Notorious meteorite, which helped to cleanse the Land of the dinosaurs, in fact, could be double, that is, in the planet crashed two asteroids that were in orbit each other.

Usually it is considered that the diameter of the killer giant lizards ranged from 7 to 10 km, but this may be the overall diameter of the system of two up In the basis of a new hypothesis - revaluation of share of craters formed in the result of the double impact.

Among the scars that are left on the Earth from the dual shock, first of all it should be called Clearwater in Quebec (Canada) near Hudson Bay, formed about 290 million years ago. Such examples are rare: only one crater has a couple of fifty.

And this is strange: it is estimated double asteroids floating in the vicinity of the Earth, they must be much more. "Fifteen years old it is known that approximately 15% of near-earth asteroids are binary," says Katharine milkovich from the Paris Institute of physics of the Earth (France). With other conditions being equal to 15% of terrestrial impact craters were formed because of the double strike. Why, in reality, they are much less?

Ms. milkovich and her colleagues offer the following explanation. Computer modeling showed that binary asteroids often constitute one crater.

And this is not unusual because the crater may be ten times the asteroid. In contrast, the researchers found that only in exceptional cases, a couple of small and very distant from each of the objects is guaranteed to form a pair of craters. That's why on Earth there is only 2%.

This is a clear hint that binary asteroids fall to the Ground more often than we thought, trusting the craters.

Modeling also allows building of the assumptions on which the craters have a double origin. First, they must be asymmetric, and then one of the candidates is the Chicxulub crater in Mexico, which, according to some, 65.5 million years ago was a result of the strike, resulting in the death of the dinosaurs.

Peter Pravets of the Academy of Sciences of the Czech Republic indicates that clarify the history of craters, especially buried under earth and water, allows the study of gravitational anomalies created exceptionally strong impacts. According to the specialist, the recent gravimetric survey of the surroundings of Chicxulub confirms the conjecture of Ms. milkovich.

Calculations of the French group suggests that, since the diameter of this asymmetric crater is about 180 km, the Earth was faced with two objects with a total diameter of 7-10 km - the same figure who is used to attribute a single meteorite. The asteroids were divided about 80 km. of Course, all this is very approximate figures.

Jean-Luc Margot at the University of California in Los Angeles (US) notes that suspicions about the belonging of some single craters double asteroids have been kicked around for a long time, but only now it moved a little more than talk.

The study is published in the journal Earth and Planetary Science Letters.

Prepared according to NewScientist.