(ORDO NEWS) — Depending on the type of soil in the area of the explosion, its strength could range from 0.5 to 13 million megatons. The resulting huge crater was named by astronomers after the famous science fiction master Frederick Pohl.
According to modern concepts, the northern hemisphere of the Red Planet was once covered by an ocean that occupied a third of its surface. Today this zone, the former seabed, lies four to five kilometers below the surrounding plains.
Nearby there are traces of a serious wave action, similar to the traces of a powerful tsunami, but it looks too strong for an event of volcanic origin – just like the traces of a planetary tsunami present in the earth’s layers 66 million years old.
Numerous traces of an ancient and especially strong tsunami on Mars 3.4 billion years ago have long attracted the attention of scientists.
Due to the large scale, it was logical to assume that it was caused by the fall of a large asteroid. But it remained unclear exactly where he fell.
And without the discovery of a crater, it is impossible to assess the strength of the explosion that gave rise to it.
The researchers conducted a thorough analysis of images of the surface of the fourth planet and found a crater with a diameter of about 110 kilometers on the Chrys Plain.
They named it after the famous science fiction writer Frederik Pohl (1919-2013).
During the existence of the ancient Martian ocean, this area was about 120 meters below sea level – that is, in the usual language, part of the continental shelf.
It is in such a place that it is easiest for an asteroid explosion to generate powerful, far divergent waves.
A similar thing happened on Earth 66 million years ago, when a large asteroid fell off the coast of modern Mexico, also on the shelf.
According to calculations based on the parameters of the found crater, it could have been generated by an explosion of at least half a million megatons with a power – this is ten thousand times more powerful than the Tsar Bomba explosion, the largest ever produced by people.
Moreover, its power was such if the asteroid hit soft rocks. If the rocks at the point of impact were denser, the explosion power could be much higher – up to 13 million megatons, or about a quarter of a million Tsar bombs.
According to the conservative low-power explosion scenario, the height of the tsunami wave that hit the coastal regions of Mars at this point should have reached 250 meters. The waves then entered areas that were one and a half thousand kilometers away from the sea coast.
The researchers compare this event to the megatsunami after the fall of the Chicxulub asteroid 66 million years ago. Then, as it is believed, the blow fell on the seabed, 200 meters below the surface of the ocean.
The diameter of the crater immediately after the explosion was more than 100 kilometers, and the height of the megatsunami reached 200 meters.
True, waves with such a height hit only the Americas, Africa then reached a wave with a height of only about eight meters.
The power of the explosion 66 million years ago was higher than the one that formed the Pola crater. However, the impact occurred on a deeper layer of water and a different seabed geology, so the tsunami was smaller here.
This impact was far from the most powerful in the history of the Red Planet. In its southern hemisphere there is the so-called Hellas Plain with a diameter of 2300 kilometers, whose bottom is nine kilometers lower than the surrounding area.
In addition to this very large impact crater (there is nothing like it on other bodies in the solar system), Mars has even more impressive impact marks.
For example, a number of researchers believe that its northern polar basin was formed as a result of the fall of a body with a diameter of 1900 kilometers.
It occupies 40% of the planet, that is, about fifty million square kilometers. If his impact status can be confirmed, he will become the undisputed champion of the solar system among traces of asteroid impacts.
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