It is one of the biggest impact craters on Earth - and until now, scientists have been unsure how it got there. The Sudbury Basin in Ontario, Canada, is 39 miles long and 19 miles wide - and 9.3  miles deep. Researchers have been unsure how it formed - but now say it was a giant comet, not a meteorite as previously thought. They say it was caused caused by a comet colliding with our planet over 1.8 billion years ago. The Sudbury Basin in Ontario, Canada, is 39 miles long and 19 miles wide - and 9.3 miles deep. It was formed by a comet hitting Earth 1.8 billion years ago, researchers have found.
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Ontario crater is 39 miles long and 19 miles wide, and 9.3 miles deep
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Was caused caused by a comet colliding with Earth 1.8 billion years ago
Due to the high mineral content of its soil, the floor of the basin is among the best agricultural land in @placeholder.