Researchers have discovered never-before-seen types of crystals hidden in tiny specks of perfectly preserved meteorite dust. The dust was left behind by a huge space rock that exploded over Chelyabinsk, Russia nine years ago.
On February 15, 2013, an asteroid measuring 59 feet (18 meters) in diameter and weighing 12,125 tons (11,000 metric tons) entered Earth’s atmosphere at approximately 41,600 mph (66,950 km/h). Fortunately, the meteor exploded about 23.3 kilometers above the city of Chelyabinsk in southern Russia, flooding the surrounding region with tiny meteorites and avoiding a single colossal collision with the surface. Experts at the time described the event as a major wake-up call about the dangers asteroids pose to the planet.
The Chelyabinsk meteor explosion was the largest of its kind to occur in Earth’s atmosphere since the Tunguska event in 1908. It exploded with a force 30 times greater than the atomic bomb that rocked Hiroshima , according to NASA. Video footage of the event showed the space rock burning in a flash of light briefly brighter than the sun, before creating a powerful sonic boom that shattered glass, damaged buildings and injured around 1,200 people in the city below, previously reported on Space.com.
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In a new study, researchers analyzed some of the tiny fragments of space rock left behind after the meteor exploded, known as meteorite dust. Normally, meteors produce a small amount of dust when they burn, but the tiny specks are lost to scientists as they are too small to find, dispersed by the wind, fall into water, or become contaminated by the environment . However, after the Chelyabinsk meteor exploded, a huge plume of dust stayed in the atmosphere for more than four days before finally raining down on the Earth’s surface, according to NASA. And fortunately, layers of snow that fell shortly before and after the event trapped and held dust samples until scientists could recover them soon after.
Researchers came across the new types of crystals while examining dust grains under a standard microscope. One of these tiny structures, which was barely large enough to be seen under a microscope, was fortuitously in focus in the center of one of the slides when a team member looked through the eyepiece. Had it been anywhere else, the team likely would have missed it, according to Sci-News (opens in a new tab).
After analyzing the dust with more powerful electron microscopes, the researchers found many more of these crystals and examined them in much greater detail. However, even then, “finding the crystals using an electron microscope was rather difficult due to their small size,” the researchers wrote in their paper, published May 7 in The European Physical Journal Plus. (opens in a new tab).
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The new crystals came in two distinct forms; near-spherical or “almost spherical” shells and hexagonal shafts, both of which were “unique morphological features,” the researchers wrote in the study.
Further analysis using X-rays revealed that the crystals were made up of layers of graphite – a form of carbon made up of overlapping sheets of atoms, commonly used in pencils – surrounding a central nanocluster at the heart of the crystal. The researchers propose that the most likely candidates for these nanoclusters are buckminsterfullerene (C60), a cage-like ball of carbon atoms, or polyhexacyclooctadecane (C18H12), a molecule composed of carbon and hydrogen.
The team suspects the crystals formed under the high temperature and high pressure conditions created by the meteor’s breakup, although the exact mechanism is still unclear. In the future, scientists hope to track down more samples of meteorite dust from other space rocks to see if these crystals are a common byproduct of meteor ruptures or are unique to the Chelyabinsk meteor explosion.
Originally posted on Live Science. (opens in a new tab)