LOS ANGELES, CA (Catholic Online) - The most common date given for the extinction of the dinosaurs is the round estimate of 65 million years ago. Research now shows the extinction event occurred a bit earlier than that, about 66,038,000 years ago, give or take 11,000 years.

The event was initiated by the impact of a massive asteroid, about six miles in diameter. That asteroid struck immediately off the coast of the Yucatan peninsula, leaving a crater 110 miles wide in a blast that was larger than the atomic blast which destroyed Hiroshima, by a factor of about a billion.

None of these figures are guesses or exaggerations. The science for determining the size and composition of impact objects, as well as dating methods, is well-tested, verified, and quite exact.

However, scientists also know that the dinosaurs were also greatly distressed, on the whole, thanks to a favorite culprit of the modern age - climate change.

Today, climate change is a hotly debated topic, however the historical record reveals that climate change is very much a part of the natural cycle of things on Earth. There have been times when the atmosphere was much more rich in oxygen, and others carbon dioxide. The swings in these gasses also reveal swings in temperature as the Earth repeatedly went from ice age to warm period like a pendulum on a clock.

These swings in climate have not only been difficult for humans, who have had to contend with minor temperature upswings in the past several decades, as they were for the dinosaurs, who had to endure dramatic cooling events.

Although debate continues on the matter, most of the dinosaurs, though possibly not all, were cold-blooded animals. This means they required a warm environment to flourish. Scientists now believe that rapid swings in climate in the preceding million years before the Chicxulub event, brought the dinosaurs to the brink of extinction. The impact simply finished the job.

Chicxulub was fatal to the dinosaurs because it threw massive amounts of dust into the upper atmosphere, where it reflected soar energy back into space. This made the planet go into a darkness that may have lasted weeks, and an ice age that could have lasted for years.

In that climate, the dinosaurs simply could not survive.

Of course, this paved the way for the emergence of and diversification of mammals, which eventually became dominant.

Scientists are reporting their findings in the current issue of the journal Science. They will need to train themselves to quit saying, "about 65 million years ago", and change it to 66.

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