涅墨西斯

它曾被当做行星命名为堤喀或者简单的X行星。或者曾被当作一颗恒星命名为涅墨西斯星。

As a planet , it 's been called Tyche or simply Planet X. As a star , Nemesis .

这一研究发现对某些理论是个不小的冲击，比如X行星或涅墨西斯星之类的天体曾造成地球上的物种灭绝。

The finding deals a blow to theories that a Planet X - or Nemesis-type object may have caused periodic mass extinctions on Earth .

该理论认为涅墨西斯星球每隔2700万年会穿过奥尔特云向地球发射一大批彗星。

The theory was that Nemesis crashed through the Oort cloud every 27 million years and sent a shower of comets in our direction .

20世纪80年代时科学家们认为地球周期性的生物灭绝可能是由遥远太空的涅墨西斯星球造成的，该星球和太阳很相似。

In the 1980s scientists believed that Earth 's regular extinctions could be the result of a distant dark twin of the Sun , called Nemesis .

然而现在科学家称大灭绝的周期性实际上证明涅墨西斯星球理论是错误的，因为随着时间的推移，在和其他星球的相互作用下，星球的运行轨迹会发生改变。

But now scientists claim that the regularity of the mass extinctions actually disproves the Nemesis theory because its orbit would have changed over time as it interacted with other stars .