大學(xué)物理實驗分光計實驗報告(獨家編譯)

今年，天體物理學(xué)家們在多個方面取得了開創(chuàng)性成果。從在海上回收火箭，到發(fā)現(xiàn)宇宙中最極端事件，引力波，2016年科學(xué)領(lǐng)域的成就非同凡響。

以下內(nèi)容就是本年度空間探索的亮點。

1.引力波

今年，最令人震撼的公告就是科學(xué)家們搜尋到了一陣時空的漣漪（在兩個黑洞合并成型的時刻），這在科學(xué)界引起了巨大的波瀾。利用“激光干涉引力波觀測站”（LIGO）科學(xué)家們發(fā)現(xiàn)了引力波，這就像是用全新的眼睛去看宇宙。

引力波導(dǎo)致LIGO探測器的一條臂長變長的同時另一條臂長變短，能檢測出引力波所引起的小于原子中心中質(zhì)子直徑千分之一尺度的變化量。相對來說，這就像測量距離最近的一顆恒星上，一根頭發(fā)寬度的變化。

這一發(fā)現(xiàn)是歷經(jīng)一個世紀的探索，證實愛因斯坦最后的預(yù)測，引力波是真實存在的。它也讓我們能夠直接“看到”，之前看不到的對象：黑洞（并證實它的存在）。兩個黑洞在13億年前碰撞，引力波經(jīng)過漫長的旅行，剛剛抵達了地球，就被LIGO探測到，這都為本次發(fā)現(xiàn)增添了神秘的色彩。

2. SpaceX完成首次海上火箭回收

SpaceX今年就有一個很不錯的開端，把一顆衛(wèi)星送入預(yù)定軌道，以這么低的成本發(fā)射火箭本身就是壯舉了，他們還把火箭在海上回收了。這意味著火箭發(fā)射、著陸的單向過程，進入了低成本，可重復(fù)利用火箭的新階段。

不幸的是，由于獵鷹9號在發(fā)射臺爆炸，該公司宣布停止火箭發(fā)射，但是，有望在1月初重新啟動。

艾倫?馬斯克的遠景規(guī)劃是，建立一個火星城市，盡管這存在很多挑戰(zhàn)，2016年對于SpaceX是大起大落的一年。

3.最近的恒星可能存在與地球類似的世界

比鄰星是太陽最近的鄰居，只有4光年的距離，它的太陽系里可能包含一個與地球類似的世界。直到今年，天文學(xué)家還沒有確定，是否有行星圍繞這顆恒星運轉(zhuǎn)，更不用說找到我們有生之年可以拜訪的、太陽系以外生命的港灣了。

倫敦瑪麗皇后大學(xué)的研究團隊發(fā)現(xiàn)了這顆行星，將其命名為"Proxima b"。利用比鄰星的光，天文學(xué)家能夠探測到恒星軌道的微妙變化（視為一個“擺動”），這是說明附近存在另一個巨大的天體。

但是比鄰星的大小僅是太陽的10%，Proxima b的軌道周期也只有11天，這意味著它非?？拷阈?，就在所謂的宜居帶上。后續(xù)無論是哈勃或是即將上任的詹姆斯 韋伯太空望遠鏡用來跟蹤確定這顆行星上是否像地球一樣適合生命，都是十分必要的。

4. 突破性的聆聽計劃和Starshot計劃啟動

Proxima b可能是地球的一個雙胞胎，現(xiàn)在最大的挑戰(zhàn)是如何在我們有生之年到達這里。突破性的計劃starshot得到了俄羅斯億萬富翁尤里?米爾納的資助和史蒂芬?霍金的贊同，nanosails可以被光束推進達到數(shù)百萬公里每小時的速度。

這樣的速度能夠讓宇宙飛船花20年左右的時間到達Proxima b，從而使人類首次向另一個已知行星發(fā)送信息。

但是目前還存在許多挑戰(zhàn)，如這樣的技術(shù)還不存在，與星際之間氣體與塵埃的高速碰撞可能會在它達到目的地之前就被摧毀。

人類非常聰明，關(guān)鍵技術(shù)正以指數(shù)級的速度推進。到另一個星球旅行不再是科幻小說，而是一個雄心勃勃的科學(xué)項目。

也許，外星人已經(jīng)以無線電傳輸?shù)男问桨l(fā)出了他們自己的信息。另一個突破性的計劃是聆聽計劃，也是由霍金倡導(dǎo)的，天文學(xué)家們正在距離我們最近的上百萬顆恒星附近，尋找宜居帶，來探測可能出現(xiàn)的無線電信號。包括澳大利亞自己的帕克斯射電望遠鏡（以及探測可見光的綠岸望遠鏡和利克天文臺），整個2016年都在進行觀測，搜索外星信號的任務(wù)將在未來十年持續(xù)進行。

5. 菲萊和羅塞塔團聚

2014年，菲萊成為首個登陸彗星的太空探測器，雖然它的著陸過程不順利，導(dǎo)致數(shù)據(jù)傳輸中斷。但最近它被羅塞塔發(fā)現(xiàn)，使得它能夠繼續(xù)進行彗星67P的分析工作。

菲萊登陸的地點及探測的方位，能夠讓天文學(xué)家們準確解釋羅塞塔獲取的，關(guān)于彗星組成的數(shù)據(jù)。

菲萊已經(jīng)在巖石縫隙中生活了兩年，羅塞塔一直在忙碌，拍攝了大量的圖片，以及彗星的光譜和其它數(shù)據(jù)、

實際上，對羅塞塔分光計獲取的數(shù)據(jù)進行分析，發(fā)現(xiàn)彗星揮發(fā)的成分中包含氨基酸、甘氨酸，由于日照加熱變得不穩(wěn)定，它們脫離彗星表面。甘氨酸是構(gòu)成生命的基本組成；對于蛋白質(zhì)和DNA都是必需的，這些已經(jīng)確定的地球大氣圈外的物質(zhì)，對地球上的生命來說獨一無二的，我們感謝彗星為我們微生物祖先提供了這些關(guān)鍵成分。

前景展望

2017年對于澳大利亞的天體物理學(xué)家來說，前景十分光明，卓越中心的：CAASTRO-3-D 研究宇宙時原子的構(gòu)建；OzGRav利用引力波探索宇宙；以及SABRE，世界上第一個位于南半球的暗物質(zhì)探測器，年底安裝。

如果你認為2016是空間研究偉大的一年，那么請期待2017的精彩。（張微編譯）

以下為英文原文：

2016—the year in space and astronomy

The achievements of astrophysicists this year were as groundbreaking as they were varied. From reuniting a lander with a mothership on a comet, to seeing the most extreme cosmic events with gravitational waves, 2016 was truly out of this world for science.

Here are some of the highlights of the year that was.

1. Gravitational Waves

The spectacular announcement that ripples in the very fabric of spacetime itself had been found (and from surprisingly massive black holes colliding) sent similarly massive ripples through the scientific community. The discovery was made using the Laser Interferometer Gravitational-Wave Observatory (LIGO) and represents a fundamentally new sense with which to see the universe.

The gravitational waves cause one arm of the LIGO detector to stretch relative to the other by less than a thousandth of the width of a proton in the centre of the atom. Relatively speaking, that's like measuring a hair's-width change in the distance to the nearest star.

This discovery was the end of a century-long quest to prove Einstein's final prediction that these gravitational waves are real. It also allows us to directly "see" that famously and fundamentally invisible entity: the black hole (as well as definitively proving its existence). The fact that the two black holes collided 1.3 billion years ago and the waves swept through Earth just days after turning the detector on only add to the incredible story of this discovery.

2. SpaceX lands (and crashes) a rocket

The year started so well for SpaceX with the incredible achievement of sending a satellite into orbit, which is no mean feat itself at such low cost, before then landing that launch rocket on a barge in the ocean. A seemingly unstoppable sequence of launches and landings made it appear that a new era of vastly cheaper access to space through rockets that could be refuelled and reused was at hand.

Unfortunately, with the explosion of a Falcon 9 on the launchpad, the company was grounded, but apparently hopes for a resumed launch in early January.

Add to that the visionary plans to settle Mars outlined by Elon Musk, albeit not without some audacious challenges, and it's been a year of highs and lows for SpaceX.

3. Closest star may harbour Earth-like world

Proxima Centauri is our Sun's nearest neighbour at just over four light years away, and it appears that its solar system may contain an Earth-like world. Until this year, astronomers weren't even sure that any planets orbited the star, let alone ones that might harbour the best extrasolar candidate for life that spacecraft could visit within our lifetime.

The planet, creatively named "Proxima b", was discovered by a team of astronomers at Queen Mary University in London. Using the light of Proxima Centuari, the astronomers were able to detect subtle shifts in the star's orbit (seen as a "wobble"), which is the telltale sign that another massive object is nearby.

While Proxima Centuari is barely 10% the size of our Sun, Proxima b's orbit is only 11 days long, meaning it is very close to the star and lies just within the so-called habitable zone. However, follow-up with either Hubble or the upcoming James Webb Space telescope is necessary to determine if the exoplanet is as well suited for life as Earth.

4. Breakthrough Listen listening and Starshot star-ted

With a potential Earth twin identified in Proxima b, now the challenge is to reach it within a human lifetime. With the breakthrough initiative starshot, which has been funded by Russian billionaire Yuri Milner and endorsed by none other than Stephen Hawking, lightweight nanosails can be propelled by light beams to reach speeds up to millions of kilometres an hour.

Such speeds would allow a spacecraft to arrive at Proxima b in about 20 years, thus enabling humans to send information to another known planet for the first time.

However, there are many challenges ahead, such as the fact that the technology doesn't exist yet, and that high-speed collisions with gas and dust between stars may destroy it before it can reach its target.

But humans have proven to be resourceful, and key technology is advancing at an exponential rate. Incredibly the idea of sailing to another world is no longer science fiction, but rather an outrageously ambitious science project.

Perhaps, aliens are already sending out their own information in the form of radio transmissions. In another breakthrough initiative called Listen, also championed by Hawking, astronomers will be searching the habitable zones around the million closest stars to try to detect incoming radio transmissions. Involving Australia's very own Parkes telescope (as well as the Green Bank Telescope and Lick Observatory at visible wavelengths of light), observations have been running through 2016 and the search for alien signals will continue for the next decade.

5. Philae reunited with Rosetta

In 2014 the Philae lander became the first space probe to land on a comet, and even though its crash landing dictated that its science transmission would be a one-off, its recent rediscovery by Rosetta has allowed it to continue to contribute to analysis of comet 67P.

Philae's crash location, as well as the orientation of the doomed probe, has allowed astronomers to accurately interpret data taken by Rosetta regarding the composition of the comet.

While Philae has literally been living under (crashed on) a rock for the past two years, Rosetta has been the busy bee, taking numerous images, spectroscopy and other data of the comet.

In fact, data taken from Rosetta's spectrometer has been analysed and revealed that the amino acid, glycine, is present in the comet's outgassing, which breaks away from the surface of the comet as it becomes unstable from solar heating. Glycine is one of the fundamental building blocks of life; necessary for proteins and DNA, and its confirmed extraterrestrial confirms that the ingredients for life are unique to Earth, and that we may have comets to thank for providing our microbial ancestors with those crucial ingredients.

Outlook for Down Under

The future for astrophysics in Australia in 2017 looks particularly bright, with two ARC Centres of Excellence:CAASTRO-3-D studying the build of atoms over cosmic time; and OzGRav exploring the universe with gravitational waves; as well as SABRE, the world's first dark matter detector in the Southern Hemisphere, installed by end of the year.

If you thought 2016 was a great year in space, then you're in for a treat in 2017.