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- The last really big asteroid impact occurred in the Yucatan Peninsula about 65 million years ago. This asteroid was estimated to be 6 miles in diameter.
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- In 1908 a much smaller 56-foot-wide asteroid created an air-blast over Russia’s Tunguska River in Siberia. The blast leveled 60 million trees over an 1,330 square mile area.
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- Smaller asteroids enter Earth’s atmosphere all the time. Over one hundred 300-foot-wide asteroids are expected to strike over the next million years. During that same period two 3,000-foot-wide asteroids will hit. A rock this size delivers an explosion equivalent to 20,000 megatons of TNT.
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- The smaller asteroids only 300-feet-wide deliver a 20 megaton explosion.
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- The Asteroid Belt is believed to contain more than 750,000 asteroids that are larger than 0.6 miles ( 3,000 feet) diameter. The Belt is between Mars and Jupiter. Near-Earth-Objects, (NEO‘s) asteroids, orbit the inner solar system and some times cross paths with Mars and Earth.
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- Ceres one of the largest asteroids in the Belt is 583 miles in diameter. Ceres is now classified as a Dwarf Planet, like Pluto.
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- Some 150 asteroids have their own orbiting “ moons”. The two moons orbiting Mars, Phobos and Deimos, are believed to be captured asteroids.
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- The mass of all the known asteroids is less that the mass of the Moon. ( The Moon is 5% the mass of the Earth.) Most asteroids orbit in the “ Belt” between Mars and Jupiter. More than 200 of these have been measured to be over 60 miles diameter.
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- Well, how many of those > 3,000-foot-wide asteroids in “ Near Earth Orbit” are out there?
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- As amazing as it may seem nearly 500 of the NEO asteroids have been discovered. Of course finding them is just the first step. Astronomers need to track them over time to discover their orbits and their potential for “ close encounters”.
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- How do we protect ourselves from one of these impacts actually heading our way?
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- The 6-mile wide asteroid created a 120 mile wide crater in the Yucatan. The global environmental impact wiped out the dinosaurs and 80% of the animal species on Earth.
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- If another potential impact is imminent are we prepared to do something?
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- Would we send a rocket loaded with a nuclear bomb designed to blast the trajectory out of harms way? Could we do something the dinosaurs could not do?
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- Pound for pound nuclear explosions contain a million times the energy density of chemical explosions. The idea is to explode the bomb “near” the asteroid. The blast would be close enough to vaporize the surface of the asteroid. The expanding hot gases rising from the surface would provide the thrust needed to propel the asteroid off course.
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- In preparation for just such an event scientists have used X-ray radiation on meteoritic samples to learn how to best vaporize the surfaces. The plan changes between a stony asteroid and a nickel-iron asteroid so a recognizance mission is needed to determine an asteroid’s composition.
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- The calculations are that the most effective detonation occurs from a distance of 2 asteroid diameters away. The plan would be to use several small explosions rather than one big one. This would reduce the chances of fragmenting the asteroid and give us a chance to make adjustments with each detonation.
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- If an asteroid is coming with Earth as its target rather than just praying , it would be better to pray that the rocket works. Meanwhile let’s pray that we don’t have to face this situation. Stay tuned, astronomers are always looking for incoming asteroids. If it happens to be a long-period comet coming at us from the direction of the Sun we have little chance of ever seeing it before impact.
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