Sandia simulation shows small near-earth objects can cause big troubles

William Atkins
Saturday, 22 December 2007 21:02

Science - Space

A Sandia supercomputer has found that the space body causing the Tunguska explosion, which destroyed hundreds of thousands of acres and thousands of animals, in Siberia in 1908 was 3-4 times smaller than what first thought. Humans should pay attention to these smaller space bodies for the sake of millions of lives.           

The Tunguska explosion, sometimes also called the Tunguska Event, was a huge explosion that occurred in Siberia in 1908 near the Podkamennaya Tunguska River. The area is now called Krasnoyarsk Krai, Russia.

The blast flattened over one-half million acres (780 square miles or two thousand square kilometers) of pine trees and other planet life and killed thousands of reindeer and other animals. The isolated area contained few humans in 1908. The number of humans killed on that day is unknown.

Scientists have generated many theories on what caused the Tungaska Event. Most scientists contend that an asteroid, comet, or meteor flying through outer space collided with the Earth. The force of the two bodies hitting each other generated huge amounts of energy, causing the devastating explosion that occurred in Siberia in 1908.

Initially, scientists estimated the size of the space body was 150 to 300 feet (45 to 90 meters) in diameter, and than the impact of it with the Earth generated a power blast equivalent to 10 to 40 million tons of TNT.

However, now, scientists from Sandia National Laboratory, in Albuquerque, New Mexico, state that the space body, according to their supercomputer Red Storm, was only about 65 feet (20 meters) in diameter, not 150 to 300 feet as first thought, and generated a blast equivalent to about four million tons of TNT, not 10 to 40 million tons of TNT as initially thought.

Even at that smaller size, it destroyed an area the size of a major world city. If one hit Earth today, it would have the potential of killing millions of human lives.

The Tunguska body, only 65 feet (20 meters) across, generated more energy than four million tons of TNT. The Sandia scientists compared this energy to the atomic bomb that the United States dropped on Hiroshima, Japan during World War II (1939-45): this small space body hitting the Earth was one thousand times more powerful than that atomic bomb.

Research scientist Mark Boslough, from Sandia National Laboratory in Albuquerque, New Mexico, remarked after the results of the Red Storm computer program came out, “… we should be making more efforts at detecting the smaller ones [asteroids] than we have till now.” [Fox News “Small Asteroids Pose Bigger Threat Than Thought”]

Thus, the Sandia scientists conclude that a relatively small space body has the potential to cause a massive explosion on Earth if it should hit the Earth, especially if such an explosion occurs in a densely population section of the planet.

Boslough contents that the space body blew up about five miles (eight kilometers) from the surface of Earth while traveling at hypersonic (faster than sound, or supersonic) speeds. Most of the energy of the explosion headed straight to Earth in jets of expanding superheated gases traveling at supersonic speeds, what Boslough describes as “supersonic white-hot mega-tornado rings.” [Sky and Telescope “Tunguska’s Blast: Less is More”]

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