Editing Río Cuarto craters (section)

== Impact origin theory ==
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The depressions were thought to be due to a grazing impact of a set of objects at a very low angle, which calculations show to be a rare occurrence. Most impacts will strike at an angle of 45 degrees to the horizontal or greater, and the impact craters will always be close to circular, since the shock wave that results from the impact propagates symmetrically.

A grazing impact, however, will form an [[ellipse|elliptical]] crater, with sprays of debris that look like butterfly wings. This has been confirmed by high-velocity guns used for impact experiments, and more recently by computer simulations. On impact, the object may shed chunks of itself that fly further downrange to perform secondary impacts.

Based upon physical and numerical modeling, proponents of the Río Cuarto event suggest that the object struck at an angle of no more than 15 degrees from the horizontal, with the impact itself having 10 times more explosive energy than the [[Barringer Crater]] event and 30 times more than the [[Tunguska event]].<ref name="Planetary and Space Science Centre" /> Although the age of the depressions has not yet been determined precisely, it is believed by some researchers{{Who|date=September 2017}} they are about 10,000 years old, placing them at the start of the [[Holocene]], though the EID gives a broader age of less than 100,000 years old.<ref name="Planetary and Space Science Centre" />