A Year: Day to Day Men: 30th of June

Beauty in a Form

June 30, 1908 is the date of the Tunguska Event in Siberia.

The Tunguska event was a large explosion that occurred near the Stony Tunguska River In Krasnoyarsk Krai, Russia on the morning of June 30, 1908. This event is the largest impact event on Earth in recorded history. The explosion over the Easter Siberian tiaga, a very large ecoregion of forests and wildlife, flattened 770 square miles of forest, yet caused no known human casualties.

The explosion is generally attributed to the air burst of a meteoroid, It is classified as an impact event, though no impact crater has been found. The object is thought to have disintegrated at an altitude of 3 to 6 miles rather than to have hit the Earth’s surface. Studies have yielded estimates of the meteoroid’s size from 200 to 600 feet. Estimates of the energy of the downward airburst range from three to five megatons of TNT (three to five million tons). The explosion knocked down some 80 million trees over the affected area.

Natives and Russian settlers in the hills north-west of Lake Baikal observed a column of bluish light, nearly as bright as the sun, moving across the sky. About ten minutes later, there was a flash and a sound similar to artillery fire. Eyewitnesses closer to the explosion site reported the sound moved from the east to the north. The sounds were accompanied by a shock wave that knocked people off their feet and broke windows hundreds of miles away.

The explosion registered at seismic stations across Euroasia; in some places, the shock wave registered equivalent to an earthquake of 5.0 magnitude. Fluctuations in atmospheric pressure were detected in Great Britain. Over the next few days, night skies in Asia and Europe glowed. The theory for this was light passing through high-altitude ice particles that had formed at extremely low temperatures. Suspended dust particles caused a month-long decrease in atmospheric transparency, according to observers at the Mount Wilson Observatory in Los Angeles County, California.

It is believed that the passage of the asteroid through the atmosphere caused pressures and temperatures to build up to a point where the asteroid abruptly disintegrated in a huge explosion. The destruction would have to have been so complete that no remnants of substantial size survived, and the material scattered into the upper atmosphere during the explosion would have caused the glowing skies.