What are your theories on the mysterious Tunguska explosion in Siberia?

Question

Researchers theorize that Lake Cheko contains remnants of a space rock that exploded in midair over the Tunguska river in 1908.

http://macrocosm-magbook.blogspot.com/2007/06/tunguska-explosion-may-have-left.html

Answer 1

There are relatively few impact sites available for study and comparison anyway, and the Tunguska site is different from all the others, so almost any crackpot theory goes. Even Arthur C. Clarke thought that it might - just might - have been the explosive destruction of a nuclear-powered alien spaceship.

But an almost-normal stony meteorite, whose unusually shallow trajectory caused it to heat up enough to explode, is not that much different from what has caused other impacts, and it has plausibly been modelled to cause approximately what can be seen at Tunguska, so until some very definite and insoluble discrepancy is shown, that's where all the smart money should be.

Answer 2

"Einstein" posted some interesting answers, but the volcanic origin can be pretty well ruled out as witnesses reported seeing a blue-white object "brighter than the sun" coming down at a nearly vertical angle from the sky just before the blast.

There are no definitive impact craters at the site, but the area was peppered with small craters which would point to some kind of meteoric explosion several thousand feet over the site.

It could not have been a comet, for comets are not dense enough to survive entry into the earth's atmosphere at velocities of about 30-33,000 mph as do meteors.

The best answer is a small nickel-iron asteroid which approached at a high angle and high velocity. Friction from the atmosphere caused internal heating, and any gases trapped inside would have finally erupted causing the whole asteroid to explode. The kinetic energy created by the velocity and mass of the asteroid would have created a monumental explosion, and the shock waves would have followed typical chaos theory in which some areas would be totally devastated and other would be virtually untouched.

Remember also, it was about 20 years after the blast before any scientists visited the site to do any research.

My bet is on a small nickel-iron or stony asteroid.

Answer 3

Tunguska Theories

Answer 4

I Personally am of The Opinion That, it was Caused By An artificial event By Extra terrestrials as The Blast wave Propagation Was Vertically Downwards over The entire Area Unlike A Blast Caused By Natural Explosions Etc. Comets Or Meteorites Do Not explode In The Like Manner

Answer 5

The biggest space impact suffered by Earth in modern times is the Tunguska event, when an impact put down more than 2,000 sq km of forest near the Tunguska River (Siberia) on 30 June 1908. Could it have been caused by a comet or asteroid blasting in the atmosphere with a power similar to 1,000 Hiroshima bombs explosions (20 millions tones of TNT)?

Some researchers actually think that Lake Cheko—located 8 km (5 mi) north-north-west of the epicenter of the event—could fill the crater dug by a rock chunk coming from the space body hitting the ground. "Lake Cheko—though shallow—fits the proportions of a small, bowl-shaped impact crater," said an Italian research team. However, it seems more likely that the lake itself was actually formed by volcanic eruption, not a projectile of extraterrestrial origin.

More than 17 reasons are presented of why the fiery Siberian event of 30 June 1908, near the Stony Tunguska river, was not caused by the impact of a stony asteroid, nor of an (icy) comet, but rather by the volcanic ejection of some 10 Mton of natural gas. There have been many research expeditions attempting to investigate the Tunguska phenomena.

For the volcanic (outflow) interpretation, estimates are presented of the involved mass and kinetic energy of the vented natural gas, of its outflow timescale, supersonic and subsonic ranges, and buoyant escape towards the exosphere. The Tunguska event may well have been the present-day formation of a kimberlite, a type of rock best known for sometimes containing diamonds:

19 REASONS

(1) The fact that in the literature, the comet-versus-asteroid debate is heftily alive rules against both interpretations: an asteroid would have left a trace, whereas a comet would have exploded too high, also would have been discovered weeks before impact.
(2) An impacting body, no matter of what consistency, cannot explain the many (> 12) conical holes in the ground, now lakes, which were formed on that morning. Nor can it explain (3) the dozens of tree stumps lying around without recognizable origin, or (4) the tree stump at the bottom of the drained Suslov hole.
(5) Why does the epicenter lie at the intersection of several fault lines, one of them running towards lake Baikal, and why does it coincide with the Kulikovskii crater, which belongs to the Khushminskii tectono-volcanic complex ? This constellation is reminiscent of kimberlites, as well as (6) the local surface geometry, called 'amphitheater' by Kulik, with the 'Merrill circus' in the middle.
(7) The tree-fall pattern, which should be parallel for a low-inclination infall, is roughly radial. But it follows the valleys, shows islands of survival and islands of destruction, has (8) more than 4 centers (Kulik's airphotographs) and has (9) inverted profiles (Krinov), with undestroyed trees in the valleys, chopped-off tree-tops on the slopes, and felled trees near the hill tops, asking for blasts from below. (10) The 'telegraph poles' near the epicenter require supersonic shock waves; they are reminiscent of the Hiroshima blast wave.
(11) Several eyewitnesses reported a large number of 'barisal guns' before they saw (12) 'columns of fire'; this order of events, and orientation, are expected for a volcanic blowout, not for an impact. (13) They sensed heat in their faces, which is difficult to realize for an impact trail.
(14) The 4 bright nights, straddling the explosive event, require clouds in the thermosphere, reminiscent of volcanic activity like Krakatoa (1883). Such volcanic blowouts have been recently detected in the form of (15) rising 'mystery clouds' seen by airplane pilots, and in the form of (16) 'pockmarks' on large parts of the ocean floor.
(17) All chemical peculiarities found by expeditions were consistent with earthquakes, or 'de-gassings in active tectonic zones'. Remarkably, (18) the 2000 Italian expedition recorded a radiation storm at gamma-rays near lake Cheko, which lasted some four hours.
(19) It is well known to geophysicists that only a small minority of terrestrial craters are of meteoritic origin; most of them were formed by volcanism. Volcanism has many different faces, ranging from hardly noticeable out-gassing through lava flows through burning torches, mud volcanoes and real volcanoes all the way to explosive, supersonic ejections. In all cases, rising natural gas is the primary piston.

Answer 6

I think that a Meteor(s) could have made that.