being the “gravity tractor,” invented by NASA astronauts Ed Lu and Stan Love. This will involve a “spacecraft that can controllably alter the trajectory of an Earth threatening asteroid using gravity as a towline.”(pan-starrs.ifa.hawaii.edu).
Another option being explored is shooting at these asteroids to changes their trajectory. Japan revealed it successfully test-fired a space cannon designed to fire projectiles into NEOs. Ed Lu, a member of Association of Space Explorers that is pushing for global cooperation on this threat, said:
“There are 100 times more asteroids out there than we have found. There are about 1 million asteroids large enough to destroy New York City or larger, Our challenge is to find these asteroids before they find us.” And speaking of the February 15, 2013 Meteor that exploded over Chelyabinsky, Russia injuring 1,000 people, “Chelyabinsky was bad luck. If we get hit again 20 years from now, that is not bad luck–that’s stupidity.”
The bad news is that we live in a dangerous neighborhood with comets, asteroids and space debris traveling around in orbits that might get some of them into a collision “visit” with us, with catastrophic consequences. The good news is that we have the resources, technology, know how and brain power to protect our small green/blue planet and ensure these objects don’t reach us (science fiction after all is based on science). It is one world and it requires global cooperation and resources, which are underway and will only make us stronger and better as the one human race that we are.
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