科學美國人60秒英文文本：
This is Scientific American 60 Secomds, Space. I'm Clara Moskowitz, got a minute?
Solar system conspiracy theorists have long harbored suspicions that a hidden extra planet or dwarf star lies beyond the orbit of Pluto. As a planet, it’s been called Tyche or simply Planet X. As a star, Nemesis.
But an exhaustive search has found no hints of this long-rumored object. NASA's Wide-Field Infrared Survey Explorer has scanned the entire sky in infrared light—twice—and ruled out any hidden bodies larger than Saturn out to 10,000 times the distance from the Earth to the sun.
Furthermore, it found no evidence for anything bigger than Jupiter out to 26,000 times the Earth-sun distance. Pluto, for comparison, lies only 40 times farther from the sun than Earth.
The finding deals a blow to theories that a Planet X- or Nemesis-type object may have caused periodic mass extinctions on Earth. Some theorists have mused that a hidden planet might have swept through bands of comets in the solar system, sending them crashing into Earth. Now it seems that for such mass species die-offs, the fault lies not in the stars.
Thanks for the minute for Scientific American 60 Secomds, Tech. I'm Clara Moskowitz.
這裏是科學美國人60秒，太空系列。我是克拉拉·莫斯科維茲。
太陽系陰謀論者一直以來長期庇護這樣一個觀點，那就是在冥王星軌道深處還隱藏着一顆行星或是矮星。它曾被當做行星命名爲堤喀或者簡單的X行星。或者曾被當作一顆恆星命名爲涅墨西斯星。
但是一個詳細的調查已經發現這顆長期被傳聞籠罩物體的.真實面目。NASA的廣譜紅外調查探測設備已經第二次用紅外線掃描出這顆星球的全部大氣層,排除了任何可能比土星大，距離地球到太陽一萬倍的任何隱藏物體。
此外，還發現沒有比木星更大的，超過日地距離26000倍的任何可能存在物體。而冥王星比地球距太陽的間距只遠40倍。這一研究發現對某些理論是個不小的衝擊，比如X行星或涅墨西斯星之類的天體曾造成地球上的物種滅絕。
這一研究發現對某些理論是個不小的衝擊，比如X行星或涅墨西斯星之類的天體曾造成地球上的物種滅絕。一些理論家已經考慮一顆隱藏的行星也許本該被太陽系存在的一個彗星帶打掃乾淨，而且轉而衝向地球。現在按照如此這般推論看來，大規模物種滅絕其實的罪魁禍首並不是這些行星。
