It was an energetic event that occurred over Tunguska, but what caused it? (Don Davis)

Was the Tunguska Fireball a Comet Chemical Bomb?

Article Updated: 24 Dec , 2015

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[/caption]Over a century ago, on June 30th, 1908 a huge explosion detonated over an unpopulated region of Russia called Tunguska. It is probably one of the most enduring mysteries of this planet. What could cause such a huge explosion in the atmosphere, with the energy of a thousand Hiroshima atomic bombs, flattening a forest the area of Luxembourg and yet leaving no crater? It is little wonder that the Tunguska event has become great material for science fiction writers; how could such a huge blast, that shook the Earth’s magnetic field and lit up the Northern Hemisphere skies for three days leave no crater and just a bunch of flattened, scorched trees?

Although there are many theories as to how the Tunguska event may have unfolded, scientists are still divided over what kind of object could have hit the Earth from space. Now a Russian scientist believes he has uncovered the best answer yet. The Earth was glanced by a large comet, that skipped off the upper atmosphere, dropping a chunk of comet material as it did so. As the comet chunk heated up as it dropped through the atmosphere, the material, packed with volatile chemicals, exploded as the biggest chemical explosion mankind had ever seen…

12,000 years ago, a large object smashed into North America, causing global destruction. Dust and ash was released into the atmosphere, triggering global cooling and possibly causing the extinction of a number of large mammals around this time. The Tunguska event was of a similar energy to that catastrophic impact, but fortunately for us, Tunguska had a benign effect on the world. It simply exploded high in the atmosphere, flattened a region of Russia and vaporized.

Significantly, the energy of the chemical explosion is substantially lower than the kinetic energy of the body,” says Edward Drobyshevski of the Russian Academy of Sciences in St Petersburg, who has published his research into the Tunguska event. The fact that the Tunguska explosion energy is lower than what is expected of the kinetic energy of an object that hit the Earth from space is key to his work. Drobyshevski therefore concludes that the event must have been caused not by an asteroid or whole comet, it was actually caused by a fragment of comet material that fell off as the main cometary body skipped off the Earth’s upper atmosphere. This means that the Earth was hit on a tangent and the fragment dropped comparatively slowly toward the surface.

Sounds reasonable so far, but how did the fragment explode? Using our new understanding as to what chemicals comets contain, Drobyshevski surmises the fragment was rich in hydrogen peroxide. This is where the magic happened. The explosion was not due to a rapid release of kinetic energy, it was in fact a hydrogen peroxide bomb. As the fragment descended, it heated up. As the reactive chemicals in the material got hot, they explosively disassociated to form oxygen and water, ripping the fragment apart. The Tunguska event was therefore a huge chemical bomb and not a “regular” comet-hits-Earth impact.

An interesting study. Not content with dropping asteroids on our planet, the Universe has started throwing hydrogen peroxide explosives at us too. Whatever next?

Source: The Physics arXiv Blog

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Olaf
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Olaf
March 27, 2009 1:30 PM

Sounds nice in theory but there is no observable evidence that a comet was spotted at that time.

Even if it was a tiny comet, it should have been visible for astronomers long before it skimmed the Earth, and even if it was not visible before, the moment it skimmed Earth’s atmosphere it would light up for thousands of miles visible for a lot of people and visible for many days after it moved away from Earth because of the gasses it lost that light up.

Total Science
Member
March 27, 2009 2:00 PM
It is best to refer to eyewitness observation. Sibir Newspaper, July 2, 1908: On the 17th of June, around 9 in the AM, we observed an unusual natural occurrence. In the N Karelinski village (200 verst N of Kirensk) the peasants saw to the North-West, rather high above the horizon, some strangely bright (impossible to look at) bluish-white heavenly body, which for 10 minutes moved downwards. The body appeared as a “pipe”, i.e. a cylinder. The sky was cloudless, only a small dark cloud was observed in the general direction of the bright body. It was hot and dry. As the body neared the ground (forest), the bright body seemed to smudge, and then turned into a giant… Read more »
Jon Hanford
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Jon Hanford
March 27, 2009 2:22 PM

What was wrong with the old airburst theory that posited that atmospheric pressure built up sufficiently to cause the interloper to burst in midair, creating a huge pressure wave that flattened thousands of miles of tundra forest? If a chunk of an object coming in tangentially to earth’s surface were to lose a piece that eventually exploded in the air, would not the felled trees not reflect this asymmetric blast wave by having an extremely ellipsoidal blast pattern? I think Occam’s razor may say otherwise.

James
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James
March 27, 2009 2:58 PM

If this was a fragment would we not be able to calculate where the original object would be now?

Especially if we can assume this object came out of the sun and no direct observations where possible until it was on top of the Earth.

Maxwell
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Maxwell
March 27, 2009 3:10 PM

As we dont know the original angle that the comet hit, and what exact direction it came from, and its mass, its almost impossible to say where it is now. Too many unknown variables.

Maxwell
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Maxwell
March 27, 2009 3:33 PM

Jon: Its not much of a stretch to think the scientist involved in this work hasnt thought of that, in fact it is probably one of the reasons for his work..the current Theories do not fully explain the evidence . The scientist who did this study knows more about this event ( details ) than us laypeople…he stated that he has a Theory that better explains the event than current theories. Remember this is published, *peer reviewed* work, its pretty much guaranteed that ‘occams razor’ has been liberally applied.

Olaf
Member
Olaf
March 27, 2009 3:40 PM

Oil these are witnesses of the part that fell down, not the part that skilmmed the earth and moved away after the explosion.

A comet this close to the solar system will have a tail and will be visible for many days/weeks before and after the event and seen by astronomers in a big part of the world.

Sili
Member
Sili
March 27, 2009 3:43 PM

12,000 years ago, a large object smashed into North America, causing global destruction. Dust and ash was released into the atmosphere, triggering global cooling and possibly causing the extinction of a number of large mammals around this time.

Hasn’t this claim been pretty much debunked lately? At least it comes across as distinctly non-mainstream.

Layman
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Layman
March 27, 2009 4:41 PM

Oillmastery- good job on digging up those eyewitnesses- I had never read those before-

There have been several good programs on the Science channel concerning the subject and the ideas are many- Meteors-comets- gas escaping from the ground out of an extinct volcano- and one scientist who still believes that it may have been an alien space ship that exploded over the area- so far no little green men have been found.

I could speculate as to what your eye witness observations conclude but I am afraid that my answers would be naive.

So lets hear it- What do you think caused the multiple explosions.

R2K
Guest
March 27, 2009 5:03 PM

Nahhhh….

Olaf
Member
Olaf
March 27, 2009 5:17 PM

You know, this is one of the few things that could be explained by plasma and an electric jolt because of some magnetic reconnection after it has been twisten too much and snaps. LOL

Trippy
Member
Trippy
March 27, 2009 5:35 PM
Olaf: As far as before goes, it is entirely possible that it’s trajectory meant that from the earths perspective it was close to the sun most of the time – the perfect examples of this being most of the Kreutz Sun Grazers, and specifically, the Great Eclipse Comet of 1882 X/1882 K1). MAny of the Kreutz sun grazers follow trajectories that, for most of the year mean their invisible – which only really leaves the question of why wasn’t the parent body spotted after the collision, and I think ONE POSSIBLE explanation to this is that if it was a volatile rich fragment in a largely dusty body (which to some extent could appear to be supported by… Read more »
Trippy
Member
Trippy
March 27, 2009 5:55 PM

To follow up my previous post, it has been previously noted that in order for a cometary fragment to penetrate that far into the atmosphere, it would had to have been an extinct comet with a stony mantle.

What i’d like to know is if this researcher considered Lake Cheko.

mang
Member
mang
March 27, 2009 6:31 PM

I had thought earlier Russian researchers had identified a butterfly shaped blast pattern. Wouldn’t that suggest a trajectory?

The 12,000 year old strike theory relates to the Clovis culture. See http://www.universetoday.com/2008/07/07/exploding-asteroid-theory-gains-evidence/

Marco
Member
March 27, 2009 6:58 PM

The picture accompanying this article is one of the coolest on this site in a long time.

There is so little evidence about the 1908 event that a scientist could posit just about anything that sounds remotely resonable. In cases like that, I tend toward normal explanations rather than exotic ones. A large bolide makes more sense that a molotov cocktail from space.

Aqua
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Aqua
March 27, 2009 8:15 PM

Cometary or asteroidal impact over N.A. 12,000 BCE eplains so many things its hard to ignore the possibility.

Surak
Member
Surak
March 27, 2009 10:03 PM
The event 12,000 years ago was far more severe, spreading microdiamonds over a large part of north america, There’s really no comparison. Plenty of nuclear bombs have been detonated that were far more powerful than tunguska … yet far far weaker than the event 12,000 years ago. As for Olaf … Not all comets are as splendid as you imagine … and in 1908, there wasn’t always someone looking in the right place at the right time. The object hit around 9am in the summer … during the DAYTIME. It may not have even been visible at night! A large primary object that dropped a fragment and skipped away is not even necessary its just another idea. Too… Read more »
Sir Arthur Wellesley
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Sir Arthur Wellesley
March 27, 2009 11:58 PM

Those are some good reports Oils, I too have never read them.

I guess they really just add to the mystery surrounding this event. Nevertheless fascinating!

Sir Arthur Wellesley
Member
Sir Arthur Wellesley
March 27, 2009 11:59 PM

Those are some good reports Oils, I to have never read them.

I guess they really just add to the mystery surrounding this event. Nevertheless fascinating!

Emma What's On?
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Emma What's On?
March 28, 2009 1:39 AM

What? I thought it was Hancock and his supposedly wife fighting in that region before Hancock lost his memories?

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