Space shuttle science shows how 1908 Tunguska explosion was caused by a comet

Jun 24, 2009
The Tunguska Event--100 Years Later
Trees felled by the Tunguska explosion. Credit: the Leonid Kulik Expedition.

The mysterious 1908 Tunguska explosion that leveled 830 square miles of Siberian forest was almost certainly caused by a comet entering the Earth's atmosphere, says new Cornell University research. The conclusion is supported by an unlikely source: the exhaust plume from the NASA space shuttle launched a century later.

The research, accepted for publication (June 24, 2009) by the journal , published by the American Geophysical Union, connects the two events by what followed each about a day later: brilliant, night-visible clouds, or noctilucent clouds, that are made up of ice particles and only form at very high altitudes and in extremely .

"It's almost like putting together a 100-year-old murder mystery," said Michael Kelley, the James A. Friend Family Distinguished Professor of Engineering at Cornell who led the research team. "The evidence is pretty strong that the Earth was hit by a comet in 1908." Previous speculation had ranged from comets to meteors.

The researchers contend that the massive amount of water vapor spewed into the atmosphere by the comet's icy nucleus was caught up in swirling eddies with tremendous energy by a process called two-dimensional turbulence, which explains why the noctilucent clouds formed a day later many thousands of miles away.

Noctilucent clouds are the Earth's highest clouds, forming naturally in the mesosphere at about 55 miles over the polar regions during the summer months when the mesosphere is around minus 180 degrees Fahrenheit (minus 117 degrees Celsius).

The space shuttle exhaust plume, the researchers say, resembled the comet's action.

A single space shuttle flight injects 300 metric tons of water vapor into the Earth's thermosphere, and the water particles have been found to travel to the Arctic and Antarctic regions, where they form the clouds after settling into the mesosphere.

Kelley and collaborators saw the noctilucent cloud phenomenon days after the space shuttle Endeavour (STS-118) launched on Aug. 8, 2007. Similar cloud formations had been observed following launches in 1997 and 2003.

Following the 1908 explosion, known as the
Tunguska Event, the night skies shone brightly for several days across Europe, particularly Great Britain -- more than 3,000 miles away.

Kelley said he became intrigued by the historical eyewitness accounts of the aftermath, and concluded that the bright skies must have been the result of noctilucent clouds. The comet would have started to break up at about the same altitude as the release of the exhaust plume from the following launch. In both cases, water vapor was injected into the atmosphere.

The scientists have attempted to answer how this water vapor traveled so far without scattering and diffusing, as conventional physics would predict.

"There is a mean transport of this material for tens of thousands of kilometers in a very short time, and there is no model that predicts that," Kelley said. "It's totally new and unexpected physics."

This "new" physics, the researchers contend, is tied up in counter-rotating eddies with extreme energy. Once the got caught up in these eddies, the water traveled very quickly -- close to 300 feet per second.

Scientists have long tried to study the wind structure in these upper regions of the atmosphere, which is difficult to do by such traditional means as sounding rockets, balloon launches and satellites, explained Charlie Seyler, Cornell professor of electrical engineering and paper co-author.

"Our observations show that current understanding of the mesosphere-lower thermosphere region is quite poor," Seyler said. The thermosphere is the layer of the atmosphere above the mesosphere.

More information: The paper is available at: www.agu.org/journals/gl/papersinpress.shtml

Source: Cornell University (news : web)

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User comments : 15

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LariAnn
1.3 / 5 (3) Jun 24, 2009
I wonder if "bright skies" can be the same as noctilucent clouds. I've seen noctilucent clouds and I would never refer to their sight as "bright skies". I would call them "glowing clouds". I think we have to give observers some kind of credit for having intelligence enough to know the difference between a "bright sky" and a "glowing cloud". I also wonder how a ball of ice can explode so violently as to level 830 square miles of trees. If this can happen, why use nuclear weapons? Just hurl large chunks of ice from outer space at the enemy!!
Edylc
1 / 5 (1) Jun 24, 2009
Is this the one that some say Tesla did?
defunctdiety
1 / 5 (2) Jun 24, 2009
I also wonder how a ball of ice can explode so violently as to level 830 square miles of trees. If this can happen, why use nuclear weapons? Just hurl large chunks of ice from outer space at the enemy!!


I think I may have heard something once about a theoretical weapon that would basically drop very large rods of metal from a "weaponized" satellite, to try and achieve something like this.
googleplex
4.3 / 5 (4) Jun 24, 2009
LariAnn - the issue with ice hurling is getting a big enough piece and throwing it at comet velocity.

Details
=======
The energy released from the impact of a comet is 1/2mv^2 (half m v squared). The relative velocity of the comet to the earth is very high. Then you square it and you get a big number. Then multiply it by its mass (in kg) and you quickly get energy of a magnitude comparible to kilo tons of TNT explosives i.e. small nuke.

Math
====
Velocity of comet approx. =100,000 km/hr =28,000 m/s
(based on halleys comet)
Mass approx. = 10^14 kg
(based on Comet 9P/Tempel 1 aka "deep impact")
Energy = (28 x 10^17)^2 Joules
1 Megaton of TNT = 4 x 10^15 J
Energy = (700)^2 MegaTons TNT.
Biggest nuke tested (Tsar Bomb) approx = 100 megaton
Ricochet
1 / 5 (1) Jun 24, 2009
In other words, "Big badda boom"
NickFun
1 / 5 (2) Jun 24, 2009
Of course, this hypothesis does not rule out the possibility of a UFO either. Conspiracy theorists can relax!
LuckyBrandon
1.5 / 5 (2) Jun 24, 2009
lariann-look at the photos of the relatively small comet schumaker-levy breaking into smaller fragments and impacting jupiter, creating holes in its atmosphere many times the size of earth. these were relatively small fragments, however, much larger than the tunguska event.

i think a good analogy would be jumping out of a plane at 10,000 ft without a parachute into a lake. water flows around you when you swim right, yet its as hard as concrete when you hit it at terminal velocity.

in other words, even a liquid ball of water hurling into our atmosphere would likely have a similar effect.





defunct-yes at one point there was a proposal for a satellite weapon to launch rockets or even simple metal rods from space. however, its against international treaty and always will be until the "Federation" becomes reality on our planet :)
Vlasev
1 / 5 (1) Jun 25, 2009
I also wonder how a ball of ice can explode so violently as to level 830 square miles of trees. If this can happen, why use nuclear weapons? Just hurl large chunks of ice from outer space at the enemy!!
















I think I may have heard something once about a theoretical weapon that would basically drop very large rods of metal from a "weaponized" satellite, to try and achieve something like this.




comments travel at some speed. This is tremendous amount of energy, and it has to be released upon entry/collision.



kinetic-energy weapons, rods from gods :http://www.popsci...rods-god



Tangent2
1 / 5 (2) Jun 25, 2009
"I also wonder how a ball of ice can explode so violently as to level 830 square miles of trees."

I'm with you guys on this one. These researchers are just saying they made a connection with some clouds.. that is all. They probably didn't even run any simulations to see if it could possible be a comet and what the size of it would need to be to devastate such a large area. In the end, the only thing to be gleamed from this article is that the researches believe there was a large amount of water involved in the event, that is all.
TexasMeteorites
1 / 5 (1) Jun 25, 2009
There had been an argument or difference of opinion for sometime regarding the impacting object, although it was long ago settled by the Russians who concluded by 1980 that it was a comet and not an Asteroid, a type of stony meteorite.

Ricochet writes:
The energy released from the impact of a comet is 1/2mv^2 (half m v squared). The relative velocity of the comet to the earth is very high. Then you square it and you get a big number. Then multiply it by its mass (in kg) and you quickly get energy of a magnitude comparible to kilo tons of TNT explosives i.e. small nuke.

This does not even come into play because the solid object (comet) never impacted the terrestrial surface but rather exploded some distance above it's likely landing spot if it were an asteroid. We know this because the Russian study provided evidence that with intense damage to the landscape, but no crater was found. So what caused the multi megatonne explosion? Embedded in the ice crystals and in the crystalline silicate gains the comet contained highly explosive volatile gases such as methane which ignited under the intense pressure from atmospheric entry. All of the gas gas bubble ignited almost simultaneously in a chain reaction causing a massive explosion; displacement of huge volumes of air and micro crystalline cometary particles which felled the forest.
You can see what crystalline cometary grains look like at this link.
http://www.bccmet...ge4.html

Stellar grains here.
http://www.bccmet...ge3.html
jonnyboy
1 / 5 (3) Jun 25, 2009
There had been an argument or difference of opinion for sometime regarding the impacting object, although it was long ago settled by the Russians who concluded by 1980 that it was a comet and not an Asteroid, a type of stony meteorite.

This does not even come into play because the solid object (comet) never impacted the terrestrial surface but rather exploded some distance above it's likely landing spot if it were an asteroid. We know this because the Russian study provided evidence that with intense damage to the landscape, but no crater was found. So what caused the multi megatonne explosion? Embedded in the ice crystals and in the crystalline silicate gains the comet contained highly explosive volatile gases such as methane which ignited under the intense pressure from atmospheric entry. All of the gas gas bubble ignited almost simultaneously in a chain reaction causing a massive explosion; displacement of huge volumes of air and micro crystalline cometary particles which felled the forest.

You can see what crystalline cometary grains look like at this link.

http://www.bccmet...ge4.html


I suppose you believe that getting hit by a frozen turkey does more damage than getting hit by a thawed one.
Ricochet
not rated yet Jun 26, 2009
Ricochet writes:



The energy released from the impact of a comet is 1/2mv^2 (half m v squared). The relative velocity of the comet to the earth is very high. Then you square it and you get a big number. Then multiply it by its mass (in kg) and you quickly get energy of a magnitude comparible to kilo tons of TNT explosives i.e. small nuke.




Actually, that was Googleplex that wrote that...
designmemetic
not rated yet Jun 27, 2009
cool. I don't suppose anyone took pictures of the sky back then. Too bad, you might use the photos to test models and refine size and speed of comet. Or alternatively refine size and speed of winds at in that part of the atmosphere
austux
1 / 5 (1) Jun 28, 2009
I also wonder how a ball of ice can explode so violently as to level 830 square miles of trees. If this can happen, why use nuclear weapons?
Since a comet is much plasma & very little solids, I suspect that the plasma people would have a fair bit to say about that event, & yes, it is indeed nuclear (even if not deployed as a weapon, /cue alien theories here/)
SMMAssociates
not rated yet Jun 28, 2009
"Bright Skies" v.s. "Bright Clouds".... In 1908, most of the world lacked the pervasive night brightness that now moves observatories into the hinterlands....

Just guessing, but I would think that observers then would find even a small increase in "brightness" significant - much less, perhaps, than we can see nowadays without instrumentation.

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