围绕太阳运行的9号行星——可能是一个黑洞

Astronomers have come up with a new theory explaining why they can't find the hypothesised 'Planet Nine' - it's not actually a planet, but a black hole.

天文学家们提出了一个新的理论来解释为什么他们找不到假设的“第九颗行星”——因为它实际上不是一颗行星，而是一个黑洞。

There's evidence of a ninth planet beyond the orbit of Neptune - scientists can see its gravitational effects on the orbits of dwarf planets like Pluto and other objects in the distant Kuiper Belt.

有证据表明，在海王星轨道之外还有第九颗行星——科学家可以看到它对冥王星等矮行星轨道的引力作用，以及柯伊伯带中其他天体的引力作用。

NASA in 2017 said it almost definitely exists, and it's likely to be about 10 times bigger than Earth - but it probably only orbits the sun every 20,000 years, and is very, very far away, so no one's actually seen it yet.

美国航天局在2017年表示，它几乎肯定存在，而且可能比地球大10倍左右——但它可能每20000年才绕太阳运行一次，而且非常非常遥远，所以还没有人真正看到它。

In a new paper however, scientists from the US and UK say there could be a good reason for that - it's a minuscule black hole that's existed since the beginning of time itself.

然而，在一篇新的论文中，来自美国和英国的科学家表示，这可能有一个很好的理由——这是一个自时间起源以来就存在的极小的黑洞。

"There is a growing body of observational anomalies connected to the orbits of trans-Neptunian Objects (TNOs)," authors Jakub Scholtz and James Unwin wrote in the new paper.

作者jakub scholtz和james unwin在新论文中写道：“越来越多的观测异常与跨海王星天体(tnos)的轨道有关。”

"These observations have been taken as evidence of a new ninth planet in our solar system, called Planet Nine."

“这些观测结果被认为是太阳系新发现的第九颗行星的证据，它被称为第九颗行星。”

But it could also be a primordial black hole, they say. Primordial black holes differ from other black holes in that they're not created in star collapses - they've existed since the first second after the Big Bang, created by gravitational perturbations in the fabric of spacetime, according to research by the late Stephen Hawking.

但他们说，它也可能是一个原始黑洞。原始黑洞不同于其他黑洞，因为它们不是在恒星崩塌中产生的——根据已故斯蒂芬霍金(stephen hawking)的研究，它们从大爆炸后的第一秒就存在了，大爆炸是由时空结构中的引力扰动造成的。

No one's ever found one, but Dr Hawking's calculations show they can be much smaller than normal black holes.

从来没有人找到过它们，但霍金博士的计算表明，它们可以比普通黑洞小得多。

"These primordial black holes can be much lighter; for example, an Earth mass, or in fact, even lighter," Dr Scholtz told Vice.

“这些原始黑洞可以更轻，比如是一个地球的质量，或者事实上，甚至更轻。”Scholtz博士告诉Vice。

If Planet Nine is actually a black hole, that would explain why no one's found it yet - not only might it be as small as a tennis ball, according to the paper, but the methods used for finding planets are different to those used to detect black holes.

如果行星9实际上是一个黑洞，这就可以解释为什么还没有人发现它——根据这篇论文，它不仅可能只有网球那么小，而且发现行星的方法与探测黑洞的方法是不同的。

"If conventional searches fail to find Planet Nine and the evidence for TNO anomalies continues to grow, the primordial black hole Planet Nine hypothesis will become a compelling explanation," the authors say.

“如果传统的搜索未能找到第九颗行星，而TNO异常的证据继续增加，那么原始黑洞第九颗行星假说将成为一个令人信服的解释。”作者说。