首页
登录
职称英语
Trillions of incredibly tiny diamonds, possibly formed by a dying star befo
Trillions of incredibly tiny diamonds, possibly formed by a dying star befo
游客
2023-11-18
12
管理
问题
Trillions of incredibly tiny diamonds, possibly formed by a dying star before the solar system was born 4.5 billion years ago, have been found by researchers 【C1】______ four meteorites.
The powder-like diamonds could be among the oldest things in the 【C2】______ , said Roy Lewis, senior research associate at the University of Chicago.
The diamonds may 【C3】______ clues about the chemistry of stars, and if scientists can determine how they formed, that could suggest better ways of manufacturing tiny diamonds for 【C4】______ purposes, he said.
"It’s quite possible that nature is doing it more 【C5】______ than we’ve been doing it," he said. "So maybe we’ve got something to learn."
The new find is 【C6】______ , said John Wood, staff scientist at the Harvard-Smithsonian Centre for Astrophysics. Although diamonds have been found before in meteorites, they were formed relatively recently 【C7】______ the shock of impact, he said in a telephone interview.
But Wood said the new report made him "quite sure" the newly found diamonds are older than the sun.
Lewis said researchers never expected to find diamonds when they started 【C8】______ a stone-like meteorite that had plunged into Mexican cornfield in 1969.
They were studying an unusual carbon dust in the meteorite, and to purify the sample they went though several steps to dissolve other materials. They expected the sample to remain black through the purification, but to their surprise in the final step it turned 【C9】______ .
Lewis said they believed the final stage had dissolved the carbon they wanted to study. But tests showed that the white residue was in fact made of carbon. Other tests found that it contained an unusual combination of forms of the gas xenon, 【C10】______ that it came from outside the solar system.
Still another battery of tests 【C11】______ the residue as diamond dust, so fine that a row of 20,000 grains would extend about the 【C12】______ of a human hair.
The researchers also found diamonds in three other meteorites, Lewis said. Tests showed all four meteorites were as old as the solar system, and that the embedded diamonds did not form within the meteorite 【C13】______ of collisions.
So the diamonds must have 【C14】______ somewhere else before the meteorites formed, making them as old or older than the solar system.
The diamonds may have formed in the upper atmosphere of a star in the late "red giant" stage, where the temperature and abundance of hydrogen could 【C15】______ diamonds to form as carbon gas condenses. [br] 【C14】
选项
A、risen
B、disappeared
C、arisen
D、encountered
答案
C
解析
arise“出现”,该句意为“早在陨石形成之前,金刚石就应该已经形成了”。
转载请注明原文地址:https://tihaiku.com/zcyy/3199058.html
相关试题推荐
Inaphysicalchangenonewsubstanceisformed,______inthecompositionofmat
Theenergy______bythechainreactionistransformedintoheat.A、entrustedB、r
Peopleunderstresshaveperformed______featsofstrength,likeliftinganaut
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
随机试题
[originaltext](29)Isittruethatyouwillfeelveryexcitedandhappywhen
ItcanbeinferredthatMichaelTenet’sattitudetowardglobalizationisprobabl
根据《普通高等学校辅导员培训计划》,继续选拨辅导员在职攻读思想政治教育专业博士学
试分析错误观念及其对教学的启示。
A.6kN B.10kN C.12kN D.15kN
下列因素中,归属影响药品质量的人为因素的是A.药品贮存时间 B.药品质量监督管
下列各项资产减值准备中,在相关资产持有期间内可以通过损益转回的有()。
甲担保公司为乙某购买住房贷款提供担保,委托丁保险经纪公司向丙保险公司为其提供
下列关于分部分项工程量清单的说法中,正确的是()。A.清单为可调整的开口清单
共用题干 40岁经产妇,近2年出现痛经并逐渐加重,伴经量增多及经期延长,需服强
最新回复
(
0
)