关于“光” 你不知道的17件事
<p>1.<span word="God">God</span> <span word="commanded">commanded</span>, “<span word="Let">Let</span> <span word="there">there</span> <span word="be">be</span> <span word="light">light</span>,” <span word="but">but</span> <span word="it">it</span> <span word="didn">didn</span>’<span word="t">t</span> <span word="happen">happen</span> <span word="for">for</span> <span word="nearly">nearly</span> <span word="half">half</span> <span word="a">a</span> <span word="million">million</span> <span word="years">years</span>. <span word="That">That</span>’<span word="s">s</span> <span word="how">how</span> <span word="long">long</span> <span word="after">after</span> <span word="the">the</span> <span word="Big">Big</span> <span word="Bang">Bang</span> <span word="the">the</span> <span word="universe">universe</span> <span word="took">took</span> <span word="to">to</span> <span word="expand">expand</span> <span word="enough">enough</span> <span word="to">to</span> <span word="allow">allow</span> <span word="photons">photons</span> (<span word="light">light</span> <span word="particles">particles</span>) <span word="to">to</span> <span word="travel">travel</span> <span word="freely">freely</span>.</p><p>神说：“要有光。”但是光直到50万年之后才出现——大爆炸之后50万年，宇宙终于膨胀到足够大，可以让光子在其中自由穿行。</p><p>2.<span word="Those">Those</span> <span word="photons">photons</span> <span word="are">are</span> <span word="still">still</span> <span word="running">running</span> <span word="loose">loose</span>, <span word="detectable">detectable</span> <span word="as">as</span> <span word="the">the</span> <span word="cosmic">cosmic</span> <span word="microwave">microwave</span> <span word="background">background</span>, <span word="a">a</span> <span word="microwave">microwave</span> <span word="glow">glow</span> <span word="from">from</span> <span word="all">all</span> <span word="parts">parts</span> <span word="of">of</span> <span word="the">the</span> <span word="sky">sky</span>.</p><p>这时光子的运动仍然是无规则的，以宇宙背景辐射的形式存在——就是从宇宙的各个部分发出的微波。</p><p>3.<span word="Light">Light</span> <span word="moves">moves</span> <span word="along">along</span> <span word="at">at</span> <span word="full">full</span> “<span word="light">light</span> <span word="speed">speed</span>”—186,282.4 <span word="miles">miles</span> <span word="per">per</span> <span word="second">second</span>—<span word="only">only</span> <span word="in">in</span> <span word="a">a</span> <span word="vacuum">vacuum</span>. <span word="In">In</span> <span word="the">the</span> <span word="dense">dense</span> <span word="matrix">matrix</span> <span word="of">of</span> <span word="a">a</span> <span word="diamond">diamond</span>, <span word="it">it</span> <span word="slows">slows</span> <span word="to">to</span> <span word="just">just</span> 77,500 <span word="miles">miles</span> <span word="per">per</span> <span word="second">second</span>.</p><p>光只有在真空中才以“光速”，即186,282.4英里/秒（299,792,458米/秒）运动，在钻石这样的高密度物质中，光速会下降到77,500英里/秒（124,724,160米/秒）。</p><p>4.<span word="Diamonds">Diamonds</span> <span word="are">are</span> <span word="the">the</span> <span word="Afghan">Afghan</span><span word="istan">istan</span> <span word="of">of</span> <span word="gemstones">gemstones</span>: <span word="Any">Any</span> <span word="entering">entering</span> <span word="photon">photon</span> <span word="quickly">quickly</span> <span word="gets">gets</span> <span word="bogged">bogged</span> <span word="down">down</span>. <span word="It">It</span> <span word="takes">takes</span> <span word="a">a</span> <span word="lot">lot</span> <span word="of">of</span> <span word="pinging">pinging</span> <span word="back">back</span> <span word="and">and</span> <span word="forth">forth</span> <span word="in">in</span> <span word="a">a</span> <span word="thicket">thicket</span> <span word="of">of</span> <span word="carbon">carbon</span> <span word="atoms">atoms</span> <span word="to">to</span> <span word="find">find</span> <span word="an">an</span> <span word="exit">exit</span>. <span word="This">This</span> <span word="action">action</span> <span word="is">is</span> <span word="what">what</span> <span word="gives">gives</span> <span word="diamonds">diamonds</span> <span word="their">their</span> <span word="dazzling">dazzling</span> <span word="sparkle">sparkle</span>.</p><p>钻石是宝石中的阿富汗：任何进入其中的光子都会被迫放慢速度。光子要在错综复杂的碳原子间反复冲撞才能找到出路。而这就是钻石闪耀着令人眩目的光辉的原因。</p>
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