You might think that what I am showing on screen is just a small drainage pond as part
of a farmer's field.
However, this is not the case.
Although it is surrounded by farmland, this pond has a much more interesting origin.
It is in fact a 110 meter wide impact crater known as Kaali Crater.
It formed when a small asteroid fragmented and struck a remote section of Estonia 3500
years ago, thus forming a series of 9 impact craters.
This event was one of the few impact events which not only occurred while humans were
on the planet, but also fell in a populated area.
This video will discuss this fascinating impact crater, and describe the scope of the impact
event.
The Kaali impact craters can be found in the western edge of Estonia.
Specifically, they are located in the center of Saaremaa island near the town of Kaali.
These 9 impact craters originated in approximately 1495 BC, when a small asteroid was on a collision
course with earth.
This asteroid measured 6.3 meters or 20.6 feet wide, and was a dense iron nickel meteorite.
Asteroids of this composition originated more than 4 billion years ago, and represent a
section of a differentiated core from a much larger asteroid.
As this 2,700 ton mass of rock approached the planet, it was further accelerated by
the pull of Earth's gravity.
Entering the upper atmosphere, it was traveling at 15 kilometers per second or 34,000 miles
per hour.
At the time, several thousand people lived in the area, which were considered to be part
of a bronze age culture.
Due to the many legends that seem to reference this event, we know that people witnessed
this asteroid travel across the sky and produce a bright streak of light.
Due to the asteroid's small size, one third of its mass suddenly broke into 8 large fragments,
while the main mass of material continued.
Less than a second later, these fragments struck a densely forested area of Estonia,
generating a series of massive explosions.
Altogether, these explosions produced the equivalent of a 20 kiloton explosion of tnt.
As this explosion occurred, a powerful shockwave was generated which raced outwards.
Due to the extreme wind speeds of this shockwave, all trees in a 530 meter radius of the impact
were flattened.
If a person was to stand 1 kilometer from the blast, they would experience an 85 kilometer
per hour wind.
However, this explosion also created another hazard due to the type of rock it struck.
These fragments struck a thick layer of dolostone, which contains abundant magnesium in its crystal
structure.
Soon, a vast quantity of superheated magnesium gas spread over the landscape, igniting all
vegetation and animals in a 6 kilometer radius, thus incinerating them.
When locals eventually came to see what had just happened, they found a highly active
forest fire.
Due to the vast energy released from this multiple impact event, a loud boom was audible
to all in a 225 kilometer radius.
After the forest fire was extinguished, the consequences of this meteorite impact became
clear.
A series of 9 impact craters had been constructed over an area of half a square kilometer.
The main crater measured 110 meters wide and 22 meters deep.
As for the smaller craters, they measured between 13 and 39 meters wide and 1 to 4 meters
deep.
Although the vast majority of the impacting meteorite was vaporized, small fragments of
material, weighing up to 30 grams have been found in the landscape.
These iron meteorites, when cut open, display a silvery pattern of crystals known as a Widmanstatten
pattern.
Due to the abundance of ash released by the impacts, a thick layer of material fell within
the main crater.
These fine particles created an area for rainwater to pool, and as a result this crater is now
the site of a small pond.
I hope that you enjoyed this video!
If you would like to request a specific topic, please leave a comment below.
Additionally, if you wish to support this channel consider becoming a patron on patreon!