劍橋雅思9Test2閱讀Passage2原文翻譯 venus in transit

劍橋雅思9 Test2 Passage1閱讀原文翻譯

引言

June 2004 saw the first passage, known as a ‘transit’, of the planet Venus across the face of the Sun in 122 years. Transits have helped shape our view of the whole Universe, as Healther Cooper and Nigel Henbest explain

2004年6月，金星122年來首次穿過太陽面，稱為“凌日”。正如Healther Cooper和Nigel Henbest 解釋的那樣，凌日幫助塑造我們對整個宇宙的看法.

自然段A

On 8 June 2004, more than half the population of the world were treated to a rare astronomical event. For over six hours, the planet Venus steadily inched its way over the surface of the Sun. This ‘transit’ of Venus was the first since 6 December 1882. On that occasion, the American astronomer Professor Simon Newcomb led a party to South Africa to observe the event. They were based at a girl’s school, where—it is alleged—the combined forces of three schoolmistresses outperformed the professionals with the accuracy of their observations.

2004年6月8日，全世界一半以上的人口都可以觀測到一起罕見的天文事件。在六個多小時的時間里，金星穩(wěn)步向太陽表面前進。這次金星的“凌日”是自1882年12月6日以來的第一次。當時，美國天文學家西蒙·紐科姆教授率領(lǐng)團體前往南非觀察這一事件。他們將觀察點設(shè)在一所女子學校，據(jù)稱，三名女教師的聯(lián)合隊伍在觀察的準確性方面勝過專業(yè)人士。

自然段B

For centuries, transits of Venus have drawn explores and astronomers alike to the four corners of the globe. And you can put it all down to the extraordinary polymath Edmond Halley. In November 1677, Halley observed a transit of the innermost planet, Mercury, from the desolate island of St Helena in the south Pacific. He realized that, from different latitudes, the passage of the planet across the Sun’s disc would appear to differ. By timing the transit from two widely-separated locations, teams of astronomers could calculate the parallax angle—the apparent difference in position of an astronomical body due to a difference in the observer’s position. Calculating this angle would allow astronomers to measure what was then the ultimate goal: the distance of the Earth from the sun. This distance is known as the ‘a(chǎn)stronomical’ or AU.

幾個世紀以來，金星凌日吸引著探險家和天文學家來到地球的各個角落。你可以將其歸因于非凡的博學大師埃德蒙·哈雷（Edmond Halley）。1677年11月，哈雷從南太平洋荒涼的圣赫勒拿島觀察到太陽系最里面的行星-水星凌日。他意識到，從不同的緯度來看，行星穿過太陽的路徑似乎有所不同。通過從兩個相距較遠的位置記錄穿行的時間，天文學家團隊可以計算視差角-由于觀測者位置的差異所造成的天體位置的明顯差異。計算該角度將使天文學家能夠測量出當時的終極目標：地球與與太陽之間的距離。該距離稱為“天文單位”或AU。

自然段C

Halley was aware that the AU was one of the most fundamental of all astronomical measurements. Johannes Kepler, in the early 17th century, had shown that the distances of the planets from the Sun governed their orbital speeds, which were easily measurable. But no-one had found a way to calculate accurate distances to the planets from the earth. The goal was to measure the AU; then, knowing the orbital speeds of all the other planets round the Sun, the scale of the Solar System would fall into place. However, Halley realized that Mercury was so far away that its parallax angle would be very difficult to determine. As Venus was closer to the Earth, its parallax angle would be larger, and Halley worked out that by using Venus it would be possible to measure the Sun’s distance to 1 part in 500. But there was a problem: transits of Venus, unlike those of Mercury, are rare, occurring in pairs roughly eight years apart every hundred or so years. Nevertheless, he accurately predicted that Venus would cross the face of the Sun in both 1761 and 1769—though he didn’t survive to see either.

哈雷意識到，AU是所有天文測量中最基本的一項。開普勒在17世紀初已經(jīng)證明，行星距太陽的距離決定著它們的軌道速度，這是容易衡量的。但是，沒有人找到一種計算其他行星距地球精確距離的方法。其目的就是為了測量AU。在知道所有其他行星繞太陽運行的軌道速度后，太陽系的規(guī)模就會明確起來。但是，哈雷意識到水星距離太遠，以至于很難確定其視角差。由于金星離地球更近，其視差角會更大。哈雷由此得出結(jié)論，通過利用金星，可以將太陽距離的測量誤差縮小到1/500。但是與水星不同，金星凌日的現(xiàn)象很少見，每100多年會成對出現(xiàn)兩次，這兩次之間相隔8年。雖然他準確地預(yù)測到金星將在1761年和1769年穿過太陽表面，但他并沒有活著見到任何一次。

自然段D

Inspired by Halley’s suggestion of a way to pin down the scale of the Solar System, teams of British and French astronomers set out on expeditions to places as diverse as India and Siberia. But things weren’t helped by Britain and France being at war. The person who deserves most sympathy is the French astronomer Guillaume Le Gentil. He was thwarted by the fact that the British were besieging his observation site at Pondicherry in India. Feeling on a French warship crossing the Indian Ocean, Le Gentil saw a wonderful transit—but the ship’s pitching and rolling ruled out any attempt at making accurate observations. Undaunted, he remained south of the equator, keeping himself busy by studying the islands of Mauritius and Madagascar before setting off to observe the next transit in the Philippines. Ironically after travelling nearly 50,000 kilometres, his view was clouded out at the last moment, a very dispiriting experience.

受哈雷關(guān)于確定太陽系規(guī)模的建議的啟發(fā)，英國和法國的天文學家團隊開始對各種地方（包括印度和西伯利亞）進行考察。但是，英國和法國的交戰(zhàn)幫了倒忙。最值得同情的人是法國天文學家Guillaume Le Gentil 。英國人包圍了他在印度Pondicherry的觀察站，使他受挫。乘坐法國軍艦穿越印度洋時，Le Gentil觀測到了一次完美的凌日。但船的起伏和搖晃使得進行準確觀測的嘗試化為泡影。他沒有因此而退縮，一直待在赤道以南，忙著研究毛里求斯和馬達加斯加的島嶼，然后出發(fā)去菲律賓觀測下一次凌日。具有諷刺意味的是，在行駛了將近50,000公里之后，他的視線在最后一刻被云層遮擋，這是非常令人沮喪的經(jīng)歷。

自然段E

While the early transit timings were as precise as instruments would allow, the measurements were dogged by the ‘black drop’ effect. When Venus begins to cross the Sun’s disc, it looks smeared not circular—which makes it difficult to establish timings. This is due to diffraction of light. The second problem is that Venus exhibits a halo of light when it is seen just outside the Sun’s disc. While this showed astronomers that Venus was surrounded by a thick layer of gases refracting sunlight around it, both effects made it impossible to obtain accurate timings.

盡管早期對凌日時間的觀測已經(jīng)達到儀器所允許的上限，但測量卻受到“黑點”效應(yīng)的困擾。當金星開始越過太陽表面時，它看起來有點模糊，而不完全是圓的，使確定時間變得困難。這種現(xiàn)象是由于光的衍射。第二個問題是金星在躍出太陽表面時會出現(xiàn)光暈。盡管這向天文學家表明，金星被厚厚的氣體層所包圍。它會折射周圍的陽光，但這兩種現(xiàn)象都使得無法獲得準確的時間。

自然段F

But astronomers laboured hard to analyse the results of these expeditions to observe Venus transits. John Franz Encke, Director of the Berlin Observatory, finally determined a value for the AU based on all these parallax measurements: 153,340,000km. Reasonably accurate for the time, that is quite close to today’s value of methods in accuracy. The AU is a cosmic measuring rod, and the basis of how we scale the Universe today. The parallax principle can be extended to measure the distances to the stars. If we look at a star in January—when Earth is at one point in its orbit—it will seem to be in a different position from where it appears six months later. Knowing the width of Earth’s orbit, the parallax shift lets astronomers calculate the distance.

但是天文學家們辛苦地分析了這些探險的結(jié)果，以觀察金星凌日的現(xiàn)象。柏林天文臺局長John Franz Encke 最終根據(jù)所有這些視差測量值確定了AU的數(shù)字：153,340,000 km。對于當時來說，這個數(shù)字已經(jīng)足夠準確，與當今雷達測量的數(shù)值（149,597,879km）十分接近。而雷達因其精準度已經(jīng)取代了凌日觀測和其他方法。AU是宇宙測量標桿，也是我們今天確定宇宙規(guī)模的基礎(chǔ)。視差原理可以擴展到測量地球到恒星的距離。如果我們在一月份觀測一顆恒星（當?shù)厍蛟谄滠壍郎咸幱谀骋稽c時），其位置似乎與六個月后看到的位置不同。知道了地球軌道的寬度，視覺差可以讓天文學家計算其距離。

自然段G

June 2004’s transit of Venus was thus more of an astronomical spectacle than a scientifically important event. But such transits have paved the way for what might prove to be one of the most vital breakthroughs in the cosmos—detecting Earth-sized planets orbiting other stars.

因此，2004年6月金星凌日更像是一場天文奇觀，而不是科學上重要的事件。但是，這種凌日為可能是宇宙中最重要的突破之一-探測繞著其他恒星運行的類地行星- 鋪平了道路。

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