When was the last near miss of a large asteroid in relation to the Earth?
The year is 1908, the location, Tunguska, Siberia. It's a rare warm summer afternoon in late June. You're a reindeer herder snoozing against a tree, while your flock grazes just outside the perimeter of the forest. When, all of a sudden, you are awakened by an unusual noise overhead. You look up, and you see a bright, fiery streak of light racing from the horizon, over your head and exploding just out of sight over the canopy of trees your sitting along side. It's an explosion unleashing more than 500 times the energy of the future nuclear detonations of Nagasaki and Hiroshima. The blast flattens the forest in an 18 mile radius from ground zero, three miles above the forest floor. Most trees in the blast zone are literally incinerated. 60 miles away, people are thrown for yards across the ground as the windows to their homes are blown out. The Northern sky appears as if it's on fire. Large seismic vibrations are felt as far as 600 miles away, and weather forecasters 2,200 miles away in England note unusual air disturbances (PERMANENTweb).
Sound like a great opening to the next killer asteroid flick? Think again. This is an actual account of a real asteroid strike in the early twentieth century. Had the circumstances and location been just a bit different, movies about killer asteroids may have been around long before the late 1990's.
Killer asteroids, or what are commonly referred to in the science world as near earth objects, or NEOs, are more than just science-fiction. They are a very real, but rare threat that has occurred in the past and, unless we prepare, it will happen again. The only question is when.
Where They Come From and How They Get Here
The movies and network newscasts don't take much time to explain where these gigantic rocks come from. One would get the idea that these over-sized boulders just happen to be floating randomly about the universe, when in fact, most of them aren't very far from home...relatively speaking.
Approximately 60 percent of near Earth asteroids originate in our solar system's very own asteroid belt, which is located between the orbits of Mars and Jupiter (PERMANENTweb). This belt of pre-planetary debris may contain well over one million asteroids, however, only about 20 thousand are large enough to have been tracked and have known orbits (PHYSICSweb; Binzel 2004). But this brings up the question of how these rocks find their way out of the asteroid belt and in to Earth's path.
Within the asteroid belt lie 3 empty orbital regions known as the Kirkwood gaps. These zones act as a sort of "celestial slingshot" that ...
In just over 1,700 words, this solution discusses the many different odds and probabilities of a Near Earth Object (NEO) striking Earth within some of our lifetimes. It also discusses how long it is thought that it would take to identify more than 90% of these threats, and the two major ways in which we should deal with them once they are identified: deflection and destruction. This essay starts out with a 1908 account of a large object entering the Earth's atmosphere over Siberia, and the damage it caused, and continues with a discussion of where these objects most likely originate as well as what the author feels is the best course to minimize our race's risk when it comes to these potential global killers.