24、 太阳起源——太阳的产生不是孤立的,而是一系列超新星爆炸的产物 (这篇读着比较累,1.5屏) ;很长。730强推荐只看有nikon60的那段,题目基本都在p2 P1: 科学家在陨石上发现一些矿物,可以证明太阳在新生时曾与一supernova非常接近。进而推测太阳是原来在一个cluster里,在clusterexplosion中产生的,而非像现在一样远离其它galaxies。P2: 然后作者开始证明。科学家对两个meteorite的样本进行了化验,发现了iron和nickle60的物质,这种nickle由iron衰变而来。(1.问科学家研究的meteorite样本?)一般来说,离什么中心越远,重金属含量越少,离中心越近,成分越rich。所以如果太阳had been secluded(隔离),那么就不会有这些物质,所以iron60一定是太阳旁边的一个超新星爆炸时,喷射的距离一定很近以使iron的温度不致太快冷却。所以证明作者结论,以此来证明太阳来自cluster。 P3: (有一段oddly开头的好像没有考到)太阳系有些彗星comet的运行轨道很odd。作者解释是被其他一些类似太阳的星球带的,再次证明作者结论太阳是从a cluster ofstar来的。 P4: 讲从行星的orbit 还有comets 来分析,太阳是来自其他地方的exploding。 P5: 最后文章说天文学家进一步研究。正在太阳多少范围内的arc上寻找有没有别的太阳一样的星星。若有,他们应该和太阳一样受到那个爆炸的超新星的物质辐射(问文章最后一段的作用?)正确选项就是获得更多证据来证实上文观点之类的。讲了一个宇航员的什么观点,在寻找新的证据。 Q&A 1.问科学家研究的meteorite样本? 我选的是上面发现的nickel60是从iron60衰变来的; 【干扰选项】primarily consistof nickel 60.不对!720 2.如果观察到的现象不是这样的话会发生什么事?选项有: 那么太阳产生的时候就是应该是和stars们成一个 cluster; 那么太阳和stars就会disperse什么的710 3.主旨 选太阳起源于cluster V37 4. 然后就问了最后一段的作用? 正确选项就是获得更多证据来证实上文观点之类的。选provide another evidence to supportthe explaination740 5.问宇航员找到以下哪个证据会weaken科学家的研究?v30 背景知识1:
· The sun is a solitary star, and astronomershave traditionally assumed it formed as such. Yet most stars are born inclusters, and scraps of evidence from meteorites and from the arrangement ofcomets suggest that our sun was no exception.
· This suggests to Bizzarro and his colleaguesthat iron-60was added to the cloud of gas and dust surrounding the primitive Sun(the protoplanetary原行星盘disk) about 1 million years after the Solar System formed. This could happen ifthe Sun's nursery contained massive stars (perhaps 30 times the mass of theSun). Such stars last only about 4 million years. They are extremely active,blowing away their outer layers in the last million years of existence. Thedispersed material would have included aluminum-26 and might have causedcollapse of interstellar星际的gas and dust to cause formation of the Sun and its protoplanetary disk. A millionyears later the massive star exploded, ejecting iron-60 from its interior.Bizzarro and colleagues argue that this huge event of destruction and creation isrecorded in the meteorites.
· Scrap 碎片 小片meteorite 陨星 nickel 镍 supernova超新星 seclude隔绝
太阳爆炸 背景知识 2 Astronomicobservations with the latest and greatest telescopes are leading astronomers toembrace the idea that stars usually form in clusters, even if they end up, likeour Sun, isolated from other stars. Cosmochemists using optical microscopes,electron microscopes, and mass spectrometers are finding evidence supportingthe idea, along with important details about the star-forming regions and aboutthe earliest history of the Solar System. The latest breakthrough is reportedby Martin Bizzarro and his colleagues at the Geological Institute and Geological Museum
in Denmark, at the University of Texas,and at Clemson Universityin South Carolina.They made high-precision measurements of iron and nickel isotopes. The resultsshow that the oldest planetesimals to form in the solar system did not containany iron-60 ( 60Fe), which decays to nickel-60 ( 60Ni) with a half-life of only 1.5 million years,yet somewhat younger materials did contain it. In contrast, aluminum-26 ( 26Al), with a half-life of740,000 years, was relatively uniformly distributed. The 60Fe cannot have come from a source too far from the infant Sun. If too faraway it would decay before arriving or be so diluted that we could not measureit. The exploding star had to be in the Sun's general vicinity. It was a cluster mate of the Sun. One type of massive star is called aWolf-Rayet star (named after the discoverers). In these large objects, elements formed inside by nuclear fusion,such as oxygen and aluminum, migrate toward the surface. This concentration ofmaterial begins to adsorb light from inside, eventually resulting in strongwinds blowing off the surface and into interstellar space. The winds are shownin the image, below, taken in the infrared. Astronomers believe that most massivestars (those >20 times the mass of the Sun) go through a Wolf-Rayet phase,which ends when they explode as supernova.
看着以前整的花花绿绿的真恶心,真想全部重弄,(一战没经验,大家原谅我),不过没时间啦; 哎呀,鄙视自己 ,又跑来,数学做完了再滚回来 |