In 2011, nomads roaming the western Sahara encountered valuable time capsules from Mars: coal-black chunks of a meteorite, strewn across the dunes. “Black Beauty,” as the parent physique came to be identified, captivated scientists and collectors simply because it contained crystals that formed on Mars much more than four.four billion years ago, creating it older than any native rock on Earth. Jérôme Gattacceca, a paleo-
magnetist at the European Centre for Study and Teaching in Environmental Geosciences, hoped it could harbor a secret message, imprinted by the now-defunct martian magnetic field—which is believed to have helped the planet sustain an atmosphere, water, and possibly even life.

But when Gattacceca obtained a piece of Black Beauty and attempted to decode its magnetic inscription, he discovered its memory had been wiped—Males in Black style—and replaced by a stronger signal. He instantaneously knew the culprit. Someplace along its journey from Moroccan desert to street dealers to laboratory, the rock had been touched by sturdy hand magnets, a broadly utilized strategy for identifying meteorites. “It’s a pity that, just by making use of magnets, we’ve been destroying this scientific details that was stored there for four billion years,” Gattacceca says.

In a new study, Foteini Vervelidou, a planetary scientist at the Massachusetts Institute of Technologies (MIT), and her colleagues have documented the destructive energy of the hand magnets, which are typically produced from uncommon-earth metals such as neodymium and are commonly about ten,000 instances stronger than Earth’s magnetic field. When brought inside a couple of centimeters of a rock, the researchers discovered, the magnets overwrite vestigial fields contained in iron-primarily based minerals such as magnetite and reset them to the larger strength and orientation of the magnet. In an immediate, a special view into the heart of distant rocky bodies can be erased. Black Beauty, for instance, is the only identified meteorite old sufficient to “remember” Mars’s magnetic field prior to it began to disappear about four billion years ago.

Vervelidou hopes that raising awareness will enable convince hunters, collectors, and researchers to give up a strategy that is nevertheless promoted by the U.S. Geological Survey, universities, and well known meteorite hunting Television shows. “It’s like possessing this special piece [of information] destroyed,” Vervelidou says. “Why would you invest in an remarkable painting and then throw some sauce on it?”

Hand magnets are efficient for distinguishing ordinary chondrites, an abundant type of meteorite that is typically loaded with metals, from quite a few Earth rocks. But their diagnostic skills have limits. Some frequent iron-wealthy Earth rocks, such as basalt, can also attract magnets, whereas the meteorites that come from Mars or the Moon typically do not. Most of the iron on these bigger bodies is in their core, not their crust, exactly where meteorites originate. “The irony is that the [meteorites] that do not stick to magnets are essentially the most worthwhile of all,” says Ben Weiss, a study co-author and MIT planetary scientist.

The issue is not new. Two decades ago, Weiss was studying uncommon meteorite samples to see no matter whether some asteroids have been ever major sufficient to have a dynamo—a churning molten core that generates magnetic fields. He saw spectacularly higher magnetizations in every of the samples only to understand, later, that he’d been duped by magnets. Weiss says the meteoritic literature is rife with false magnetic findings—such as reports of intense fields in a single of the most studied meteorites of all time, Allende, which fell in Mexico in 1969. “I wasn’t the initial a single to be fooled.”

Immediately after the aggravation of locating magnetic contamination in nine distinct Black Beauty samples, the researchers decided to confront the hand-magnet concern head-on. In their study, accepted this week by the Journal of Geophysical Study: Planets, they calculated how magnets of distinct strengths would alter a meteorite’s magnetic records as they approached the rock. Study co-author France Lagroix, at the Paris Institute of Planetary Physics, helped verify the calculations by measuring the fields in 13 specimens of terrestrial basalt prior to and right after putting a common hand magnet at several distances from them. The benefits showed how the magnet progressively resets fields from the outdoors in, providing researchers a guide for how deep they would have to reduce to obtain a pristine sample. “Now we’re one hundred% positive, if we weren’t currently, that this is what’s going on,” Weiss says.

Black Beauty, a meteorite from Mars,
The magnetic memory of Black Beauty, a meteorite from Mars, was destroyed by magnets.NASA

But for most people—even other meteorite researchers—the magnetic records are not as valuable as they are to paleomagnetists. The “quick-and-dirty” process of meteorite identification persists simply because “not everyone cares about magnetic fields like Ben Weiss does,” says Carl Agee, the meteoriticist at the University of New Mexico who initial determined Black Beauty hailed from Mars.

For the previous two decades, Hasnaa Chennaoui Aoudjehane, a planetary scientist at the Hassan II University of Casablanca, has been attempting to educate Saharan meteorite hunters about the dangers of hand magnets. But the message does not normally sink in. “We attempt explaining to hunters … ‘it’s the human heritage it is the history of the Solar Program,” Chennaoui Aoudjehane says. “But when a person wants to invest in bread and factors to reside each and every day … their priority is not the science that is carried out on these rocks. It is their supply of income.” Saïd Yousfi, a meteorite collector and dealer in Morocco, agrees magnets will stay a fixture of the Saharan meteorite-hunting culture—despite the truth that most nearby hunters are skilled sufficient to determine meteorites by eye.

In their study, Vervelidou and her colleagues advise an option: susceptibility meters. These devices apply a weak magnetic field that does not erase the records, and they are improved at identifying distinct sorts of meteorites. The catch is that industrial devices typically expense a couple of thousand dollars, and they’re not as intuitive to use as a easy magnet. Gattacceca and colleagues are now creating handheld susceptibility meters that have only a single button and expense a couple of hundred dollars.

Gattacceca hopes to make inroads with scientists. He points to the Antarctic Search for Meteorites (ANSMET), an annual expedition funded by the National Science Foundation. His collaborators there told him they weren’t making use of magnets on their samples, so he assumed the massive magnetizations he was locating have been relics of the early Solar Program.

But a couple of years ago, a colleague participating in the expedition brought back a tiny hand magnet adorned with the ANSMET logo. It had been distributed in the researchers’ field kits. “That’s what you contact a smoking gun,” Gattacceca says. “Once you have the gun, you are probably to use it.” 

By Editor

Leave a Reply