Rock launched from Earth likely ‘boomeranged’ back as meteorite, suspect researchers

Reddish-brown stone may have been ejected into space about 10,000 years ago in first such case discovered

A strange dark stone found recently in a remote section of the Sahara desert could be the first ever known case of a rock launched from the Earth that returned to the planet as a meteorite thousands of years later.

The reddish-brown dark stone, found in Morocco in 2018, may have been ejected into space about 10,000 years ago following an asteroid collision with Earth, and remained in orbit before crashing back onto the planet, suspect scientists, including Jerome Gattacceca from CNRS in France.

Researchers found the rock had a glossy coat called a “fusion crust” typically formed as the surface of space rocks entering the Earth’s atmosphere at high speeds begin to melt.

“The presence of a well-developed fusion crust strongly suggests that NWA 13188 is indeed a meteorite,” scientists said.

Traces of alternative forms of elements like Beryllium, Helium and Neon, were also identified on the rock in strangely low concentrations.

“This concentration is very low for a meteorite which would imply an extremely short transfer time to the Earth, on the order of a few kilo years,” researchers said.

This discovery prompted the scientists to conclude that the rock was exposed to a “very short”, but “significant” exposure to cosmic rays for about 10,000 years.

While this initial finding confirmed that the rock is indeed a meteorite, it remained unclear whether it truly originated from Earth.

In a yet-to-be peer-reviewed research on the rock, presented at an international geochemistry conference last week, scientists said it contains some chemical features similar to volcanic igneous rocks on Earth.

“Therefore, we consider NWA 13188 to be a meteorite, launched from the Earth and later re-accreted to its surface,” they said.

It, however, remains unclear how the rock may have been launched from Earth to space in the first place.

“The launch process – impact or direct ejection during a volcanic eruption – remains to be determined,” scientists said.

In further tests, researchers hoped to assess whether the rock contains the element argon captured from the Earth’s atmosphere.

Such trapped argon, they said, “should be particularly abundant” for a rock erupted from Earth.