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
13
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] 【C5】
选项
A、desirably
B、obviously
C、efficiently
D、simply
答案
C
解析
efficiently意为“高效的”。此处意为“自然界出产金刚石要比我们人类生产金刚石效率高得多”。
转载请注明原文地址:https://tihaiku.com/zcyy/3199049.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
Theconcertowasperformedbyaviolinistofunquestioned______butlimitedima
随机试题
A、Hestilllivedinhiscollegedormroom.B、Hemadealivingbysellingwinebo
在战争制胜问题上,()是决定因素,无论时代条件如何发展,战争形态如何演变,这一
下列属于普通年金形式的项目有()。A.定期定额支付养老金 B.偿债基金 C.
某企业五年前利用贷款购置设备,贷款1500万元,年利率7%,第5年年末一次还本付
斜拉桥主跨振型排序与简支梁的基本一致。
从所给四个选项中,选择最合适的一个填入问号处,使之呈现一定的规律性: A.
肝素静脉给药的原因是A.口服首过效应消除明显B.大分子并带大量负电荷C.胃中易被
在个人住房贷款业务中,贷后管理工作不包括()。A.合同签约 B.贷款档案
全面依法治国,需要解决法治建设不适应、不符合推进国家治理体系和治理能力现代化目标
2018年6月6日,甲公司在P银行开立主办账户,并与其签订协议开通
最新回复
(
0
)