Does he keep it a secret? Scientists have recently identified the origin of a Martian meteorite, which they consider to be an “open book” in the early moments of Mars. The object of the red planet is potentially rich in the text of the formation of the earth.
NWA 7034, nicknamed “Black Beauty”, has fascinated geologists since its discovery in the Sahara in 2011.
The “oldest” Mars rock
The block, which is easy to hold and weighs just over 300 grams before being cut, is “our oldest rock, not only on Mars but almost on Earth,” explained astronomer Sylvain Boley, who co-signed the study. In Tuesday Communication with nature On this subject.
It contains zircon, a type of mineral that is 4.46 billion years old. Or the solar system “about 80 million years after the beginning of the formation of the planets”, said Sylvain Boley, a professor at the Geosciences Laboratory at the University of Paris-Sacle.
The NWA 7034 is thus an “open book of the first moments of Mars”, when its magma surface begins to harden. Although we have “lost this primitive history of our planet”, where most of the mainland has disappeared, in the great reconstruction of plate tectonics – an event that has largely saved Mars.
A hole in the southern hemisphere of Mars
The team of researchers, led by astronomers from Curtin University in Perth, Australia, with the strong contribution of French institutions, has succeeded in determining the exact source of meteorites in a region hosting a very primitive crust from the Red Planet.
He had to identify a hole, which was formed by the effect of a meteor coming from space “enough energy to escape the gravity of Mars, at a very high speed, enough to pull the rock out at a speed of more than 5 km / s”. Scientist and first author of research at Curtin University. The diameter of such holes should be at least 3 km. The problem is, Mars has at least about 80,000 of this size.
The second source, the researchers knew that NWA 7034 was released into space about five million years ago, thanks to the measurement of cosmic ray exposure. “So we were looking for a very young and large hole,” said Anthony Lagine, AFP, whose doctoral thesis focused specifically on dating Mars holes.
Another source, an analysis of the composition of “Black Beauty” shows that it was brutally heated 1.5 billion years ago, probably under the influence of an asteroid. In other words, the rock was pulled out of the first surface before it fell further, where another impact this time threw it into space, all the way to Earth.
Equipped with this information, Anthony Lagain developed a crater detection algorithm built into the cartin. A mosaic of 90 million photos of holes in Mars before it was crushed with a super computer, thanks to a NASA satellite camera.
The result is that the choice shrinks to 19 pits and then to one, Karratha. The 10-kilometer-diameter hole is “located in a very old region of the Southern Hemisphere, rich in potassium and thorium like Black Beauty,” says Anthony Lagain. The final argument is that the only meteor on Mars is very magnetic, but “the region where Carratha is located is the most magnetic on Mars.”
“Understand what happened in the beginning”
The region, which stretches across the Terra Simeria and the region of Sirenum, is “probably a ruin of the oldest crust on Mars,” according to the study. Who applied to send a mission dedicated to the study of its geology.
Professor Boli points to a kind of “bias” that focused Mars missions on the search for signs of water and life, at the expense of earlier times, which allowed their appearance. Moreover, after its discovery, NWA 7034 took its first place due to the presence of water in it.
However, to understand the structure of the first planet’s crust one must understand what happened at the very beginning, recalls Anthony Lagine and “how we got to an exceptional planet like Earth in the universe”.