[meteorite-list] Acid Rain Traces Support Meteor Theory For 1908 Tunguska Blast

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Sat, 5 Jul 2008 22:02:16 -0700 (PDT)
Message-ID: <200807060502.WAA15594_at_zagami.jpl.nasa.gov>

http://www.spacedaily.com/reports/Acid_Rain_Traces_Support_Meteor_Theory_For_1908_Tunguska_Blast

Acid Rain Traces Support Meteor Theory For 1908 Tunguska Blast
RIA Novosti)
July 01, 2008

International researchers investigating the Tunguska Event, an explosion
exactly 100 years ago in central Siberia, say acid rain traces in the
region back up the theory that the blast was caused by a meteorite.

On June 30, 1908, an explosion equivalent to between 5 and 30 megatons
of TNT occurred approximately 7-10 km (3-6 miles) above the Podkamennaya
Tunguska River in a remote Siberian region.

"Extremely high temperatures occurred as the meteorite entered the
atmosphere, during which the oxygen in the atmosphere reacted with
nitrogen causing a build up of nitrogen oxides," one of the authors of
the joint research, Natalia Kolesnikova, told RIA Novosti.

Kolesnikova said a similar impact 66 million years ago wiped out a
significant portion of life on Earth, including the dinosaurs.

The Tunguska blast flattened 80 million trees, destroying an area of
around 2,150 sq km (830 sq miles). However, despite the shockwaves being
detected as far away as the United Kingdom, the Tunguska Event went
largely unnoticed, eclipsed by global events leading up to WWI, the
Russian Revolution and subsequent civil war.

If the explosion had occurred some 4 hours and 47 minutes later, due to
the Earth's rotation it would have completely destroyed the then Russian
imperial capital of St. Petersburg.

It took almost 20 years, until 1927, before a research expedition led by
Leonid Kulik, a leading meteorite expert at the Academy of Sciences,
first managed to visit the remote Siberian region and see the awesome
destruction caused by the blast, and to take witness statements from
locals living in the area.

It was assumed that a huge meteorite had hit the area, although Kulik
failed, during his research in Siberia, to find an obvious crater.

In 1930, a British astronomer suggested the blast could have been caused
by a small comet, composed of ice and dust, which would have been
vaporized on impact with the Earth's atmosphere.

The research carried out by the Moscow State Lomonosov University,
Italy's Bologna University and Germany's Center for Environmental
Research in Leipzig backs up the most likely theory of a meteor explosion.

However it is unlikely to put a stop to speculation on theories ranging
from alien attacks, UFOs, antimatter, doomsday events and black holes.
Received on Sun 06 Jul 2008 01:02:16 AM PDT