![]() These grains are like a corpse’s gold tooth, said Schmitz. The chemical barrage left behind grains of chromite, an extremely hardy mineral that composes about 0.25% of some meteorites by weight. “The reaction between pyrite and nitric acid is quite spectacular.” Some of the reactions that ensued were impressive, said Terfelt, who recalled black smoke filling their laboratory’s fume hood. METEOROID THAT STRIKES EARTH WINDOWSThey immersed their samples of limestone-representing 15 different time windows spanning from the Late Cambrian to the early Paleogene-in successive baths of hydrochloric acid, hydrofluoric acid, sulfuric acid, and nitric acid to dissolve the rock. METEOROID THAT STRIKES EARTH SERIESSchmitz and Terfelt used a series of strong chemicals in a specially designed laboratory to isolate the extraterrestrial material. “Ordinary chondritic asteroids don’t even appear to be common in the asteroid belt.” They’re not interested in the rock itself, which was once part of the ancient seafloor, but rather in what it contains: micrometeorites that fell to Earth over the past 500 million years. Inspired by that experience, Schmitz and his Lund University colleague Fredrik Terfelt, a research engineer, have spent the past 8 years collecting over 8,000 kilograms of sedimentary limestone. Get the most fascinating science news stories of the week in your inbox every Friday. “It was the first insight that we could get astronomical information by looking down instead of looking up,” said Schmitz. It was the 1980s, and he was studying the Chicxulub impact crater. ![]() Astronomy by Looking Downīirger Schmitz, a geologist at Lund University in Sweden, remembers the first time he looked at sediments to trace something that had come from space. ![]() ![]() That’s a surprise, the team suggested, because it’s long been believed that random collisions of asteroids in the asteroid belt periodically send showers of meteoroids toward Earth. The vast majority of it is too small to see with the naked eye, but even bits of cosmic dust have secrets to reveal.īy poring over more than 2,800 grains from micrometeorites, researchers have found that the amount of extraterrestrial material falling to Earth has remained remarkably stable over millions of years. Thousands of tons of extraterrestrial material pummel Earth’s surface each year. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |