皮皮学,免费搜题
登录
logo - 刷刷题
搜题
【单选题】
How the First Stars in the Universe Came into Existence Researchers believe that our universe began with the Big Bang(宇宙大爆炸)about 13 billion years ago,and that soon after that event,matter began to form. as small dust grains and gases.How the first stars formed from this dust and gas has been a burning question for years,but a state of-the-art computer simulation now offers the most detailed picture yet of how these first stars in the universe came into existence. The composition of the early universe was quite different from that of today,and the physics that governed the early universe were also somewhat simpler.Dr.Naoki Yoshida and colleagues in Japan and the U.S.incorporated these conditions of the early universe,sometimes referred to as the“cosmic dark ages,”to simulate the formation of an astronomical object that would eventually shine its light into this darkness. The result is a detailed description of the formation of a protostar(原恒星)-the early stage of a massive primordial(原始的)star of our universe-and the researchers'computer simulation sets the bar for further investigation into the star formation process.The question of how the first stars evolved is so important because their formations and eventual explosions provided the seeds for subsequent stars to come into being. According to their simulation,gravity acted on minute density variations in matter,gases,and the mysterious“dark matter”of the universe after the Big Bang in order to form. this early stage of a star-a protostar with a mass of just one percent of our sun.The simulation reveals how pre-stellar(前恒星的) gases would have actually evolved under the simpler physics of the early universe to form. this protostar. Dr.Yoshida's simulation also shows that the protostar would likely evolve into a massive star capable of synthesizing(合成)heavy elements,not just in later generations of stars,but soon after the Big Bang. Their simulation of the birth of a protostar in the early universe signifies a key step toward the ambitious goal of piecing together the formation of an entire primordial star and of predicting the mass and properties of these first stars of the universe.More powerful computers,more physical data,and an even larger range will be needed for further calculations and simulations,but these researchers hope to eventually extend this simulation to the point of nuclear reaction initiation-when a stellar(星球的)object be comes a true star. According to the first two paragraphs,the early universe
A.
was governed by simpler physics.
B.
got fewer stars shinning in it.
C.
started over 13 billion years ago.
D.
was composed in a way similar to that of today.
手机使用
分享
复制链接
新浪微博
分享QQ
微信扫一扫
微信内点击右上角“…”即可分享
反馈
参考答案:
举一反三
【单选题】甲公司与乙公司、丙公司串通,以事先约定的时间、价格和方式相互进行证券交易,影响证券交易价格或者证券交易量。这种行为属于()
A.
内幕交易行为
B.
操纵市场行为
C.
虚假信息传播行为
D.
欺诈客户行为
【判断题】( )家庭对每一个成员的消费行为影响至关重要。A. 对 B. 错
A.
正确
B.
错误
【单选题】“毒奶粉”事件再次提醒我们要注意食品安全,下列有关食品加工方法安全的是
A.
用工业盐(含NaNO 2 )来做食品添加剂
B.
用塑料颗粒来制作珍珠奶茶中的“珍珠”
C.
用工业酒精勾兑水来生产低成本白酒
D.
用小苏打来作焙制糕点的发酵粉成分
【单选题】“奶粉”事件再次我们要注意食品安全,下列有关食品加工方法安全的是
A.
用工业盐(含NaNO 2 )来做食品加剂
B.
用小苏打 NaHCO 3 )来作焙制糕点的发酵粉成分
C.
用工业酒精勾兑水来生产低成本白酒
D.
用塑料颗粒来制作珍珠奶茶中的“珍珠”
【判断题】家庭对每一个成员的消费行为影响至关重要
A.
正确
B.
错误
【单选题】丙公司串通,以事先约定的时间、价格和方式相互进行证券交易,影响证券交易价格或者证券交易量。这种行为属于( )
A.
内幕交易行为
B.
操纵市场行为
C.
虚假信息传播行为
D.
欺诈客户行为
【单选题】产品质量保证保险与产品责任保险的共同点是。
A.
两者都负责赔偿产品本身的损失。
B.
两者都带有担保性质
C.
两者都与产品的质量有关。
D.
两者都以产品质量为保险标地。
【单选题】甲公司与丙公司串通,以事先约定的时间、价格和方式相互进行证券交易,影响证券交易价格或者证券交易量。这种行为属于( )
A.
内幕交易行为
B.
操纵市场行为
C.
虚假信息传播行为
D.
欺诈客户行为
【单选题】产品质量保证保险与产品责任保险的共同点是。
A.
两者都负责赔偿产品本身的损失。
B.
两者都带有担保性质
C.
两者都与产品的质量有关。
D.
两者都已成品责任为保险标地。
【判断题】家庭对每一个成员的消费行为影响至关重要。
A.
正确
B.
错误
相关题目:
参考解析:
知识点:
题目纠错 0
发布
创建自己的小题库 - 刷刷题