Things You Probably Didn't Know

[IceWizard]

About The 1908 Tunguska Event







In 1908, the largest asteroid in recorded history exploded above
Tunguska in Siberia, Russia.  We now observe Asteroid Day each year
on June 30, on the anniversary of what’s now known as the Tunguska
explosion. Here are 5 things you didn't know about this famous explosion.




The Explosion Was The Largest In Recorded History

When the blast occurred, witnesses claimed to see something of a fireball or
a bluish light moving across the sky. It was almost as bright as the sun and
was followed by a flash and a sound that mimicked artillery fire. The incredible
sight was accompanied by a powerful shockwave that shattered windows for
hundreds of miles and knocked people off their feet.



No Crater Was Ever Found

A mysterious aspect of the Tunguska event was that no crater was ever found.
But, even without a crater, scientists still categorized it as an impact event.
They now believe the incoming object never struck Earth, but instead exploded
in the atmosphere, causing what’s known as an airburst. This type of atmospheric
explosion was still enough to cause massive damage to the forest in the region.
Scientists determined the object was most likely a stony asteroid approximately
the size of a 25-story building. The asteroid was traveling at a speed of about
33,500 miles per hour and exploded 3 to 6 miles above Earth’s surface.



Decades Passed Before Anyone Could Explain The Event

Due to the size and speed of the asteroid, the explosion released so much energy
that an estimated 80 million trees destroyed, and reindeer were killed for miles
around the blast site. At the time of the explosion, it was difficult for anyone to
reach that remote part of Siberia. It wasn't until almost 20 years later that
Leonid Kulik sled the first Soviet research expedition to investigate the
Tunguska event.



The Cause Of The Event Is Believed To Be From An Asteroid

Scientists and researchers came up with all sorts of hypotheses regarding what
sparked the Tunguska explosion throughout the years.  Some theories were very
colorful, such as the notion that the Earth was encountered by an alien spacecraft
or that a mini-black-hole or a particle of antimatter was the culprit. It is now
more widely accepted that the blast was likely the result of a stony asteroid that
collided with the Earth's atmosphere. 



Two Upcoming Missions Are Planned To Travel To Asteroids

Tunguska was the largest cosmic impact witnessed by modern humans. It's also
representative of the type of impact we'll have to guard against in the future.
Following the Tunguska incident, astronomers have been paying increased
attention to the likelihood of cataclysmic comet impacts  Today, "Near-Earth Objects."
observation programs are in place to keep an eye out for objects that appear
to be nearing the Earth's atmosphere.  Scientists are currently laying the
groundwork for two separate missions to the asteroids Didymos and Didymos.
The Hera mission of the European Space Agency is scheduled to launch in 2024.
DART is a NASA project that will launch at the end of this year. The DART mission
will collide with Didymos' small moonlet in order to explore how we can nudge
an object in space and modify its course, a task we may have to face in the future
if a dangerous object is heading for Earth. The Hera expedition will travel to
Didymos to study DART's impact.