What killed the dinosaurs? [
http://www.wf.carle…] Their sudden disappearance 65 million years ago, along with about 70 percent of all species then living on Earth, is known as the K-T event [
http://bang.lanl.go…] (Cretaceous-Tertiary Mass Extinction event). Geologists and paleontologists often entertain the idea of a large asteroid or comet impacting [
http://rainbow.ldeo…] the Earth as the culprit. Besides the firestorms, tidal waves, earthquakes, and hurricane winds such an impact [
http://web.mit.edu/…techreview/www/artic les/feb95/tyson.html ] would generate, the debris thrown into the atmosphere would have a serious global environmental impact -- creating extended periods of darkness, low temperatures, and acid rains. In 1990, dramatic support for this theory [
http://juliet.stfx.…academic/geology/cou rses/170/whatsnew/bi osph/dino2.html ] came from cosmochemist Alan Hildebrand's revelation of a 65 million year old, 112 mile wide ring structure still detectable under layers of sediment in the Yucatan Peninsula region of Mexico. The outlines of the structure, called the Chicxulub crater [
http://bang.lanl.go…] (named for a local village), are visible in the above representation of gravity and magnetic field data from the region [
http://www.agu.org/…]. In addition to having the right age, the crater is consistent with the impact [
http://antwrp.gsfc.…] of an asteroid of sufficient size (6 to 12 miles wide) to cause the global disruptions. Regardless of the true cause of the K-T event, it is fortunate that such impacts are presently believed to happen only about once every 100 million years! [
http://ccf.arc.nasa…]
Explanation
What killed the dinosaurs? [
http://www.wf.carle…] Their sudden disappearance 65 million years ago, along with about 70 percent of all species then living on Earth, is known as the K-T event [
http://bang.lanl.go…] (Cretaceous-Tertiary Mass Extinction event). Geologists and paleontologists often entertain the idea of a large asteroid or comet impacting [
http://rainbow.ldeo…] the Earth as the culprit. Besides the firestorms, tidal waves, earthquakes, and hurricane winds such an impact [
http://web.mit.edu/…techreview/www/artic les/feb95/tyson.html ] would generate, the debris thrown into the atmosphere would have a serious global environmental impact -- creating extended periods of darkness, low temperatures, and acid rains. In 1990, dramatic support for this theory [
http://juliet.stfx.…academic/geology/cou rses/170/whatsnew/bi osph/dino2.html ] came from cosmochemist Alan Hildebrand's revelation of a 65 million year old, 112 mile wide ring structure still detectable under layers of sediment in the Yucatan Peninsula region of Mexico. The outlines of the structure, called the Chicxulub crater [
http://bang.lanl.go…] (named for a local village), are visible in the above representation of gravity and magnetic field data from the region [
http://www.agu.org/…]. In addition to having the right age, the crater is consistent with the impact [
http://antwrp.gsfc.…] of an asteroid of sufficient size (6 to 12 miles wide) to cause the global disruptions. Regardless of the true cause of the K-T event, it is fortunate that such impacts are presently believed to happen only about once every 100 million years! [
http://ccf.arc.nasa…]
Explanation
