用英语写一篇文章介绍宇宙
宇宙的起源和早期演化是人类文明肇始以来不断探寻的重要课题,也是人类文明发展的一个原始和持久的推动力。下面是小编带来的用英语介绍宇宙的文章,欢迎阅读!
用英语写一篇文章介绍宇宙1
科学家认为火星卫星形成于火星大碰撞
Mars is a planet of outsized splendor. Despite being only half as big and a tenth as heavy asEarth, it bears the solar system’s tallest mountain, longest canyon and largest crater. At 22and 12 kilometers wide, however, its inner moon Phobos and outer moon Deimos arefigurative small potatoes. Scientists suspect both formed much as Earth’s single large moondid, from a massive debris disk ejected into orbit by a giant impact eons ago. But if Mars’smoons formed like Earth’s, why are they so very much smaller?
The answer may be that they did not form alone. New simulations from Pascal Rosenblatt of theRoyal Observatory of Belgium and colleagues show how the debris disk from a giant impact onMars could have generated additional moons a few hundreds of kilometers in size. Afterforming in the dense inner regions of the disk, those larger moons would have stirred the disk’ssparser outer reaches, allowing smaller companions like Phobos and Deimos to coalesce fromthe ripples. The study appears in the journal Nature Geoscience.
In this scenario, the reason we only see Phobos and Deimos today is that the bigger moonswere destroyed a few million years after their formation. Their low, fast orbits outpaced Mars’srotation, creating a tidal pull that sent them spiraling down to crash into the planet (Earth’smoon, by contrast, orbited slower than our planet’s rotation, allowing it to spiral outwardand survive). Future investigations could test the new hypothesis by looking for clusters ofMartian craters produced by the infalling moons, but in the meantime, proof that Mars can killits companions is right before our eyes: The orbit of Deimos is stable, but Phobos is in a deathspiral, losing two centimeters of altitude per year to Mars’s tidal pull. It will plunge into theplanet in 20 million to 40 million years, leaving lonely, far-out Deimos as the last vestige ofwhat may have been a once-mighty system of Martian moons.
用英语写一篇文章介绍宇宙2
恒星揭示隐藏星系所在
Four stars near the bright band of the Milky Way have revealed a secret:
the presence of a hidden dwarf galaxy.
Six years ago astronomers predicted that such a galaxy might be in that region based on observed ripples in the Milky Way's disk.
The galaxy is small, faint, and dominated by invisible dark matter.
That combination obviously makes it very hard to see.
Furthermore, it lies behind a shroud of dust that blocks any visible light from passing through.
Now scientists have identified four stars that appear to belong to the galaxy by examining infrared light, which can cut through dust.
The stars are known as Cepheid variables.
They pulse brighter and dimmer in a predictable pattern, which allows astronomers to determine how far they are from us—about 300,000 light years.
That distance puts them well beyond the main body of the Milky Way and right where an orbiting dwarf galaxy might lie.
The finding is in the Astrophysical Journal Letters.
Dwarf galaxies like this one are thought to contain more dark matter than regular matter.
So tracking down such dwarfs could give researchers more clues in the quest to figure out what dark matter is made of.
银河系亮带附近的4颗恒星揭示了一个重大秘密:
那就是一个隐藏矮星系的存在。
天文学家们曾在6年前根据银河系盘面观察到的涟漪推断该区域可能存在一个星系。
他们推断这是个很小且很微弱的星系,而且主要是由不可见的暗物质组成。
这样特征的星系大大增加了观测难度。
此外在它前面还有一层阻隔任何可见光线通过的尘埃。
而现在科学家们通过检测可穿透尘埃的红外线已经发现了4颗似乎属于这个星系的恒星。
这些恒星就是我们熟知的造父变星。
在一种可预测的模式中,它们一亮一暗的节奏使得天文学家能够确定它们距离我们究竟有多远—约30万光年。
这样的距离使它们远于银河系主体,正好位于一个矮星系轨道的所在。
这一发现已经在《天体物理学》杂志上发表。
像这样的矮星系含有的暗物质比普通物质要多。
所以追踪这种矮星系能为研究人员研究暗物质的组成提供更多线索。
用英语写一篇文章介绍宇宙3
夏威夷大学定义超星系团兰天
We finally know our cosmic address.
我们终于搞清楚了宇宙的所在。
For the first time, astronomers have identified our home supercluster—a conglomeration of groups of galaxies and larger clusters of galaxies, all interconnected in a stringy web.
天文学家第一次发现了我们的宇宙家园超星系团,这是星系团和较大星系群的一种聚集体,其中所有星系都是相互联系的网络。
Researchers, led by an astronomer at the University of Hawaii at Manoa, have named this supercluster Laniakea, which means “immense heaven” in Hawaiian.
在夏威夷马诺亚大学一位天文学家领导下的研究人员们将此超星系团命名为兰天,夏威夷语意思是“广袤无垠的天堂”。
Laniakea encompasses 100,000 galaxies stretched out over 500 million light-years.
兰天超星系团内部包含10万个星系,延伸5亿光年的距离。
Our own Milky Way is just one of these.
我们的银河星系就是其中一个星系。
The study is in the journal Nature.
这项研究已经在《自然》杂志上发表。
Superclusters are some of the universe's largest structures, and have boundaries that are tough to define—especially from inside one.
超星系团是宇宙中最大的组织结构,并且很难定义各个星系团的边界,尤其是内部的星系。
The team used radio telescopes to map out the motions of a large collection of local galaxies.
这个研究小组使用电波望远镜在地图上标出大量局域星系团的运动。
Within a given supercluster, all galaxy motions will be directed inward, toward the center of mass.
而在超星系团内部,所有星系都是向内部质心运动。
In the case of Laniakea, this gravitational focal point is called the Great Attractor, and influences the motions of our Local Group of galaxies and all others throughout our supercluster.
至于兰天,其重力焦点被称为巨引力源并且影响着我们局域星系的运动,所有的其他星系都是穿过我们的超星系团。
It's time to update our intergalactic maps: Laniakea is home sweet home.
现在应该更新我们的星际地图:兰天就是我们的美好家园。
用英语写一篇文章介绍宇宙
研究发现仙女座星系质量几乎是银河系两倍
How heavy is the Milky Way in comparison to its neighbor galaxy, Andromeda?
和邻居仙女座相比,我们的银河系到底有多大?
Well, depends how you calculate it.
好吧,这就要看你如何计算。
In 2006 one group of astronomers figured the Milky Way was twice as massive as Andromeda.
2006年一组天文学家指出银河系的质量是仙女座的2倍。
A 2009 estimate evened the score, calculating that the two galaxies are equal in mass.
而2009年的结论则表示二者质量持平。
Now a new formula suggests we're only half the mass of Andromeda.
现在的最新结论得出我们只有仙女座星系的一半。
To come up with that number, astronomers first measured the speed and distance of galaxiesbetween three and 10 million light-years away.
这个数字是天文学家们首次根据3百万到一千万光年之间的星系的速度和距离所得出。
That allowed them to calculate the deformation of spacetime, and thus the mass, of ourstellar neighborhood, aka the Local Group—a group of more than 50 galaxies, in which theMilky Way and Andromeda dominate.
这些数据可以计算出时空弯曲的程度,从而也可得出我们邻居,一个含有50个星系以上被称为本星系群的质量大小,我们银河系和仙女座都包含在这个星系群中。
They deduced the center of mass between the two heavyweights and found that Andromedamay indeed be twice as massive as the Milky Way.
他们根据二者的重量级推导出质心,然后发现仙女座也许真的是银河系的2倍。
The results are in the Monthly Notices of the Royal Astronomical Society.
这项研究结果已在《皇家天文协会每月通告》杂志上发表。
The researchers say this new model might be more accurate than past ones, because itaccounts for dark matter far from each galaxy's center—assuming the data's right, that is.
研究人员表示这种新的模型也许比之前那些都精确,因为它是根据远离每个星系中心的暗物质计算—假设这些数据都正确,那就是正确的。
"Well, I never bet money on anything.
是的,我从来不为任何事情打赌。
Because I'm aware of all the uncertainties and approximations."
因为我会意识到所有不确定和大概的情况。
Lead author Jorge Penarrubia of the University of Edinburgh.
这项研究的首席作家爱丁堡大学的乔治佩娜拉比亚这样说道。
"One year from now, two years from now, some clever guy will come and say, ‘Hey, you forgotto include this, actually when you do everything changes,’ and then you will have to acceptthat."
从现在起的1年,2年,有些自以为聪明的家伙也许会出现:嘿,你忘记将这个算在内,实际上,当你已经开始,任何事情都在变。然后你就不得不接受。
For now, we'll just have to accept that we live in the wimpier of the two galaxies.
从现在开始,我们将不得不接受我们居住在这两个星系中的那个较小的一个上面。
At least until the next weigh-in.
至少,直到下一次有人比重前只能接受现在的结果。