Moon may harbour alien minerals, study says

May 26, 2013
View of a full moon in Panama City on April 25, 2013. Minerals found in craters on the Moon may be remnants of asteroids that slammed into it and not, as long believed, the satellite's innards exposed by such impacts, a study said Sunday.

Minerals found in craters on the Moon may be remnants of asteroids that slammed into it and not, as long believed, the satellite's innards exposed by such impacts, a study said Sunday.

The findings, published in the journal Nature Geoscience, cast doubt on the little we knew of what the is actually composed of.

It had long been thought that meteoroids vaporise on impact with large .

Unusual minerals like spinel and olivine found in many lunar craters, but rarely on the Moon's surface, were therefore attributed to the excavation of sub-surface lunar layers by asteroid hits.

Olivine and spinel are common components of asteroids and meteorites, and have been found on the floors and around the central peaks of like Copernicus, Theophilus and Tycho that are around 100 kilometres (63 miles) in diameter.

A team from China and the United States simulated the formation of Moon craters and found that at impact velocities under 12 kilometres per second a projectile may survive the impact, though fragmented and deformed.

"We conclude that some unusual minerals observed in the central peaks of many lunar could be exogenic (external) in origin and may not be indigenous to the Moon," they wrote.

Co-author Jay Melosh from Purdue University in Indiana, said the finding answers the conundrum exposed by earlier studies which said craters the size of Copernicus were not big enough to have dredged up the contents of the Moon's deep, interior mantle.

"It also warns planetary scientists not to use the composition of the central peaks of craters as a guide to the interior of the Moon, whose dominant mineral might not be olivine," he told AFP.

On Earth, spinel and olivine create rare gemstones like peridot.

In an article commenting on the study, Erik Asphaug of the School of Earth and Space Exploration at Arizona State University, said the theory meant that material excavated from Earth by large impacts during the planet's early days may still be found on the Moon.

The scattered material was known to have hit the Moon at velocities as slow as 2 km/s and should have survived, if the study's assumptions are correct.

This suggested yet another explanation for the existence of spinels on the Moon, said Asphaug: They came from Earth.

"Even more provocative is the suggestion that we might someday find Earth's protobiological materials, no longer available on our geologically active and repeatedly recycled planet, in dry storage up in the lunar 'attic'.

"Certainly, the potential of finding early Earth material is emerging as one of the primary motivations for a return to the Moon by human astronauts in our ongoing search for the origin of life."

Unlike the Earth's crust, which is repeatedly recycled through the process of plate tectonics, the Moon's hard crust dates back billions of years, offering clues to the formation of the solar system, including Earth.

Explore further: Mars, Saturn and the claws of Scorpius

More information: Paper: dx.doi.org/10.1038/ngeo1828

add to favorites email to friend print save as pdf

Related Stories

What craters on the Moon teach us about Earth

Jan 10, 2013

Some questions about our own planet are best answered by looking someplace else entirely… in the case of impact craters and when, how and how often they were formed, that someplace can be found shining ...

Scientists find Moon, asteroids share history

Mar 25, 2013

(Phys.org) —NASA and international researchers have discovered that Earth's moon has more in common than previously thought with large asteroids roaming our solar system.

The origin of the moon's craters

Mar 19, 2012

(PhysOrg.com) -- Moon's craters, together with samples of the surface returned during the Apollo program, tell the story of impacts from two different populations of small bodies. The first rocky collection ...

Recommended for you

Mars, Saturn and the claws of Scorpius

1 hour ago

Look up at the night sky this week and you'll find Mars and Saturn together in the west. Mars stands out with its reddish colouring and you might just be able to detect a faint yellow tinge to Saturn. ...

Electric sparks may alter evolution of lunar soil

4 hours ago

The moon appears to be a tranquil place, but modeling done by University of New Hampshire and NASA scientists suggests that, over the eons, periodic storms of solar energetic particles may have significantly ...

User comments : 0