[BenLurkin]

I wonder if disasters like the Tunguska Event are more frequent that we realized. Absence of craters from these kinds of impacts might disguise how often they happen.

[Clay Moore]

There is no reason to think that the Earth had not taken as many hits proportionally as what we can see on the Moon. Yes our atmosphere is going to break up the asteroids more but it should be about the same.

[SunkenCiv]

For a long while it was taught that all of Earth's impact craters formed during the Late Heavy Bombardment, and that all trace of them had been eroded away, because Earth is unique etc. Turns out people just weren't looking for them, now nearly 200 have been identified and studied.

• Have scientists finally found the meteorite which set off the mysterious 1908 Tunguska catastrophe?
• Astronomy Picture of the Day -- Tunguska: The Largest Recent Impact Event
• When Comets Attack: Solving the Mystery of the Biggest Natural Explosion in Modern History
• Toxic Gases Caused World's Worst Extinction
• Russian Scientists In Bid To Solve Tunguska Event
• 100 years on, mystery shrouds massive 'cosmic impact' in Russia
• Planetary science: Tunguska at 100
• Tunguska, A Century Later
• Research: Asteroids pose greater danger
• Sandia supercomputers offer new explanation of Tunguska disaster
• Crater From 1908 Russian Space Impact Found, Team Says (Tunguska)
• Three-tonne meteorite stolen in Russia (rock from Tunguska)
• Crater Could Solve 1908 Tunguska Meteor Mystery
• A possible impact crater for the 1908 Tunguska Event
• Catastrophic Comet Chilled and Killed Ice Age Beasts (and Clovis people)
• Threat of Cometary Impacts may be Underestimated
• Grains Found in Ga. Traced to Asteroid
• Russian scientists claim discovery of alien spaceship wreck in Siberia
• Tunguska, Siberia - Russian scientists claim discovery of alien spaceship
• Russian Researchers Say Debris of Alien Spaceship found in Siberia
• Cosmic Collision May Have Created Hawaii
• Siberia Meteorite Flattens 40 Sq Miles
• Evidence Of Tunguska-Type Impacts Over The Pacific Basin Around The Year 1178 AD
• More Theories on Tunguska
• Cash Plea For Russian Meteor Chasers (Impact Crater)
• Asteroid 'Hit Northern Russia'
• Asteroid detected in a close call with Earth
• What Caused Argentina's Craters?
• Mystery space blast 'solved' [Italian Scientists Solve Mystery of 1908 Siberian Blast]

[gleeaikin]

It is interesting that more and more evidence is piling up to support the hypothesis in Firestone et al.’s book. The article talks of the ice age ending at the time of the Younger Dryas which was then made worse. My understanding is the the ice age was ending around 15 to 18,000 years ago, and that this event/series of events triggered the Younger Dryas. Firestone’s book documents very widespread effects from Canada to our Southwest and even northwestern Europe. My vote would be for more than one impactor. After all, remember how many boloids struck Jupiter a few years ago.

The Carolina Bays are one such phenomenon possibly caused. My guess is that huge blocs of ice were thrown out, skidded to a stop and melted. Lake Michigan appears to have been formed by 2 or 3 impactors whose traces are found underwater. The Clovis culture was decimated as were large numbers of the great mammals.

The Tungusku event was small by comparison. A similar event occurred in the Brazilian jungle several decades later but was somewhat smaller in size. We are only beginning to appreciate the impact of boloid events on our earth and our history. Sunken Civ has brought to our attention the discover of a 2 mile crater in the drained Iraq Marshes whih fell about 4,000 years ago. Was this the cause of the First Intermediate Period in Egypt about that time? Ipuwer records a time of terrible social upheaval and distress in a papyrus. There are also fairly large meteor craters found in Argentina around the same period or perhaps a little earlier. So much to learn, so little time!! But first we have to use our open minds.