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By admin in 天文台 on 2019年4月7日

Scientific American 60-second Science, July 4, 2016

作者:Lee 比林s 翻译整理:SophieMen

原来的文章地址:Is Mars Missing a Moon? – Scientific
American

节奏下载:160704MartianMoons.mp3


Transript and Translation

Mars is a planet of outsized splendor. Despite being only half as
big and a tenth as heavy as Earth, it bears the solar system’s tallest
mountain, longest canyon and largest crater. At 22 and 12
kilometers wide, however, its inner moon Phobos and outer moon Deimos
are figurative small potatoes. Scientists suspect both formed much
as Earth’s single large moon did, from a massive debris disk ejected
into orbit by a giant impact eons ago. But if Mars’s moons formed like
Earth’s, why are they so very much smaller?

火星是二个具有动人光晕的星辰。尽管它的轻重唯有地球的四分之2、质量唯有地球的十一分之一,Saturn却持有太阳系最高的火山、最长的低谷和最大的火山口。Saturn的两颗卫星,内侧的Phobos和外侧的Deimos,直径分别是2二海里和1贰公里,被比喻成小土豆。物教育学家们疑惑那两颗卫星都像地球的唯1卫星月球一样,是由亿万年前在2遍伟大冲击中被射入轨道的二个大品质碎片形成的。不过只要金星的卫星的多变艺术和地球的卫星一样,为何相比而言木星的卫星小这么多呢?

The answer may be that they did not form alone. New simulations from
Pascal Rosenblatt of the Royal Observatory of Belgium and colleagues
show how the debris disk from a giant impact on Mars could have
generated additional moons a few hundreds of kilometers in size. After
forming in the dense inner regions of the disk, those larger moons would
have stirred the disk’s sparser outer reaches, allowing smaller
companions like Phobos and Deimos to coalesce from the ripples. The
study appears in the journal Nature Geoscience. [Rosenblatt et al.,
Accretion of Phobos and Deimos in an extended debris disc stirred by
transient moons]

答案可能是因为他俩并不是单身材成的。Billy时皇家天文台的Pascal罗丝nblatt和他的同事们开始展览的新仿真显示,在罗睺2回高大冲击爆发的零散形成了几百海里大小的卫星。在碎片的高密度内核形成后,这么些戴维星搅动着碎片稀疏的延伸区域,使得越来越小的如同Phobos和Deimos那样的陪伴星在涟漪中联合。那1切磋宣布在《自然·地学》期刊上[Rosenblatt
et al., Accretion of Phobos and Deimos in an extended debris disc
stirred by transient moons]。

In this scenario, the reason we only see Phobos and Deimos today is that
the bigger moons were destroyed a few million years after their
formation. Their low, fast orbits outpaced Mars’s rotation, creating a
tidal pull that sent them spiraling down to crash into the planet
(Earth’s moon, by contrast, orbited slower than our planet’s rotation,
allowing it to spiral outward and survive). Future investigations could
test the new hypothesis by looking for clusters of Martian craters
produced by the infalling moons, but in the meantime, proof that Mars
can kill its companions is right before our eyes: The orbit of Deimos is
stable, but Phobos is in a death spiral, losing two centimeters of
altitude per year to Mars’s tidal pull. It will plunge into the planet
in 20 [million] to 40 million years, leaving lonely, far-out
Deimos as the last vestige of what may have been a once-mighty system of
Martian moons.

在这场景中,大家明日只美观到Phobos和Deimos的缘故是越来越大的卫星在形成几百万年后被摧毁了。他们在又快又低的绕行中中国足球球组织一级联赛过了火星自转的快慢,形成了1种能够使他们螺旋下落坠落行星的潮汐力(相反,地球的卫星,绕行速度低于行星自转,使得卫星螺旋远离从而直接留存)。未来的探究大概由此搜Thoreau睺上由坠落卫星形成的火山口群来对那1新假若进行查看;但是还要,金星能够杀死它的伴星的凭据就在大家前边——Deimos的守则是政通人和的,不过Phobos却在离世螺旋之中,在Saturn的潮汐力成效下其惊人每年下降贰毫米。它将会在3000万年到四千万年内坠入土星,留下Deimos——作为已经长驱直入的火星卫星们的末梢遗迹——孤独而难得的存在着。


Vocabulary

  • splendor, \ˈsplen-dər, noun, 1. great and impressive
    beauty. 2. things that are very beautiful or impressive.

  • canyon, \天文台,ˈkan-yən, noun, a deep valley with steep rock sides
    and often a stream or river flowing through it.

  • crater, \ˈkrā-tər, noun, 1. a large round hole in the ground
    made by the explosion of a bomb or by something falling from the
    sky. 2. the area on top of a volcano that is shaped like a bowl

  • figurative,\ˈfi-g(y)ə-rə-tiv, adjective, 1. used with a
    meaning that is different from the basic meaning and that expresses
    an idea in an interesting way by using language that usually
    describes something else : not literal. 2.showing people and things
    in a way that resembles how they really look : not abstract.

  • debris, \də-ˈbrē, noun, 1.the pieces that are left after
    something has been destroyed. 2.things (such as broken pieces and
    old objects) that are lying where they fell or that have been left
    somewhere because they are not wanted.

  • far-out, \ˈfär-ˌau̇t, adjective, very strange or unusual.

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