One of the longest-running discussions in modern science revolves around what caused the dinosaurs to become extinct more than 65 million years ago. In fact,today most scientists agree that more than 70% of all life on Earth perished at this time.
The debate about what caused this mass extinction has long centered around two major theories. The first claims that the effects of increased volcanic activity on the environment rendered it inhospitable to life,while the second looks to the heavens and blames the sudden impact of a large object from space hitting the earth’s surface.
In the late 1970s,the Mexican state-owned oil producer Petroleos Mexicanos (PEMEX) found an enormous underwater arc facing southward in the Caribbean Sea near the Yucatan Peninsula. A geophysicist for PEMEX compared the arc with earlier surveys of the area and discovered an identical arc facing northward that had been discovered during the 1960s. When he matched up the two surveys,it became apparent that the ends of the arcs matched up perfectly to form a circle under the sea that is 180 kilometers wide.
The crater’s center is located at the tiny coastal village of Puerto Chicxulub,which lies about an hour north of Merida. Today,experts believe that the underground circle is actually a crater that was formed millions of years ago. By the 1990s geologists had matched mineral and rock samples that were found throughout North America and the entire Caribbean to the crater,a discovery that seems to link it to the Alvarez Theory of how the dinosaurs were driven to extinction.
According to scientists,the meteor would have been more than 10 kilometers in diameter and upon impact would have unleashed a force equal to 100 million megatons (which equates to 100,000,000,000,000 tons) of TNT. To put this in perspective,this would be the equivalent of 5 million Hiroshima-sized atomic bombs.
Not surprisingly,the crater is believed to have affected the entire groundwater system on the Yucatan Peninsula,which in many areas has eroded the limestone to produce caves and freshwater sinkholes known as cenotes (pronounced sayno-tays). Today,cenotes are a common part of the Yucatan’s geographical features,with hundreds having been discovered throughout the region. The ancient Maya used them for religious ceremonies and as a source for drinking water,and they are still used to provide fresh water for cities in the area to this day. From an aerial view,the cenotes clearly mark the rim of the Chicxulub Crater,and are the only visible surface indicator of its existence.