On Earth, the atmosphere slows small
meteorites so much that they merely pit the ground. Only meteorites
that are house-sized or bigger blast out a crater many times
larger than the meteorite itself. From the size and structure
of a crater, we get some indication of the size and speed
of the body that formed it. A giant impact yields an enormous
crater with central peaks or multiple rings. A smaller one
leaves a simple, bowl-shaped crater.
Location: Eastern Siberia
Size/Shape: Small impact
that left pits up to 28 m (92 ft) across.
Age: Fall observed in
Meteorites: 23 metric
tons (50,000 lbs) of iron meteorite fragments were recovered.
Crater: Wolf Creek
Size/Shape: Simple crater
nearly a kilometer (.56 mi) across. Rim 25 m (80 ft) high.
Age: Less than 300,000
Meteorites: Iron meteorite
fragments still found in vicinity.
Crater: Mistastin Lake
Size/Shape: 28 km (17
mi) across with a central peak. Glaciers have eroded much
of the original structure.
Age: 38 million years
Meteorites: No meteorite
Location: Quebec, Canada
(60-mi), multi-ringed structure. The ring-shaped lake encloses
a central uplift.