A piece of meteorite. The beads of glass inside the meteorites are called chondrules. Scientists think they are bits of rock that were floating around billions of years ago, which eventually coalesced into the planets we now know and love. Credit: James St. John.
Scientists have been fascinated by what's inside meteorites since they started looking at them with microscopes. Most meteorites are made of tiny beads of glass that are from the earliest days of the solar system.
The University of Chicago has published an analysis on how these beads came to be in meteorites, and how they can tell us about what happened in the early solar system.
Nicole Xike Nie, a graduate of the University of Chicago, is the first author of the study. meteorites can reveal the conditions that the early dust experienced, which has implications for the evolution of both Earth and other planets.
This question has been asked for 50 years.
The beads of glass inside the meteorites are called chondrules. Scientists think they are bits of rock that were floating around billions of years ago, which eventually coalesced into the planets we now know and love. The pieces of the original stuff that made up the solar system can be found in these.
What caused the formation of these chondrules is not known.
"We have the same theories we had 50 years ago," said study co-author and UChicago researcher. This one has been stubborn even though there have been advances in other areas.
Scientists can look at the types of elements in a rock to find clues about the early days of the solar system. When a rock is born, the proportion of elements in it varies depending on how hot it was, whether it cooled slowly or was flash-frozen, and what other elements were around to interact with it. Scientists can piece together a history of likely events from there.
The scientists at the UChicago tried to understand what happened to the chondrules by applying a unique angle to the isotopes.
The possibilities of what could have happened in the early solar system were narrowed down by the precise measurement of the concentrations and isotopes of two elements that are in meteorites.
The team pieced together what happened as the chondrules formed. The elements would have been part of a clump of dust that got hot enough to melt and then to evaporate. Some of the vapor coalesced back into chondrules as the material cooled.
"We can tell you how fast it cooled, because it was fast enough that not everything fell apart," said Nicolas Dauphas, Professor of Geophysical Sciences at UChicago. The temperature was dropping at a rate of 500 degrees per hour, which is really fast.
Scientists can theorize what kind of event would have caused this extreme heating and cooling based on the constraints. Massive shockwaves passing through the early nebula is a scenario that would fit. Large planetary bodies nearby can 888-269-5556 888-269-5556 888-269-5556s, which would have heated and cooled the dust as it passed through.
Over the past half-century, people have proposed different scenarios to explain the formation of the chondrules, but this new evidence suggests that the balance should be shifted to shockwaves.
This explanation may be the key to understanding a persistent finding that has bedeviled scientists for decades, involving a category of elements that are moderately volatile. The Earth has less of these elements than scientists think it does. They knew the explanation could be traced to a complex chain of heating and cooling, but no one knows the exact sequence. It's a big question in the field of chemistry.
The team is happy to have put an end to the mystery.
"We know other processes happened, but this really solved one step in the formation of planets," said Hopp.
It's cool to be able to say what happened.
The University of Washington and the Carnegie Institute for Science were both involved in the paper.
The Imprint of chondrule formation on the K and Rb isotopic compositions of carbonaceous meteorites was reported in Science Advances. There is a DOI: 10.126/sciadv.abl3929.
Science Advances has journal information.
The beads of glass in meteorites were retrieved from December 2nd to December 2nd.
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