Feeds

Veiny green 'scum' meteorite may be first visitor from Mercury

Four billion year-old Moroccan mystery explained

The smart choice: opportunity from uncertainty

A mysterious green meteorite with a unique geological signature may have arrived on Earth thanks to an explosion on the surface of the Solar System's smallest planet, Mercury*.

The meteorite, dubbed NWA 7325, is actually a 345g package of 35 extraterrestrial stones formed around 4.56 billion years ago that were found in the southern deserts of Morocco last year. According to a paper presented at the 44th annual Lunar and Planetary Science Conference in Texas by meteorite scientist Anthony Irving, the sample looks to be our first recorded visitor from the Sun's closest planetary neighbor.

"It might be a sample from Mercury, or it might be a sample from a body smaller than Mercury but [which] is like Mercury," Irving said, Space.com reports.

The sample, with a "chartreuse-colored fusion crust," has the lowest magnetic intensity of any meteorite yet found, which is consistent from data sent back by NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) orbiter, Irving said, and is very low in iron, an element Mercury looks to be lacking.

Transfer of material from one planet to another is surprisingly common, and samples of rocks from Mars and the almost-planet Vesta have been identified in meteorite specimens by looking at the chemical composition of the rock and matching it – as far as possible – to its source. Using similar methods, NWA 7325 looks to be a Mercurian candidate.

Mercury meteorite

First rock from the Sun?

The escape velocity (the speed needed to get out of a planet's gravity well) of Mercury is 4.3 km/s, less than that of Mars, and Irving postulates that the meteor formed as "scum" on top of a magma field and was ejected by either a volcanic explosion or impact from another body.

But all this is going to remain in the realms of hypothesis until we get more data back from Mercury, Irving explained. The Messenger probe, our first to the planet, has now completed its primary mission of mapping the planet's surface, and NASA is trying to get funding to keep the program running.

"We now have a healthy spacecraft in orbit around a planet that will not be visited by spacecraft again for more than 10 years," said principal investigator Sean Solomon of Columbia University's Lamont-Doherty Earth Observatory last month.

"Our scientific plans for a second extended mission build on past discoveries, can be accomplished with planned orbital observations, span an unprecedented phase of the solar cycle, and include extraordinarily low-altitude campaigns that will offer spectacular new views of Mercury's surface and near-surface environment. We hope that NASA will support the continued investigation of the most enigmatic of the inner planets."

The Messenger probe has sent back some remarkable data, including the existence of numerous volcanoes on the rocky crust, the discovery of ice in polar craters that close to the Sun, and a very sweet but mathematically-probable smiley face on the planet's surface. It'll be at least a decade before another mission is sent to Mercury, assuming funds can be found.

Nevertheless the probe's potential remains, and if Washington could get its funding sorted out we might find out if NWA 7325 is a valid sample or just an offshoot of another galactic flash in the pan. ®

* Bootnote

Sorry, Pluto fans – you lost your "smallest planet" bragging rights in August 2006.

The Power of One Infographic

More from The Register

next story
World Solar Challenge contender claims new speed record
One charge sees Sunswift travel 500kms at over 100 km/h
SMELL YOU LATER, LOSERS – Dumbo tells rats, dogs... humans
Junk in the trunk? That's what people have
The Sun took a day off last week and made NO sunspots
Someone needs to get that lazy star cooking again before things get cold around here
Boffins discuss AI space program at hush-hush IARPA confab
IBM, MIT, plenty of others invited to fill Uncle Sam's spy toolchest, but where's Google?
Bad back? Show some spine and stop popping paracetamol
Study finds common pain-killer doesn't reduce pain or shorten recovery
Forty-five years ago: FOOTPRINTS FOUND ON MOON
NASA won't be back any time soon, sadly
Jurassic squawk: Dinos were Earth's early FEATHERED friends
Boffins research: Ancient dinos may all have had 'potential' fluff
prev story

Whitepapers

Top three mobile application threats
Prevent sensitive data leakage over insecure channels or stolen mobile devices.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Build a business case: developing custom apps
Learn how to maximize the value of custom applications by accelerating and simplifying their development.