meteorites

If we look at the global statistics of finds of meteorites on our planet We may think that they are distributed homogeneously throughout the territory, but the reality is very different. Official data indicates that of the approximately 80,000 meteorites cataloged all over the world, more than 50,000 have been found in Antarctica… And this raises a big question: does Antarctica have something special about having so many meteorites? A contradiction. Although we talk about 60% of the meteorites that have been found on Earth come from Antarcticacollision theory tells us another. Specifically, physics, which tells us that meteorites fall randomly and uniformly throughout the planet, so Antarctica does not receive more impacts than the Sahara Desert or the Pacific Ocean. So… Why do we find so many meteorites on the frozen continent? The answer lies in a perfect combination of glaciologyvisual contrast and a natural “trap” that is now, ironically, being sabotaged by climate change. The conveyor belt theory. To understand why Antarctica is the great archive of the solar system, you have to understand how ice moves. And the secret is not in how the rocks fall, but in how the ice delivers them to humanity. To do this, we must go to glaciological models and studies from programs such as ANSMET, where they point out that Antarctica It is a real meteorite conveyor belt. The process. In this way, a meteorite when it falls inside the frozen continent buried deep in the ice sheet. Once here, the natural flow of the glaciers will push the ice that stores the rock inside from the center towards the coast. At certain points, the ice encounters barriers beneath the glaciers, such as hidden mountains that slow its flow and forces the ice to return to the surface. And this is where the famous katabatic winds come into play, which are truly fierce and dry with a force capable of eroding the upper layers of the ice from solid to gas. The result. It is what scientists call the ‘Meteorite Stranding Zone’ (MSZ) or blue ice areas. It is nothing more than the part of ice that has been worn away, but has not affected the rock it stored in any way. That is why over time, meteorites that fell thousands of years ago and traveled trapped in the depths of the ice now appear on the surface as if someone had put them there. A contrast trick. Logically, finding a meteorite among a pile of red ones can be somewhat complicated in our environment. But when we talk about a black rock on a white sheet like ice, the truth is that visually it is easy to find it. That is why this contrast is the best ally that meteorite searchers have. The preservation. But beyond the fact that finding a rock the size of a walnut in the middle of the jungle is a really complicated task, it must be taken into account that humid climates degrade the meteorite quickly. Something that does not happen in Antarctica, which is technically a polar desert. The dry environment it has acts like a real freezer which preserves the samples almost intact for millions of years. This allows scientists to recover not only the rock, but pristine information about the origins of the solar system. And that is why all these factors together make it more common to find more meteorites in this location than in others, and not because there is a predilection for falling here. An invisible threat. As pointed out a study published in Nature, we have a serious problem on the table: We are losing about 5,000 meteorites a year. Intuition would tell us that if the ice melts due to climate change, more rocks would emerge. But the opposite is true due to the thermal properties of the meteorites themselves. Being dark rocks (and many of them metallic with high thermal conductivity), they absorb solar radiation much more efficiently than the surrounding ice. Even at subzero temperatures, the rock heats up enough to melt the ice just below it. This causes the meteorite to sink and create a small pool of water that refreezes them, burying the rock out of sight of researchers or satellites. Thermal models suggest that this disproportionately affects iron meteorites, which are especially valuable for understanding planetary cores, causing us to have many more chondrite or rocky meteorites. Race against time. Humanity has so far managed to recover 23,000 meteorites, giving us a large cosmic library that allows us to better understand everything around us. The problem is that the clock is ticking, and the most important part of the archive is beginning to sink, so now the most important thing is to hurry up to get the most valuable meteorites for us. Images | Kamran Abdullayev henrique setim In Xataka | In 2011, a collector bought a meteorite in Morocco. It has turned out to be direct evidence of thermal water on Mars