Inspired by a post on Universe Today by Nancy Atkinson: 1908 Tunguska Event Caused by Comet, New Research Reveals
Long the subject of debate, with various theories ranging from meteorite impact to a comet to a flying saucer’s sudden engine meltdown, there’s actually strong evidence that the 1908 “Tunguska Event” was likely caused by the explosion of a comet in the upper atmosphere.
This idea has been suggested before, and is now supported by Cornell University engineering professor Michael Kelly’s study of – strangely enough – the space shuttle’s exhaust plumes and their effect on high-atmosphere cloud formation.
To those not familiar with the Tunguska Event, something exploded or impacted in the remote area of Russia on June 30, 1908, flattening the forest in an 830-square-mile area, but leaving no visible crater or other obvious sign of what caused the event. Nearby residents reported the sound of a massive explosion, but that’s about it. Whatever it was, the devastation it caused was extensive and undeniable.
It has been estimated that the blast was equivalent in power to 1,000 Hiroshima-sized detonations.
Michael Kelly noted that high-altitude clouds, called noctilucent clouds (NLCs) commonly form after the entry of the space shuttle into the atmosphere. These clouds tend to reflect light from the sun long into the night, and were particularly visible on July 1, 1908, one day after the Tunguska event. In fact it was noted that many cities across Europe experienced unusually bright nights. The reflective clouds are made up of ice particles, and may have been caused by massive amounts of water vapor scattered into the cold upper atmosphere from the vapor trail and explosion of a comet, which are typically made of rock and water ice.
See images of NLCs made by the shuttle Atlantis’ launch in 2007 here.
Made up of ice formed on the surface of exhaust and dust particles, noctilucent clouds occur only at high altitudes. The researchers believe that water vapor discharged into the atmosphere by a comet’s icy center was caught up in a vortex of immense energy in a process called two-dimensional turbulence, traveling at speeds of nearly 300 feet per second—which explains why the clouds formed thousands of miles away. “It’s like solving a murder mystery,” says Kelley. “We were finishing a puzzle. The pieces were there, but we put them together.” (Source: Cornell Alumni Magazine)
The comet theory is also supported by the obvious lack of an impact crater…an icy comet would have exploded high in the atmosphere, its ice rapidly boiling and expanding upon entry, and although the shockwave would have been – was – extensive and devastating, there was little left to strike the ground. Anything that was left likely disappeared into the soft peat bogs of the Siberian tundra.
But despite the association with NLCs it’s still not known exactly what to blame for the 1908 event—comet or asteroid. Although continuing research over the years has unearthed evidence for both (with some scientists quite strongly asserting their own findings as conclusive) nothing as yet has proven to be a true “smoking gun” for either option and every finding seems to quickly get its fair share of detractors.
Regardless of an origin of comet or asteroid—or something else entirely—the Tunguska Event has been a staple of pop science enigma for decades and probably will be for many more to come.
ADDED 2/4/11: Here’s some more articles on the event from “bad” astronomer Phil Plait:
How Often Does a Tunguska Event Happen?
I recommend you to read a book “The Tunguska Mysery”, by Vladimir Rubtstev, than you will find out that comet snd asteroid hypotheses are bullshit.
i think its due to crash of UFO
I don’t understand why Zlobin could not find the two basic instruments used to investigate the ~60,000 meteorites stored in the world collections. Most of them originates from asteroids (because their trails upon atmospheric entry is typical of fragments ejected from asteroids and not from comets). And about 200 and 10 of then, originate from the Moon and Mars, respectively (this last number of 10 has to be further checked).
These 2 instruments are:– the electron microprobe, to characterize the chemical composition of major elements in a rock, and; — the polarizing optical microscope, to characterize the mineralogical composition of thin sections of a rock, and which was used in Russia at least since 1860!. These basic tools exists in Russia, in particular at the Vernadsky Institute in Moscow, where the Russian lunar samples from 3 of the Luna missions are preserved, and that I visited several times.
About 84% of the meteorites are stony meteorites with a highly typical chondritic composition. Next, what do we expect from comets. About 20% of their mass is made of dust grains, that are captured on the Earth as micrometeorites still showing …a chondritic composition.. and about 30% of them have been melted upon atmospheric entry and collected as highly typical cosmic spherules, still showing a…chondritic composition. They have been collected in the 1970’s by dragging a huge magnet in deep sea sediments. Was a strong magnet dragged around the site of the Tugunska explosion?
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