Bonus Blog: Astronomy and Saving the World from Astroids!

http://www.daniel-irimia.com/2012/12/04/video-simulation-apocalypse-caused-by-asteroids-impact-equals-detonation-of-100-million-tons-of-tnt/

On February 15, 2013, a seventeen meter long astroid came roaring through the air above Chelyabinsk, Russia. Although the astroid mostly dissipated in the air, the event broke windows is reported to have injured more than a thousand people. Despite the damage caused by this relatively small meteor, experts are aware of the consequences that could have occurred. We were particularly lucky that the angle of impact was large enough that the astroid didn't significantly impact the earth.

As a result of this event, however, more awareness has been turned to developing mechanisms to protect our planet from future astroid collisions, and quite importantly to protect our species from the fate of the dinosaurs. In this blog post, we'll examine some of the protocols and techniques being explored to potentially save our planet!

The Chelyabinsk astroid posed an interesting issue to astronomers, since it came in a unique size that was large enough to be dangerous, but small enough that it was undetected until breaching our atmosphere. Scientists set the probability of these types of astroids approaching earth between ten and a hundred years.

A congressional project dubbed Spacedguard mandated that NASA aim to find 90% of all near-Earth astroids greater than 1 kilometer by 2005. This project was severely underfunded, and produced meager results.

ATLAS (Astroid Terrestrial-impact Last Alert System Project)

http://www.huffingtonpost.com/2013/02/21/asteroid-early-warning-system-atlas-space-rocks_n_2728101.html

Beginning this year, a new project is being implemented called ATLAS. This is designed to provide at least a week's notice for astroids around 45 meters, and three week's notice for those around 140 meters. To improve on these types of space surveillance, government agencies are looking more and more towards launching satellite telescopes to that can constantly monitor for meteors. This overcomes the significant limitation of earth telescopes that can only work effectively at night.

Some initial techniques proposed to protect against smaller astroids in the future include laser beams and nuclear missiles, which at this point are still under developed for useful applications in this area. Some more novel approaches, however, are also being examined for development quite a ways into the future. One method is known as a gravity tractor. This relies on early detection of a potential astroid collision. If detected early enough, a small spacecraft could be sent to the astroid, and gradually alter its path. Over several months, this method could push the astroid off it's colliding path with earth, and save the day!

Mirror Bees

http://www.nytimes.com/2007/12/09/magazine/09_5_asteroid.html?_r=0

An even more far off approach known as 'Mirror Bees' would utilize many small spacecrafts, each with focusing mirrors to direct the sun's light at one point on an astroid. This would be used to heat the small area to the point of vaporization, thereby creating a propulsive jet. Again, applying this over a period of time, this would be used to nudge the astroid off course, thus redirecting it away from its trajectory towards earth.

While the track record of neglecting funding, and far into the future approaches being proposed don't exactly instill confidence, it is important and exciting first step that approaches are even being thought of and considered. Particularly with the rapid growth and expansion of technology, it will be exciting to see the next stages of this developing field!

Resources: 
http://www.space.com/13524-deflecting-killer-asteroids-earth-impact-methods.html
http://www.wired.com/2013/02/asteroid-watching-mitigation/