tunguska fallen treesWikimedia CommonsTunguska

A 150-foot wide asteroid is expected to make a record-close — but safe — flyby of Earth Friday afternoon. 

Although there is no chance that asteroid 2012 DA14 will smash into our planet (coincidentally a meteorite exploded over Russia Friday morning), scientists say it's about the same size as the one that hit Siberia more than 100 years ago on June 30, 1908.  


The historic explosion happened in Tunguska, a remote forest area in the middle of Siberia.

The blast had the power of 15 megatons of TNT, roughly a thousand times that of the atomic bomb dropped on Hiroshima Japan. The event was so powerful that it was felt and heard a thousand miles away.

Locals believed the blast was supernatural, caused by a god that was punishing people for their wickedness.

Scientists, on the other hand, believed it was a meteor.

Here's Where It Gets Weird

Twenty years passed before the first Russian scientists went to the site to investigate.

If it was a meteor, there would be a crater and meteorite fragments.

However, there was no crater. And there were no fragments.

In fact, at the epicenter of the explosion was a grove of untouched, fully grown trees.  Surrounding that tiny grove was around 800 square miles of leveled trees.

The blast had the hallmarks of an atomic bomb-like explosion. However, no scientific progress had been made in the area of nuclear weapons until the 1930s, more than two decades after the event.

Two Theories

Scientists believe that a football field-sized, solid ice chunk of a comet entered Earth's atmosphere. When it encountered Earth's intense atmospheric pressure, it immediately exploded miles above the forest. Because it was made of ice, it left no extraterrestrial evidence.

Others believe it was caused by something much smaller: A nuclear-powered alien spaceship that crashed into the Earth.

A hundred years later, neither side seems to have fully convinced the other camp.