Scientists are trying to confirm that a black rock discovered in Morocco in 2018 left Earth, travelled into space and returned like a prodigal son.

This meteorite left Earth. It came back thousands of years later.

 

Isn't this the "THE KING IS BACK" show?

If true, this rock, officially named 'Northwest Africa (NWA) 13188', would be the first meteorite (that we know of) to make this remarkable round trip.

Weighing 646 grams, this 'boomerang space rock' is not the only strange thing about it.

The bubbly appearance, crystalline texture, and delicate chemical structure of NWA 13188 strongly point to rock types composed of molten minerals produced by volcanoes near sinking oceanic plates on Earth.

When we add the mixture of oxygen isotopes and the signature of trace elements, it becomes highly suspicious that this rock is a meteorite. At least not a typical space rock.

Nevertheless, according to geophysicist Jérôme Gattacceca of the French National Centre for Scientific Research, who presented his team's findings at the Goldschmidt geochemistry conference in France, this rock had an interesting journey, spending a significant amount of time in orbit.

The concentrations of Helium-3, Beryllium-10 and Neon-21 can only be explained by exposure to cosmic rays (radiation that exists in space but is largely blocked by Earth's magnetic field).

Although the concentration of these isotopes was lower than in other meteorites, it was significantly higher than in other rocks on Earth.

This suggests that NWA 13188 was exposed to galactic cosmic rays for a short but significant period of tens of thousands of years.

NWA 13188 also has a glassy 'fusion crust', suggesting that it may have melted during a fiery entry into Earth's atmosphere.

All of this "precludes NWA 13188 from being a man-made 'fake' meteorite," Gattacceca and colleagues write.

"Therefore, we consider that NWA 13188 is a meteorite that was ejected from Earth and then fell back to the Earth's surface," they conclude.

Researchers say it is a mystery how this Earth rock travelled into space, but it could have been ejected during a volcanic eruption or hurled into space when another meteor hit the Earth.

A rock hurled from the mouth of a raging volcano would have to be moving at tens of thousands of kilometres per hour to enter orbit, much faster than most rocks can fly.

The highest volcano eruptions usually reach heights of only 31-45 kilometres (101,700-147,600 feet) above the Earth, so it is unlikely that volcanoes could eject rocks into space.

Some collisions between Earth and large asteroids can be powerful enough to hurl rocks into the Solar System.

The oldest rock known to science, a 4 billion-year-old Earth rock, was found on the Moon during the Apollo 14 mission in 1971. This rock was probably ejected from Earth to the Moon, which was much closer at the time, following an asteroid collision.

The age of NWA 13188 is unknown, but Gattacceca's team is trying to date the rock by measuring concentrations of an argon isotope.

The research, which has not yet been published, has not convinced everyone. "If you put forward extraordinary hypotheses, you need extraordinary evidence to support them. I'm still not convinced," planetary scientist Philippe Claeys told Alex Wilkins of New Scientist.

Meteorites from Mars have also been found in the Sahara desert; a 4.4 billion-year-old stone called 'Black Beauty' was discovered by local meteorite hunters and sold to a private collection in 2011. It currently has a market value of more than 10,000 US dollars per gram.

The Sahara Desert is an ideal place to look for meteorites because the black stones stand out against the sand and there is little vegetation to block the view.

As many as 780,000 meteorites may be hiding in the Sahara, making it the best meteorite hunting location outside Antarctica.

 

Source: https://www.sciencealert.com/