關於"光"你不知道的17件事
commanded, "Let there be light," but it didn't happen for nearly half a million years. That's how long after the Big Bang the universe took to expand enough to allow photons (light particles) to travel freely.
1.神說：“要有光。”但是光直到50萬年之後纔出現——大爆炸之後50萬年，宇宙終於膨脹到足夠大，可以讓光子在其中自由穿行。
e photons are still running loose, detectable as the cosmic microwave background, a microwave glow from all parts of the sky.
2.這時光子的運動仍然是無規則的，以宇宙背景輻射的形式存在——就是從宇宙的各個部分發出的微波。
t moves along at full "light speed"—186,282.4 miles per second—only in a vacuum. In the dense matrix of a diamond, it slows to just 77,500 miles per second.
3.光只有在真空中才以“光速”，即186,282.4英里/秒（299,792,458米/秒）運動，在鑽石這樣的高密度物質中，光速會下降到77,500英里/秒（124,724,160米/秒）。
onds are the Afghanistan of gemstones: Any entering photon quickly gets bogged down. It takes a lot of pinging back and forth in a thicket of carbon atoms to find an exit. This action is what gives diamonds their dazzling sparkle.
4.鑽石是寶石中的阿富汗：任何進入其中的光子都會被迫放慢速度。光子要在錯綜複雜的碳原子間反覆衝撞才能找到出路。而這就是鑽石閃耀着令人眩目的光輝的原因。
lasses can correct vision because light changes speed when it passes from air to a glass or plastic lens; this causes the rays to bend.
5.眼鏡可以校正視力是因爲光從空氣射入玻璃或塑料的鏡片時速度會改變，於是光線就發生了彎折。
o fancied that we see by shooting light rays from our eyes.
6.柏拉圖認爲，我們之所以看得見，是因爲我們的眼睛會發射光線。
Greek philosopher was not completely wrong. Like all living things, humans are bioluminescent: We glow. We are brightest during the afternoon, around our lips and cheeks. The cause may be chemical reactions involving molecular fragments known as free radicals.
7.古希臘哲學家的看法並非完全錯誤。人類和所有其他生物一樣，都有着“生物發光現象”，也就是說人體確實會發光。我們在下午最明亮，最明亮的部位則是嘴脣和臉頰。這一現象的原因可能是名爲“自由基”的分子片段參與化學反應造成的。
uminescence is the largest source of light in the oceans; 90 percent of all creatures who live below about 1,500 feet are luminous.
8.生物發光是海洋中的最大光源：生活在距海平面1500英尺以下的生物有90%都會發光。
d War II aviators used to spot ships by the bioluminescence in their wakes.
9.二戰中的飛行員曾通過船隻尾流中的生物發光現象來定位船隻。
ndescent bulbs convert only 10 percent of the energy they draw into light, which is why Europe will outlaw them by 2012. Most of the electricity turns into unwanted heat.
10.白熾燈只能將通過自身的電能的10%轉化爲光能，而大部分電能都轉化成熱能浪費掉了。因此歐洲將在2012年禁用白熾燈。
the confined space of an Easy-Bake oven, a 100-watt bulb can create a temperature of 325 degrees Fahrenheit.
11.在一個封閉空間——比如Easy-Bake玩具烤爐裏，一個100瓦的白熾燈泡可以達到華氏325度（約163攝氏度）的高溫。
ble light makes up less than one ten-billionth of the electromagnetic spectrum, which stretches from radio waves to gamma rays.
12.在覆蓋了從無線電波到伽馬射線的電磁光譜中，可見光只佔不到百億分之一的比例。
fish can see infrared radiation that is invisible to us. Bees, birds, and lizards have eyes that pick up ultraviolet.
13.金魚可以看見我們看不見的紅外線。蜜蜂，鳥類和蜥蜴則有着可以看見紫外線的眼睛。
ography means "writing with light." English astronomer John Herschel, whose father discovered infrared, coined the term.
14.攝影其實就是“用光來書寫”。這個說法是英國宇航員John Herschel（他的父親發現了紅外線）創造的。
t now: The "golden hour," just after sunrise and before sunset, produces the prettiest shadows and colors for photographs.
15.攝影的“黃金時間”是日落後和日出前的短暫時間，此時能拍出光影和色彩都堪稱完美的照片。
ras light up the night sky when solar wind particles excite atoms in the upper atmosphere. Oxygen mostly shines green; nitrogen contributes blue and red.
16.當太陽風激發了高層大氣中的原子，就會產生極光。氧氣產生的極光多半是綠色的，氮氣則是藍色和紅色。
to the Inuits, auroras are spirits of the dead kicking around the head of a walrus.
17.但是對於居住在北極地區的因紐特人來說，極光是死者的靈魂在把海象頭當球踢……
