關于太空，我們有太多美好的想象。事實上，太空就和電影里一樣讓人大開眼界。你知道火星的日落是藍色的嗎？你知道金星的一年比一天短嗎？你知道國際空間站有多大嗎？你知道向太空發射東西要多少錢嗎？關于外太空，我們需要了解的還有很多。商業內幕網總結的這些太空冷知識，一起來了解一下吧。

NASA has recorded eerie space "sounds."

NASA錄下詭異的“太空聲音”。

NASA uses a technique called data sonification to take signals from radio waves, plasma waves, and magnetic fields and convert them into audio tracks to "hear" what's happening in space. The sounds range from ambulance-like screeches to beeps reminiscent of an alien spaceship making its approach.

NASA利用“數據可聽化”技術，將無線電波、等離子體波、磁場的信號轉化為音軌，從而“聆聽”太空的聲音，最終聽到各式各樣的詭異聲音，如救護車警笛般的尖銳聲音、讓人聯想起外星人飛船靠近的嗶嗶聲等。

Sunsets on Mars are blue.

火星的日落是藍色的。

The Curiosity Mars rover's first color photograph of a sunset in 2015 revealed a surprising twist — sunsets on Mars are blue.

2015年，“好奇號”火星探測器拍下第一張彩色日落照，這讓人們驚訝地發現，原來，在火星上，夕陽是藍色的。

NASA said this is because "dust in the Martian atmosphere has fine particles that permit blue light to penetrate the atmosphere more efficiently than longer-wavelength colors" like yellow, orange, and red.

美國宇航局表示，這是由于火星大氣層的塵埃顆粒較小，散射藍光的能力強于長波顏色（如黃色、橙色、紅色）。


Launching things into space is wildly expensive.

向太空發射東西：貴得突破天際。

Payload specialist and space station engineer Ravi Margasahayam told Business Insider that each pound of cargo used to cost $10,000 to ship into space. Prices have skyrocketed since — Orbital Science's Cygnus spacecraft's cargo costs about $43,180 per pound, and SpaceX's new carriers about $27,000 per pound.

有效載荷專家、空間站工程師拉維·馬加薩哈雅姆告訴商業內幕網說，一磅的貨物送入太空的運費過去是1萬美元（合68335元人民幣）。但是自那以后運費就水漲船高，軌道科學公司天鵝座宇宙飛船每磅收費43180美元，而美國太空探索技術公司的新飛船是每磅2.7萬美元。

Business Insider determined that a 16-ounce bottle of water can cost anywhere between $9,100 to $43,180 to blast into space today.

據商業內幕網計算，現在將16盎司的一瓶水送入太空的運費高達9100-43180美元。

Space is full of "space junk."

太空里全是“垃圾”。

Space is full of junk like used rocket parts and dead satellites. These objects continue to orbit Earth at about 17,500 mph — 10 times as fast as a speeding bullet.

太空里全是垃圾，如報廢的火箭部件和衛星，它們繼續以約17500英里的時速繞行地球——時子彈飛行速度的10倍。

The Space Surveillance Network (SSN) keeps track of how much debris is out there. The SSN is currently tracking 23,000 objects larger than a softball.

美國空間監視網一直在追蹤太空中的垃圾數量，目前共有2.3萬件體積大于壘球的太空垃圾。

Space junk is dangerous because one collision could trigger a chain reaction of objects hitting each other, resulting in a thick cloud of debris that would make space travel extremely dangerous.

太空垃圾非常危險，因為一旦發生碰撞，可能會造成連鎖反應，由此產生的厚厚的“垃圾云”會讓太空旅行變得極為危險。

The Apollo astronauts' footprints on the moon could last up to 100 million years.

“阿波羅”宇航員在月球表面留下的腳印最多可存在1億年。

Moon rocks erode at a rate of 0.04 inches every 1 million years. This means that the astronauts' footprints on the moon from the Apollo mission in 1969 could be there for 10 to 100 million years.

月球巖石的侵蝕速率為0.04英寸（0.1厘米）/100萬年。也就是說，1969年，美國宇航員執行阿波羅任務時在月球表面留下的腳印能夠存在1千萬到1億年。

Space isn't always cold. In fact, it can get pretty hot.

太空不總是冰冷的，它也可以很炎熱。

In the darkest parts of space, temperatures can reach -454 degrees Fahrenheit. But if you're orbiting near Earth in the sunlight, space is a toasty 250 degrees Fahrenheit. Astronauts' spacesuits are white to reflect the heat they encounter while floating above the Earth.

在太空最陰暗的地帶，溫度可達零下270攝氏度（零下454華氏度）；但若處于地球附近的陽光里，溫度可達滾燙的120攝氏度。宇航員的太空服是白色的，在他們漂浮在地球上方時白色服裝可以反射光熱。

A year on Venus is shorter than a day there.

金星的一年比一天短。

Venus spins very slowly in the opposite direction of Earth — 243 Earth days for a full rotation. But it only takes 225 days to go around the sun because it's so close to it. Therefore, a year on Venus is shorter than a day.

金星自轉速度很慢，而且和地球自轉方向相反。金星繞太陽公轉一周僅需225個地球日，因為金星離太陽很近，但金星自轉一周卻需要243個地球日。因此，金星的一年比一天短。

The International Space Station (ISS) is the size of a football field.

國際空間站和美式橄欖球場差不多大。

The International Space Station is 357 feet long, just three feet less than an American football field. It weighs 925,000 pounds and is the largest single human-made structure to ever enter space.

國際空間站長109米，只比美式橄欖球場少0.9米，重84萬千克，是太空中迄今為止最大的人造建筑物。

The ISS has been visited by 230 people from 18 different countries to conduct research and carry out missions.

迄今為止，曾有來自18個國家的230人造訪過國際空間站，開展研究和執行任務。

You would last about 15 seconds in space without a spacesuit.

若沒有太空服，你能在太空中堅持15秒左右。

Because there's no pressure in space, air expands. This means the air inside your lungs would expand and tear through the tissue. And in such an extreme environment, your body would use up all of the oxygen in your blood in about 15 seconds. Other gruesome consequences of unprotected space exposure would include loss of bowel control, boiling blood, exploding capillaries, and bloating.

由于太空中沒有壓力，肺部空氣會膨脹并撕裂組織。在這種極端環境中，身體會在15秒內耗光血液中的氧氣。此外，還會出現種種可怕狀況：大便失禁、血液沸騰、毛細血管爆裂、腫脹……

Outer space isn't empty space.

太空并非完全真空。

Besides the obvious stars and planets, you might think that the surrounding space is completely empty — a perfect vacuum devoid of all matter.

你或許認為，除了恒星、行星等天體外，太空就是不存在任何物質的真空。

It's true that space is a vacuum, but it's an imperfect vacuum because it contains a low density of particles like clouds of interstellar dust, space plasma, and cosmic rays.

沒錯，太空是真空的，但它并非完全真空。它還含有星際塵埃云、空間等離子體、宇宙射線等低密度物質。

英文來源：商業內幕網

翻譯&編輯：丹妮