History and Environmental Factors: Astronomical Events


Figure 1.--The Hoba meteorite is the largest extraterrestial object ever found on earth. It is an iron meteorite which weighs about 60 metric tons. It was found by a farmer when his plough struck it. It is located near Grootfontein, Namibia. What is amazing is that there is no cratter for such a massive object. Very different from Meteor Crater Arizona. Astronomers believe that the meteor entered earth's atmosphere at a shallow angle. It was large enough not to burn up and was slowed down by atmosphere before impact. The photo here was taken during a vacation trip of an Afrikaner South African family to Namibia.

Astronomical events have the potential of causing huge environmrntal damage. This is because they are so powerful uncommon. Life evolves to normal environmental conditions. These events can abruptly change such conditions. A collpsing nova has the potential of emiting a burst of energy in the form of X-rays which even from the great distances involved could whipe out all life on earth. Such an event is, however, highly unlikely. Much more common are meteors and comets striking earth. Depending the size of the object, these events can have a massive climatic event. Most meteors are small shooting stars which are vaporized in the atmosphere. Large meteors have struck the planrent. Comets can also have disatrous impacts. There have beem much larger events. A much more common astronomical event is sun spots which can have significant climatic impacts. Astronomers have detected an 11-year cycle, although it is subject to significant variation over time. The best known is the Chicxulub event off Yucatan which is believed to have caused a planet wide winter which destroyed the dinosaurs about 65 million years ago. Most meteors cause only localized damage. Scientists report the Younger-Driest climatic cooling event. One theory is the Clovis Commet because of its impact on Native Americans. An unknown event appears to have occurred in 535 AD. There are widspread reports of skies darkening supported by ice cores and tree rings. It is unclear what hit earth and where. Some scientisrs sugget the Gulf of Carpinteria off northern Australia. The Tunguska event in Siberia is believed to have been a comet impact (1908). The local impact was devestating. A Russian reader writes, "Tanguska still has the scares of the comet's impact. It looks like a terrible battle took place there despite the fact it has been 100 years since the incident."

Types of Events

Astronomical events have the potential of causing huge environmrntal damage. This is because they are so powerful uncommon. Life evolves to normal environmental conditions. These events can abruptly change such conditions. A collpsing nova has the potential of emiting a burst of energy in the form of X-rays which even from the great distances involved could whipe out all life on earth. Such an event is, however, highly unlikely. Much more common are meteors and comets striking earth. Depending the size of the object, these events can have a massive climatic event. Most meteors are small shooting stars which are vaporized in the atmosphere. Large meteors have struck the planrent. Comets can also have disatrous impacts. There have beem much larger events. A much more common astronomical event is sun spots which can have significant climatic impacts.

Specific Events

Researchere have identified several different astronomica events over time. Much of the geological and climatic evidence is fairly conclusive that something happened. Much more controtoversial is just what happened. These event are of course in addition to volcanic events which hd climate imacts.

Chicxulub event (65 million years ago

The best known is the Chicxulub event off Yucatan which is believed to have caused a planet wide winter which destroyed the dinosaurs about 65 million years ago. Most meteors cause only localized damage.

Clovis comet (12,000 BC)

Scientists report the Younger-Driest climatic cooling event. One theory is the Clovis Commet because of its impact on Native Americans. Some scientists believe that it was responsible for the disappearancr of the Clovis culture.

Constantine's meteor (312 AD)

The Roman Emperor Constantine saw a sign in the sky before the Battle of Milvian Bridge‎ (312). He saw this as a heavenly signal and had his men paint Christian crosses on their shields. He would subsequetly enbrace Chrisianity and issue the Edict of Milan which legalized the practice of Christianity (313).

Unknown event (535 AD)

An unknown event appears to have occurred in 535 AD. There are widspread contemporary reports of skies darkening which affected harvests and crop yields. And there is scientific evidnce (ice cores and tree rings) support the facrt that a major event did occur. It is unclear what hit earth and where. Some scientists sugget the Gulf of Carpinteria off northern Australia. This would explain the absence of any written record. The resulting climatic event may have been a factor in the disappeance iof the alreqdy weakened Roman Empire.

Tunguska event (1908 AD)

The Tunguska event in Siberia is believed to have been a comet impact (1908). The local impact was devestating. A Russian reader writes, "Tanguska still has the scares of the comet's impact. It looks like a terrible battle took place there despite the fact it has been 100 years since the incident." It may have been a comet which resulted in an airburst rather than a ground impact. This event was apparently not large enough to have a global climatic impact, but it certainly had a massive localized impact.








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Created: 8:44 PM 12/16/2010
Last updated: 12:52 AM 8/13/2012