Meteorite hunters destroyed billions of years of data

Because of their rarity and origin, meteorite samples are often valuable scientific resources. Some species are even invaluable, as researchers can extract mounds of information about the origins of our universe from them; They are real cosmic archives. Unfortunately, researchers at MIT and Paris City University recently discovered that, in their quest to study them, specialists also inadvertently destroyed much of this valuable data.

To launch nose worms at these rocks from space, researchers can use several angles of attack. In addition to studying its chemical composition and mineral structure, researchers are also interested in other, more secretive but equally revealing clues.

This relates to physical phenomena such as magnetism. In fact, many rocks contain so-called ferromagnetic minerals. During the formation of matter, these metals tend to become magnetized and align with the magnetic field of nearby objects. Once the structure is set, the rock thus retains a trace of the conditions under which it was formed.

Magnetism, Universal Archive

A godsend for researchers, because studying these magnetic remnants can yield a lot of information. It’s even a specialty in its own right: we’re talking paleomagnetism.

It is a group of very important technologies that have played a crucial role in the study of the Earth. Much of what we know about the origin and dynamics of our planet is due to the properties of magnetic minerals. For example, it was this ancient magnetism that provided some of the most convincing evidence for the theory of continental drift leading to modern plate tectonics. This phenomenon was highlighted thanks to the successive inversions of the Earth’s magnetic field, which were recorded in the rock

And this is not just about our good old blue planet. When they form in the core of a magnetic field, other planets and magnetic meteorites can also record information in this way. Every time something in this category reaches Earth, it is thus a veritable science gift package that falls from the sky.

Scientific treasure has become unusable

The problem begins with befriending these magnetic meteorites. There is actually a simple test that consists of placing a suspicious stone near a magnet. If it has magnetic properties when it was found in a geological terrain that it doesn’t, that’s usually a good indication that it’s a meteorite. After that, other magnets are used to perform other tests in the laboratory.

But these checks also have serious consequences. In fact, the presence of magnets, even a weak one, can alter the integrity of the magnetic archives present in the rock. The study authors cite in particular the special representative case of NWA 7034a Martian meteorite found in Morocco in 2011.

It is one of the oldest objects to have traveled to Earth from the Red Planet. In fact, the meteorite formed about 4.4 billion years ago, at the beginning of the solar system’s history. So the researchers hoped to extract heaps of fascinating information about the origins of our cosmic neighborhood.

A small grain of zircon could redefine the search for life on Mars

See more

By looking at the samples, they were actually able to gather some very interesting information (see our article above). But when it came to doing magnetic analysis, they were quickly disappointed. they do not have Not the slightest trace of these famous magnetic archives has ever been found, not even a vulgar snippet of usable information. In other words, billions of years of data went up in smoke during demagnetization. Heartbreaker for planetary scientists.

The potential for frequent damage is very high

This was not the first time this disappointment had been documented. On the other hand, this phenomenon has not been fully studied. A gap Foteini Vervelidou, a planetary scientist at MIT, has sought to fill with her teams.

The researchers began by modeling the effect of the magnetic field of a small neodymium magnet on rocks of various sizes. This allowed them to check the strength of these simulations by exposing pieces of ground basalt to the same magnet. They got consistent results. This means that their model correctly describes how magnets affect rocks.

They then compared these results to those they gathered by analyzing different parts of NWA 7034. Again, everything matched the model exactly. This indicates thatThe identification process itself played an important role in demagnetization NWA 7034 is thus at the loss of this precious data.

And above all, it means that Piles of other potentially promising meteorites could have been inadvertently “sterilized” in this way., simply because the meteorite hunter got so excited about his magnet. This is the first time that the study makes it possible to understand the magnitude of the phenomenon, and we will have to draw the necessary conclusions.

New preventive measures are needed

The good news is that they have also shown that this demagnetization process is not instantaneous. It is progressive, and appears to follow a very precise curve that the researchers have been able to capture on paper. This will allow reference curve for other researchers They know precisely what magnetic field they can expose a piece of meteorite to before destroying the information it contains. This would also make it easier to find usable samples.

However, they wanted to conclude their paper with a caveat. According to the authors, it will be necessary to take this demagnetization into account in the future. This will be more important for the more famous missions. In particular, the researchers mention the transfer of samples from the Mars 2022 mission.

In fact, the Perseverance rover is currently collecting rock samples on the Red Planet. This material will be returned to Earth by 2030 as part of the Mars Sample Return mission (see our article). Researchers hope to find heaps of fascinating elements in the history of Mars and its neighbors. This will particularly include the study of magnetic minerals.

Therefore, the study authors warn that precautions must be taken to protect them. It would be necessary to be very careful not to subject this material to a magnetic field of extreme intensity during and after the flight. Otherwise, there is a risk of destroying some of this priceless information. An unacceptable result, knowing that this article will come close to approx 10 years to go back after being collected 250 million miles from Earth on a multibillion dollar mission…

Study text is available here.