The Death of the Dinosaurs
The eruption of Mt. St. Helen's volcano and the fall of dust it spread reminds of another incident, similar in nature, but much larger, thought to have occurred sixty-five million years ago. Then, the dinosaurs and flying reptiles inhabited the earth--the large mammals and man had not yet come into existence.
Then one day, according to findings of Luis Alvarez and colleagues at the Lawrence Berkeley Laboratory, the tranquility ended and, alas, so did the dinosaurs and the magnificent 25-foot wingspan pterodactyls. In fact, it is estimated that half of the plant and animal life on our planet perished. The end for them probably came rather quickly.
According to Alvarez's findings, an earth-crossing meteoroid, about 6 miles in diameter and weighing about one million-million tons, collided with the planet. At some unknown site, perhaps a location now eroded away by ongoing tectonic activity, the meteoroid generated a crater 250 miles in diameter and hurled pulverized rock from the meteoroid itself high into the atmosphere.
The explosion had a force approximately one-hundred-million times greater than the eruption of Mt. St. Helen's! The conclusion that this event happened comes from the finding of a one-inch layer of 65-millionyear-old ash containing iridium, osmium and other elements commonly occurring in extraterrestrial objects, but not common on earth. The layer was found at such widely-separated places as Denmark and New Zealand.
Calculations made at the Geophysical Institute indicate that the huge ash cloud cast into the atmosphere by the collision turned day into night. The night lasted for 3 to 6 years. The lack of sunlight reaching the surface caused the plants to die and eventually, the dinosaurs. Also during these dark times, the earth's temperatures fluctuated upwards and downwards perhaps 10oC from the current average 12oC (54oF)
