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
20
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] 【C7】
选项
A、at
B、by
C、against
D、besides
答案
B
解析
by意为“通过”。此句意为“尽管以前也发现过陨星内含有金刚石,但它们是在相对近期内通过猛烈撞击形成的”。
转载请注明原文地址:https://tihaiku.com/zcyy/3199051.html
相关试题推荐
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Trillionsofincrediblytinydiamonds,possiblyformedbyadyingstarbefo
Theconcertowasperformedbyaviolinistofunquestioned______butlimitedima
WhichofthefollowingwillNOTpossiblyleadtoheartdisease?[br][originalt
WhichofthefollowingwillNOTpossiblyleadtoheartdisease?[br][originalt
随机试题
[originaltext]W:Goodafternoon,everybody.Justweeksago,hardlyanyoneinth
Doyoumind______theradioon?A、metoturnB、meturningC、myturnD、myturning
I’dratherhavearoomofmyown,howeversmallitis,______(也不愿和别人同住一间屋).thans
A.耻骨联合上缘中点至骶岬上缘中点间的距离 B.耻骨联合下缘至骶岬上缘中点间的
企业对新产品实行撇脂定价,一般应具备()等条件。 A.竞争者容易加入
对于人民法院认为起诉不符合起诉条件作出的不予受理裁定,原告不服的,可以()。A、
我们所要建设的社会主义和谐社会,应该是民主法治、公平正义、诚信友爱、充满活力、安
假设一国商业银行某年末的财务数据如下: 该银行的资本充足率是( )。A.
价值工程中的“价值”是相对概念,它是对象的()价值.A、使用 B、交换 C
男,35岁。左下腹外伤后24小时。入院时有弥漫性腹膜炎,行剖腹探查术。术中见腹腔
最新回复
(
0
)