On A Collision Course With Earth

Created: Friday, 18 August, 2006

I edited this article from Reader's Digest February 1997. This article is good for me to fear God and treasure LIFE everyday.

    You look up in the sky and see something strangely bright. An hour later it appears even more brilliant. The object grows larger and brighter until, three hours later, it enters Earth's atmosphere. Is is an asteroid, and it ignites into a blinding fireball that strikes the surface of our planet seconds later.

    Ground zero is a shallow sea; the impact generates enormous tsunamis that flood coastal regions a thousand or more miles away. Dust and gas fly heavenward and as they rain back down to Earth, the energy released heats the atmosphere to the temperate of a kitchen oven on broil. Land animals roast. Forest burst into flames. Dust particles and smoke block out the sun. In the darkness, plants perish and animals starve. Earth plunges into a deep freeze.

    Sulfuric gases released from vaporized rock mix with water in the atmosphere to form acid rain, which falls to Earth, killing tiny marine plants. The food web of the ocean collapses.

    Sound farfetched? This list of horrors, many scientists believe, describes what happened when a meteorite more than six miles wide struck Mexico's Yucatan Penisula 65 million years ago. Some scientists believe the collision triggered a mass extinction that wiped out two-third of Earth's species, including the dinosours.

    Asteroids are rocky or metalic objects ranging in size from particles to tiny planets nearly 600 miles across. Most orbit the sun in the main asteroid belt between Mars and Jupiter - kept there by Jupiter's termendous gravitational pull.

    Occasionally two main-belt asteriods collide, ejecting fragments that veer into the inner solar systems, possibly intersecting our planet's orbit. The gravitational tug of Jupiter can also nudge an asteroid's course so that is orbits in a near-Earth path. So far, astronomers have discovered more than 300 objects that could cross Earth's orbit, though none is predicted to hit any time soon.

    Objects measuring between 300 and 3000 feet are estimated to strike only every 1000 to 200,000 years. If an object some 1600 feet hit land, the impact would create a three-mile-wide crater and destroy almost 4000 square miles of property. A hit in New York City's Central Park could kill 25 million people.

    Just last May 19, an asteroid about one-quarter of a mile in diameter whizzed past only 280,000 miles away - approximately the distance to the moon. This was the largest object over spotted so close to Earth. Most unsettling, astronomers didn't see the asteroid until just a few days before it zipped by.