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How often do impacts occur?
How often an impact occur depends on the site of the NEO. Larger impacts occur much less frequently than small ones.
About a hundred fist-sized meteorites fall every day.
About five 10 metre diameter NEOs explode in the upper atmosphere each year but have no affect on the ground.
A 60 m diameter NEO will hit the Earth every few hundred years and may explode at low altitude to cause local damage.
A 1 km diameter crater will form on the Earth's surface every few thousand years
A NEO larger than 1 km will collide with the Earth every few hundred thousand years and will have global consequences.
A NEO around 6 km that could cause a mass extinction will collide with the Earth every hundred million years.
More information on the frequency of impacts can be seen in our virtual exhibition.
Related Answers
What evidence is there that the Earth has been struck by NEOs?
Is an asteroid or comet on a collision course with the Earth?
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