Kaali
Europe's best known meteorite crater, struck while people lived nearby.
Key facts
- When
- about 3,500 years ago (some studies suggest it may be older)
- Where
- Saaremaa island, Estonia
- What hit
- an iron meteoroid of perhaps 20 to 80 tonnes, which broke up in the air
- Era
- In the age of humans
- Location
- 58.37° N, 22.67° E
The main crater probably took a few kilotons of TNT; estimates range up to about the Hiroshima bomb.
Comparable to a small nuclear weapon, on an island where people were living.
What happened
On the Estonian island of Saaremaa a round lake about 110 m across sits in a crater with steep, wooded banks. Eight smaller craters lie nearby. They were made by fragments of an iron meteorite that broke apart as it came down.
The impact happened in the Bronze Age, when farming people lived on Saaremaa. The craters were confirmed as meteoritic in the 20th century, after small fragments of iron were found in and around them.
The main lake later became a place of significance: excavations have found the remains of a stone wall around it and many animal bones, suggesting offerings were made there.
Effects
The blast would have flattened forest for kilometres around and set fires. Some researchers have suggested the event could be remembered in Baltic and Finnish folklore, but this cannot be proved.
The evidence
Small pieces of iron meteorite, melted iron droplets in the soil, overturned rock layers and the crater field's layout.
Did you know?
The main Kaali crater is a protected natural monument.
Dating the craters has been difficult; charcoal, peat and impact debris give different estimates.
Related pages
How is impact energy measured? See energy explained, or try the impact calculator.