Thursday, September 7, 1995

Most people have heard by now that the great dinosaur mystery is probably solved. The great beings that ruled the Earth a hundred times longer than man, and that continue to haunt our dreams and imaginations, were almost certainly killed by the impact of an asteroid. The evidence is still mounting, with more discoveries made every day. They've even found the crater - an immense ring of fractured rock buried beneath Yucatan, and called by the wonderful Mayan name of Chicxulub (CHEEK-shoe-lube). But don't let the charming name mislead you. It means "Tail of the Devil," and that circle on the seismic charts is a memorial to one of the worst days in history.

The asteroid is estimated to have been six or seven miles across, about the size of the city of San Francisco. It came streaking in at forty thousand miles per hour, tearing a massive tunnel through the atmosphere. The blast was the equivalent of a Hiroshima-sized bomb for every person now on Earth, all going off at the same time and place. It blasted a hole in the Earth a hundred miles across and six miles deep. The heat of the blast vaporized the ocean, the sea floor, and the asteroid itself. A stream of incandescent gas spurted out into space through the hole in the air, and a half hour later came raining down all over the Earth as white hot rain, setting fire to every forest and plain on Earth. Vast hurricanes of flame swept across the land, incinerating all before them. A wave three miles high roared away from the impact site at hundreds of miles an hour, flooding the continents and burying the coasts in thick layers of sea floor gravel and dying sea creatures. Massive earthquakes and volcanic eruptions rocked the planet. But this was only the initial impact. The worst was yet to come.

The dust from the explosion blotted out the sun, altering weather patterns and stopping photosynthesis, killing most land and sea plants and the animals that fed on them. The temperature plunged, bringing permanent winter weather. Bitter acid rain polluted every lake, river, and stream. The ozone layer was stripped away, exposing the few survivors to lethal cosmic radiation. Every ecosystem collapsed as key species died out of every food chain.

The magnitude of such a global disaster is beyond conception. But an large continent-destroying impact occurs about every hundred thousand years. There have been many great extinctions, some even worse than Chicxulub. The one at the end of the Permian killed up to 97% of all life on Earth. How could anything survive catastrophe on such a scale? And yet after each crushing blow, a tiny remnant of the original fauna has survived, then evolved to fill the vacant ecological niches again.

What types of creatures would these survivors be? No evolutionary training can prepare an organism for such rare events as supernovae or asteroid strikes. Size, strength, ferocity, even intelligence, would matter little against global environmental destruction. Make no mistake - for all our knowledge and technology, there is little we could do to help us survive such an impact. We would have no more chance of surviving than the dinosaurs did.

No, the only way a species could survive is if a significant portion of that population is in shelter at the time of the disaster. Creatures that live in holes and deep places, or entirely underground, would have the best chance.

What kinds of creatures habitually live in shelter? Those that need it to survive; those who do not have size or strength or ferocity or intelligence; and who must therefore hide from those who do. Small unaggressive creatures that lay low and quiet when the big guys are stomping around. It is they that will live to repopulate the empty planet. It is, in fact, the meek that shall inherit the Earth.

copyright 1996 by Brian K. Crawford