首页
财务会计
医药卫生
金融经济
考公考编
外语考试
学历提升
职称考试
建筑工程
IT考试
其他
登录
职称考试
Eta Carinae As possibly the galaxy’s (银河)most massive star, Eta Carinae is...
Eta Carinae As possibly the galaxy’s (银河)most massive star, Eta Carinae is...
admin
2020-12-24
53
问题
Eta Carinae
As possibly the galaxy’s (银河)most massive star, Eta Carinae is now engaging in some very unusual behaviour. Australian astronomers, being in the Southern Hemisphere(半球),are at)le to observe it clearly.
In the 19th century, Eta Carinae was for a time the third brightest star in the sky. It has now become less bright so that binoculars ( 双筒望远镜)are needed to see it. “ It seems to be brightening and becoming less bright over a period of many years” ,said Dr Bob Duncan
from the Australia Telescope National Facility.
While it is not unusual for stars to vary in brightness, the period is usually much shorter. “ Since 1992 it has become four times brighter,and then last year it began to drop dramatically, he said.
The problem in observing Eta Carinae is that it has been surrounded by a cloud of gas and dust, making it hard to see the star directly. However, radio waves and infrared light (红外线)can pass through this cloud,so telescopes that receive these wavelengths can observe what is occurring.
Eta Carinae is of particular interest to astronomers because it seems to be in its death throes (剧痛). Being so large it will end up as a supernova (超新星). There has not been a supernova in our geilaxy since the invention of the telescope. While a 1987 explosion in a nearby galaxy gave astronomers plenty of valuable data, they are hungry for an even closer look.
Eta Carinae has other unique features, and is the only star known to produce an ultraviolet (紫外线)laser that is brighter than that produced by the Sun. Lasers have been observed in other frequencies from a few stars.
Astronomers are particularly interested in Eta Carinae because
选项
A it is in its final stage.
B it is a supernova.
C it exploded in 1987.
D it is brighter than the Sun
答案
A
解析
转载请注明原文地址:https://ti.zuoweng.com/ti/wbsQKKKQ
相关试题推荐
Thecourageousboyhasbeenthesubjectofmassivemediacoverage.A:extensiveB:
Exercisewillpossiblyprotectagainstheartattacks.A:usually B:roughlyC:prob
SoMany“Earths” TheMilkyWay(银河)containsbillionsofEarth-sizedplanet...
SoMany“Earths” TheMilkyWay(银河)containsbillionsofEarth-sizedplanets...
SoMany“Earths” TheMilkyWay(银河)containsbillionsofEarth-sizedplanets...
SoMany“Earths” TheMilkyWay(银河)containsbillionsofEarth-sizedplanets...
SoMany“Earths” TheMilkyWay(银河)containsbillionsofEarth-sizedplanets...
SoMany“Earths” TheMilkyWay(银河)containsbillionsofEarth-sizedplanets...
EtaCarinae Aspossiblythegalaxy’s(银河)mostmassivestar,EtaCarinaeis...
EtaCarinae Aspossiblythegalaxy’s(银河)mostmassivestar,EtaCarinaeis...
随机试题
不属于等幅中频电疗法治疗作用的是 A.镇痛 B.兴奋神经肌肉 C.促进血液
属于关系社会公共利益、公众安全的基础设施的项目是()。
科学精神就是一种合理的怀疑精神,以怀疑精神开辟通往真理的道路。它曾怀疑过不许触
(2016年真题)甲公司经营A、B、C三项不同业务,为改进业务发展策略,甲公
李先生将10000元存入银行,假设银行的5年期定期存款年利率是6%,按照单利计算
绞吸挖泥船在()情况下分段施工。 A.挖槽长度大于挖满一舱所需长度时 B.
26岁男患,突发寒战,体温39℃左右,腹泻十余次,伴里急后重,大便病初为稀便,
患儿,2岁,护士为其进行头皮穿刺的时候,应采用的合适距离是A.亲密距离B.社交距离C.个人距离D.公众距离E.空间距离
某证券公司获得了中国证监会的批准,为期货公司提供中间介绍业务。[2013年3月真题] 根据上述事实,请回答以下问题。 根据相关法律规定,该证券公司...
银行资本发挥的作用比一般企业资本发挥的作用更为重要,下列不属于银行资本作用的是()。A.避免损失B.维持市场信心C.限制业务过度扩张D.满足银行正