Scientists have warned that relatively small asteroids could pose a much bigger threat to mankind than first thought. Previous models on asteroid strikes were based on data from stationary nuclear detonations in earth's atmosphere. But a new computer simulation of an exploding asteroid in motion has revealed that smaller objects can produce more damage, as the energy from the blast is funnelled towards the ground rather than spreading out in all directions. On the 30th of June, 1908, an asteroid exploded near the Tunguska river in Siberia. The explosion lit up the sky and levelled around 1,250 square miles of forest. 

Quote: "At around 7:15 a.m., Tungus natives and Russian settlers in the hills northwest of Lake Baikal observed a column of bluish light, nearly as bright as the Sun, moving across the sky. About 10 minutes later, there was a flash and a loud knocking sound similar to artillery fire that went in short bursts spaced increasingly wider apart. Eyewitnesses closer to the explosion reported the sound source moving during each barrage, east to north. The sounds were accompanied by a shock wave that knocked people off their feet and broke windows hundreds of miles away. The majority of eyewitnesses reported only the sounds and the tremors, and not the sighting of the explosion. Eyewitness accounts differ as to the sequence of events and their overall duration.

Scientists originally believed the Tunguska asteroid to be around 100 feet in diameter with a mass of 560,000 metric tonnes. But based on this new data, scientists estimate a smaller object of around 65 feet in diameter and around 140,000 metric tonnes could have produced the same devastation.

Quote: "The space rock is thought to have blown up above the surface, only fragments possibly striking the ground. Now new supercomputer simulations suggest "the asteroid that caused the extensive damage was much smaller than we had thought," Boslough said. Specifically, he and his colleagues say it would have been a factor of three or four smaller in mass and perhaps 65 feet (20 meters) in diameter. The simulations run on Sandia's Red Storm supercomputer — the third fastest in the world — detail how an asteroid that explodes as it runs into Earth's atmosphere will generate a supersonic jet of expanding superheated gas. This fireball would have caused blast waves that were stronger at the surface than previously thought.

In a recent report in the New Scientist journal, Dr Mark Boslough warned of the danger that the Tunguska event could be repeated, only this time over a dense population centre. He said, "It is becoming clear previous models are not right. If one of these events hit an area of high population density, it could kill a million people". Just this past week an asteroid named 2007 XB23 passed within 65,000 miles of earth, or around a third of the distance between the moon and the earth. It's estimated size is just 10-23 metres, but if such an asteroid were to impact in a major population centre, you can just imagine the chaos that would ensue. The Bible seems to indicate that the earth will be struck by a devastating meteor shower early on in the tribulation period. One third of earth's vegetation will be destroyed in the initial impact. That's if the hail and fire mentioned in these verses are from outer space. A large asteroid will strike the sea, destroying the ships and a third part of sea life. The world watched in awe as Shoemaker Levi 9 struck Jupiter over a period of days. One day they will watch in terror as an asteroid strikes the earth. Isaiah foretells that one day, the earth will reel to and fro like a drunkard, and every island will be moved out of its place (Isaiah 24:20). Oh that men would repent of their sins, before these calamities come upon the earth.

Revelation 8:7-9
The first angel sounded, and there followed hail and fire mingled with blood, and they were cast upon the earth: and the third part of trees was burnt up, and all green grass was burnt up. And the second angel sounded, and as it were a great mountain burning with fire was cast into the sea: and the third part of the sea became blood; And the third part of the creatures which were in the sea, and had life, died; and the third part of the ships were destroyed.

Isaiah 24:17-20
Fear, and the pit, and the snare, [are] upon thee, O inhabitant of the earth. And it shall come to pass, [that] he who fleeth from the noise of the fear shall fall into the pit; and he that cometh up out of the midst of the pit shall be taken in the snare: for the windows from on high are open, and the foundations of the earth do shake. The earth is utterly broken down, the earth is clean dissolved, the earth is moved exceedingly. The earth shall reel to and fro like a drunkard, and shall be removed like a cottage; and the transgression thereof shall be heavy upon it; and it shall fall, and not rise again.

Source Wikipedia, Space, Scotsman