天文学家发现比煤炭还黑的行星
<p><span word="Astronomers">Astronomers</span> <span word="have">have</span> <span word="discovered">discovered</span> <span word="the">the</span> <span word="darkest">darkest</span> <span word="known">known</span> <span word="planet">planet</span>。</p><p><span word="The">The</span> <span word="planet">planet</span>, <span word="known">known</span> <span word="as">as</span> <span word="TrES">TrES</span>-2<span word="b">b</span>, <span word="reflects">reflects</span> <span word="less">less</span> <span word="than">than</span> 1 <span word="per">per</span> <span word="cent">cent</span> <span word="of">of</span> <span word="light">light</span>, <span word="which">which</span> <span word="makes">makes</span> <span word="it">it</span> <span word="darker">darker</span> <span word="than">than</span> <span word="any">any</span> <span word="other">other</span> <span word="planet">planet</span> <span word="or">or</span> <span word="moon">moon</span>。</p><p><span word="The">The</span> <span word="planet">planet</span>, <span word="roughly">roughly</span> <span word="the">the</span> <span word="size">size</span> <span word="of">of</span> <span word="Jupiter">Jupiter</span>, <span word="is">is</span> <span word="around">around</span> 750 <span word="light">light</span> <span word="years">years</span> <span word="away">away</span>。</p><p><span word="The">The</span> <span word="reason">reason</span> <span word="it">it</span> <span word="differs">differs</span> <span word="from">from</span> <span word="other">other</span> <span word="similar">similar</span>-<span word="sized">sized</span> <span word="planets">planets</span> <span word="is">is</span> <span word="that">that</span> <span word="Jupiter">Jupiter</span>, <span word="for">for</span> <span word="example">example</span>, <span word="is">is</span> <span word="surrounded">surrounded</span> <span word="by">by</span> <span word="ammonia">ammonia</span> <span word="clouds">clouds</span> <span word="that">that</span> <span word="reflect">reflect</span> <span word="more">more</span> <span word="than">than</span> <span word="one">one</span> <span word="third">third</span> <span word="of">of</span> <span word="its">its</span> <span word="sunlight">sunlight</span>。</p><p><span word="TrES">TrES</span>-2<span word="b">b</span> <span word="has">has</span> <span word="no">no</span> <span word="ammonia">ammonia</span> <span word="clouds">clouds</span> <span word="to">to</span> <span word="reflect">reflect</span> <span word="light">light</span> <span word="because">because</span> <span word="it">it</span> <span word="is">is</span> <span word="extremely">extremely</span> <span word="hot">hot</span>。</p><p><span word="Instead">Instead</span>, <span word="it">it</span> <span word="has">has</span> <span word="an">an</span> <span word="atmosphere">atmosphere</span> <span word="made">made</span> <span word="up">up</span> <span word="of">of</span> <span word="chemicals">chemicals</span> <span word="such">such</span> <span word="as">as</span> <span word="vaporized">vaporized</span> <span word="sodium">sodium</span>, <span word="potassium">potassium</span> <span word="and">and</span> <span word="gaseous">gaseous</span> <span word="titanium">titanium</span> <span word="oxide">oxide</span>, <span word="which">which</span> <span word="absorb">absorb</span> <span word="light">light</span>, <span word="but">but</span> <span word="that">that</span> <span word="still">still</span> <span word="does">does</span> <span word="not">not</span> <span word="explain">explain</span> <span word="the">the</span> <span word="planet">planet</span>'<span word="s">s</span> <span word="extreme">extreme</span> <span word="blackness">blackness</span>。</p><p><span word="However">However</span>, <span word="TrES">TrES</span>-2<span word="b">b</span> <span word="is">is</span> <span word="not">not</span> <span word="entirely">entirely</span> <span word="black">black</span>. <span word="Its">Its</span> <span word="extreme">extreme</span> <span word="heat">heat</span> <span word="means">means</span> <span word="it">it</span> <span word="gives">gives</span> <span word="off">off</span> <span word="a">a</span> <span word="faint">faint</span> <span word="red">red</span> <span word="glow">glow</span>。</p><p><span word="David">David</span> <span word="Kipping">Kipping</span> <span word="of">of</span> <span word="the">the</span> <span word="Harvard">Harvard</span>-<span word="Smithsonian">Smithsonian</span> <span word="Center">Center</span> <span word="for">for</span> <span word="Astrophysics">Astrophysics</span> (<span word="CfA">CfA</span>) <span word="and">and</span> <span word="his">his</span> <span word="team">team</span> <span word="arrived">arrived</span> <span word="at">at</span> <span word="the">the</span> <span word="discovery">discovery</span> <span word="by">by</span> <span word="measuring">measuring</span> <span word="the">the</span> <span word="light">light</span> <span word="TrES">TrES</span>-2<span word="b">b</span> <span word="emitted">emitted</span> <span word="as">as</span> <span word="it">it</span> <span word="orbited">orbited</span> <span word="its">its</span> <span word="star">star</span>, <span word="much">much</span> <span word="like">like</span> <span word="our">our</span> <span word="moon">moon</span> <span word="does">does</span> <span word="with">with</span> <span word="earth">earth</span>, <span word="studying">studying</span> <span word="both">both</span> <span word="the">the</span> “<span word="visible">visible</span>”<span word="side">side</span> <span word="and">and</span> <span word="its">its</span>“<span word="dark">dark</span>” <span word="side">side</span> <span word="during">during</span> <span word="orbit">orbit</span>。</p><p><span word="The">The</span> <span word="discovery">discovery</span> <span word="was">was</span> <span word="detailed">detailed</span> <span word="in">in</span> <span word="the">the</span> <span word="journal">journal</span> <span word="Monthly">Monthly</span> <span word="Notices">Notices</span> <span word="of">of</span> <span word="the">the</span> <span word="Royal">Royal</span> <span word="Astronomical">Astronomical</span> <span word="Society">Society</span>。</p><p>据英国《每日邮报》8月13日报道，天文学家发现已知最黑行星。</p><p>这颗行星被命名为<span word="TrES">TrES</span>-2<span word="b">b</span>，它仅反射低于1%的恒星光线，这使得它比迄今发现的任何行星或卫星都要暗。</p>
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