| 单词 | chondrule |
| 例句 | The chemical composition of chondrules can help scientists understand the structure and composition of the nebula of gas and dust from which the planets and asteroids formed. A Meteorite Fell in Their Bedroom. Here’s What Happened Next 2023-05-25T04:00:00Z "The mission will proceed over several phases with the introduction of different types of particles into the ETC, beginning with large solid spherical particles, and finishing with aggregates of micron-sized dust and chondrules." All the space exploration missions to look forward to in 2021 2020-12-30T05:00:00Z Against such magnificent achievements, the stubborn enigma of the lowly chondrule seems to shrink even smaller than its already niche status. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z To form, chondrules must be heated and then cooled rapidly, a scenario that is difficult to explain. Small Worlds With Lava Oceans Might Have Given Us Meteorites 2020-06-22T04:00:00Z At the same time, chondrites—common stony meteorites—are also peppered with rounded, shiny inclusions known as chondrules, some of which are iron-nickel rich. NASA to Seek Iron-Spewing Volcanoes at Psyche 2019-04-25T04:00:00Z There is some evidence that small clumps are the fundamental building blocks: Many asteroids are made of chondrules, small beads on the scale of a centimeter or less. 'Dinosaur eggs' spotted on Rosetta’s comet 2014-12-18T05:00:00Z The vast majority are chondrites, pieces of asteroids filled with little glassy beads called chondrules. Feature: A castaway from ancient Mars 2014-11-25T05:00:00Z The main problem is finding a model that can explain all the different, diverse properties of chondrules. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z That rapidly melted portions of these objects, which then passed by and cooled to form chondrules. Small Worlds With Lava Oceans Might Have Given Us Meteorites 2020-06-22T04:00:00Z The scientists discovered the chondrules were magnetized in a field roughly 54 microtesla in strength. Meteorite Bears Evidence of Magnetic Fields in Early Solar System 2014-11-14T05:00:00Z Fu's team studied eight chondrules—small pellets of rock—in the meteorite, focusing on dusty olivine grains that contain metal, which, like compasses, aligned with the nascent solar system's magnetic field. First measurement of the ancient solar system's magnetic field 2014-11-13T05:00:00Z These “relict” grains are not simply unmelted host chondrule material; they were derived from a preexisting earlier generation of chondrules. Readers Respond to "The Myth of Antioxidants" 2013-06-14T14:15:00.310Z The nebula shock model, meanwhile, posits that Mars-sized planetary embryos moving through the nebula could act like boats sailing through water, fusing dust into chondrules. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z But without a clear way to explain chondrules at the moment, every hypothesis is on the table. Small Worlds With Lava Oceans Might Have Given Us Meteorites 2020-06-22T04:00:00Z Still, analyzing the magnetic signatures of these chondrules was not easy. Meteorite Bears Evidence of Magnetic Fields in Early Solar System 2014-11-14T05:00:00Z As the researchers report online today in Science, the chondrules formed in a magnetic field that was about half a gauss strong, comparable to the value at Earth's surface today. First measurement of the ancient solar system's magnetic field 2014-11-13T05:00:00Z In “Secrets of Primitive Meteorites,” Alan E. Rubin mentions the search for a heating process in the early solar system that would partly melt dust to form the layered chondrules found in meteorites. Readers Respond to "The Myth of Antioxidants" 2013-06-14T14:15:00.310Z Other ideas include radiative heating, a relatively new idea that suggests planetesimals flying low over molten bodies could have been roasted and then cooled to produce chondrules. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z “Most people would be absolutely stunned if there weren’t any chondrules in those materials,” Dr. Jones said. Small Worlds With Lava Oceans Might Have Given Us Meteorites 2020-06-22T04:00:00Z They found the meteorite's chondrules probably formed either as molten debris from the collisions of rocky bodies or from dust particles within gas melting together when they were compressed by a shock wave. Meteorite Bears Evidence of Magnetic Fields in Early Solar System 2014-11-14T05:00:00Z No two chondrules are alike, Rubin says; in that sense, “they are like snowflakes.” Fall That Glitters: Microscopy Reveals Stained-Glass Beauty in Ancient Meteorites [Slide Show] 2013-01-23T13:15:00.190Z An energy source capable of melting just the outer part of a chondrule and not an interior relict grain is required. Readers Respond to "The Myth of Antioxidants" 2013-06-14T14:15:00.310Z Even so, many models still remain, complicated by the fact that chondrules are not really predicted by planet formation at all. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Huss, a cosmochemist at the University of Hawaii, says chondrule formation would appear to be a required step to form planetary bodies of more than a meter in size. Planets Made Easy: The Cosmic Glue That Binds Us All 2012-09-30T11:10:48Z Semarkona is made up mostly of tiny round pellets known as chondrules, which formed as molten droplets that quickly cooled in space. Meteorite Bears Evidence of Magnetic Fields in Early Solar System 2014-11-14T05:00:00Z In the slices most of the colored bits are either full or fragmented chondrules or they are grains of olivine or pyroxene that were released from chondrules that broke open. Fall That Glitters: Microscopy Reveals Stained-Glass Beauty in Ancient Meteorites [Slide Show] 2013-01-23T13:15:00.190Z It is also a common constituent of meteoric stones, forming with olivine the bulk of the material: here it often forms small spherical masses, or chondrules, with an internal radiated structure. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 6 "English Language" to "Epsom Salts" 2011-02-19T03:00:59.807Z If true, this would suggest that the story of our solar system’s turbulent history is stored within chondrules themselves, offering yet another reason to lavish them with careful attention. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Hayabusa2 is not the only sample return mission with extraterrestrial gifts in store for chondrule scientists. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z These findings also yield insights on the as-yet-mysterious way in which chondrules form, which in turn may shed light on how planets arise, the researchers said. Meteorite Bears Evidence of Magnetic Fields in Early Solar System 2014-11-14T05:00:00Z A variant of this, called splashing, would have involved collisions between molten objects at lower velocities, releasing droplets into space that solidified into chondrules. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z “The chondrule precursors, this dust, is heated by entering this compressed hot gas and is processed by it.” Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z While not definitively linked to the formation of chondrules, the observation at least showed that suitably energetic collisions to make them do seem to occur in young systems. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z At stake is what role chondrules played in our solar system. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Understanding chondrule formation could, in other words, reveal our solar system’s earliest moments. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Essentially rocks within rocks, chondrules appear as rounded flecks in chondritic meteorites. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Ordinary chondrites, for example, are chock full of chondrules and account for more than nine out of every 10 chondrule-containing space rocks. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z In the future, we should also be able to better probe the distribution of dust around young stars with higher resolution images, letting us possibly refine some models of chondrule formation. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z The problem of chondrules has from the start been intergenerational, inspiring one cohort after another to try their hand at tackling the issue, with varying success. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z To make chondrules, dust must have been heated to temperatures of up to 2,000 degrees Celsius by some process in the early solar system, before rapidly cooling over just days or even hours. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z This process, whatever it was, likely occurred throughout the solar system, in order to account for the large abundance of chondrules found in chondrites on Earth. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Most chondrule scientists fall into one of two camps. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Made of minerals such as olivine and pyroxene, and sometimes glass, chondrules themselves come in a variety of shapes, sizes and compositions—often containing a glittering array of crystals. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z The first believes that chondrules were among the first solid objects to appear in the solar system, forming directly from the solar nebula—the cloud of dust and gas that surrounded our young sun. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z In 1802, the British chemist Edward Howard was one of the first scientists to recognize chondrules as “rounded globules” in meteorites. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z “If there were no chondrules, and it looked like there had never been chondrules in them, then maybe chondrule formation is not such a ubiquitous process,” says Russell. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Today there are, the joke goes, as many theories about chondrule formation as there are chondrule scientists themselves—with the acerbic addendum that tomorrow there will inevitably be even more. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z “We can build a story about how planets form without ever invoking chondrule formation,” says Ciesla. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z And the chondrules must also have drifted for a time through the dusty environs around our young sun, to account for the telltale rims of accumulated dust that encase their centers. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Within the first camp, one idea is that gravitational instabilities in the disk of dust and gas around our sun resulted in “shock fronts” that fused some of the dust into chondrules. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Most of our ideas on chondrule formation come from modeling of the early solar system and performing experiments on Earth to replicate different formation methods. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Experiments like these are crucial for understanding chondrules in concert with modeling of the solar system. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z “If we get ones that look similar to the natural chondrules that we’ve studied, then we have a better of idea of how they formed,” Smith says. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z “The experiments are just defining the conditions for chondrules,” says Jones, Smith’s supervisor. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z If chondrules are among the first solids to form around stars, they could be crucial catalysts for subsequent planet formation, in particular the jump from dust-sized to kilometer-sized objects. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z And perhaps chondrules are even more essential; one model of planet formation, pebble accretion, posits that larger bodies swept up pebblelike dust in order to grow into planets. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z “I think that would be shocking to the chondrule community,” says Herbst, overturning any already precarious consensus. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Images from the lander showed many white markings on the surface, which may have been CAIs, but also could have been chondrules. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z In our understanding of how Earth—any planet in the cosmos, in fact—came to be, there may be nothing as important as the mystery of the chondrule. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z “They are stained glass windows to the earliest time period of the solar system,” says Harold Connolly, a cosmochemist and chondrule expert from Rowan University in New Jersey. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z A subgroup called CI chondrites have no visible chondrules, having likely been altered by water. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Because apart from this one anomaly, the exact formation process for chondrules and chondrites remains a mystery—but not for any lack of trying. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z If new types of chondrules are found in the samples, however, that could give us a fresh perspective on the larger problem of origins—and scientists like Connolly favor such a scenario. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Like many before him, Wood had become fascinating by chondrules when he first laid eyes on them. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z “He basically said he’d wasted his entire life working on chondrules, because it was an impossible problem to solve,” says Conel Alexander, a cosmochemist from the Carnegie Institution for Science in Washington, D.C. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z In the other camp, which proposes chondrule formation was post-planetesimal, one of the more prominent models is called impact jetting. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Here, planetesimals would collide at high velocities, creating the necessary heat to produce chondrules. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z And even if chondrules are not present, it could simply suggest Ryugu has been altered by water in its past, erasing any evidence of its chondrules, as with CI chondrites found on Earth. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z Elsewhere, observations of other solar systems—in particular, protoplanetary disks of dust and gas around young stars—are yielding useful information about possible scenarios for chondrule creation. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z “It would be really disappointing if we didn’t find chondrules in the material,” says Connolly, who is also part of the OSIRIS-Rex team. Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z “I’m looking forward to finding chondrules that I know and chondrules that I don’t know.” Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation 2020-12-08T05:00:00Z |
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