Meteors that have crashed to Earth have long been regarded as relics1 of the early solar system. These craggy chunks2 of metal and rock are studded with chondrules -- tiny, glassy, spherical3 grains that were once molten droplets4. Scientists have thought that chondrules represent early kernels5 of terrestrial planets: As the solar system started to coalesce6, these molten droplets collided with bits of gas and dust to form larger planetary precursors7. However, researchers at MIT and Purdue University have now found that chondrules may have played less of a fundamental role. based on computer simulations, the group concludes that chondrules were not building blocks, but rather byproducts of a violent and messy planetary process.The team found that bodies as large as the moon likely existed well before chondrules came on the scene. In fact, the researchers found that chondrules were most likely created by the collision of such moon-sized planetary embryos8: These bodies smashed together with such violent force that they melted a fraction of their material, and shot a molten plume9 out into the solar nebula10. Residual11 droplets would eventually cool to form chondrules, which in turn attached to larger bodies -- some of which would eventually impact Earth, to be preserved as meteorites12.Brandon Johnson, a postdoc in MITs Department of Earth, Atmospheric13 and Planetary Sciences, says the findings revise one of the earliest chapters of the solar system.This tells us that meteorites arent actually representative of the material that formed planets -- theyre these smaller fractions of material that are the byproduct of planet formation, Johnson says. But it also tells us the early solar system was more violent than we expected: You had these massive sprays of molten material getting ejected out from these really big impacts. Its an extreme process.Johnson and his colleagues, including Maria Zuber, the E.A. Griswold Professor of Geophysics and MITs vice14 president for research, have published their results this week in the journal Nature.
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1 relics [pl.］n.遗物，遗迹，遗产；遗体，尸骸 参考例句： The area is a treasure house of archaeological relics. 这个区域是古文物遗迹的宝库。 Xian is an ancient city full of treasures and saintly relics. 西安是一个有不少宝藏和神圣的遗物的古老城市。
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