What you are looking at is a large 24 kilometer wide circular feature within Germany.
For a long time, this feature was considered to be the remnants of a massive caldera collapse,
much like a larger variant of the ice age Laacher See volcano within the country which
erupted 13,000 years ago.
However, in 1960 a very famous scientist known as Eugene Shoemaker proved otherwise due to
some unusual evidence.
Among other pieces of evidence, he found that one of the medieval churches was built almost
completely of a rare rock type known as suevite.
Suevite is a type of breccia only formed from large asteroid impacts.
Thus, this massive circular depression was not a caldera but rather an impact crater.
However, this crater is even more interesting.
A rare green gemstone which is found to the east known as moldavite has since been proven
to have originated from this impact crater.
This video will discuss when this crater formed, the scope of the impact, and how moldavite
formed.
The Nördlinger Ries crater can be found in south central Germany to the north of Munich.
Another major nearby city is Nuremburg, which is located 73 kilometers to the northeast.
To the southwest of this crater is another large impact crater called Steinheim Crater.
Until recently, these two craters with a near identical age were thought to have originated
from a large asteroid which was accompanied by a small moon which impacted the surface.
However, more recent evidence has shown that Steinheim is in fact 500,000 years younger
than Nördlinger Ries.
The Nördlinger Ries impact crater formed 14,808,000 years ago, when an asteroid measuring
1.6 kilometers or 1 mile wide was on a collision course with Earth.
This mass of rock was an unusual variety of asteroid known as an achondrite.
Although it was a stony asteroid much like a typical chondrite, it did not contain the
rounded grains of material known as chondrules.
This asteroid had a similar composition to the known asteroid 3103 Eger, suggesting that
they had a similar origin.
As this large asteroid entered the Earth's atmosphere, it was travelling at 19.4 kilometers
per second or 43,000 miles per hour.
A bright streak of light soon became visible as the asteroid continued its descent.
A few seconds later, it impacted the surface at an angle of 40 degrees generating a massive
explosion equivalent in energy to the detonation of 324,000 megatons of tnt.
As a large fireball was created on impact, a magnitude 8.3 earthquake was generated.
Simultaneously, due to the immense heat and thermal radiation generated by the impact,
any lifeforms in a 360 kilometer radius immediately ignited.
This meant that any creatures in the southern two thirds of Germany, and parts of Austria,
Switzerland, Luxembourg, Belgium, France, Italy, Slovenia, and Czech Republic experienced
massive fires.
As a powerful shockwave expanded outwards from its center, any trees and other vegetation
in a 410 kilometer radius were flattened.
Due to the angle the asteroid struck at, large fragments of material were ejected high into
the atmosphere.
Due to the temperatures these ejected fragments experienced, they turned into a variety of
glass known as tektites.
These fragments would later rain down on the planet up to 500 kilometers away to the east,
depositing an unusual variety of green glass known as moldavite.
After the dust and fires from the event cleared, the newly formed impact crater became visible.
This new crater measured 24 kilometers wide and 950 meters deep.
Although it has not yet been definitely proven or disproven, there is a decent possibility
that this impact caused a wave of extinctions around the planet.
Just after this impact occurred, a small magnitude mass extinction event called the Middle Miocene
disruption occurred.
Regardless of its cause, the extinction event was hardest hitting for a series of large
reptiles which included various crocodile and turtle species.
Although much of Nördlinger Ries has since been filled in by erosion, the overall edifice
is still approximately 150 meters lower than the surrounding landscape.
I hope that you enjoyed this video!
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