False “stars” could disorient wildlife

Christie Wilcox

SpaceX, a US aerospace company, plans to transform global Internet access with its multi‐satellite Starlink program, but astronomers have voiced concerns about how such “satellite mega‐constellations” will transform the night sky itself. Because the satellites will appear extremely bright due to their low orbit, it is feared they will interfere with ground‐based telescopes and obstruct the view of the cosmos (Astron Astrophys 2020; doi.org/​10.1051/​0004-6361/20203​7501).

But humans are not the only animals that look to the stars. Numerous creatures rely on celestial navigation, but the effect that low‐Earth‐orbiting artificial satellites may have on them has yet to receive dedicated scientific scrutiny, according to sensory ecologist James Foster (University of Würzburg; Würzburg, Germany). So, he was pleased to see this topic appear in Trends in Ecology and Evolution’s Horizon Scan of Emerging Global Biological Conservation Issues for 2021 (2021; doi.org/10.1016/j.tree.2020.​10.014).

“Artificial objects introduced into an animal’s visual environment affect them just like those introduced into their immediate environment”, explains Foster. Studies have shown that ground‐based light pollution can harm nocturnal animals, and low‐orbit satellites could exacerbate such risks by brightening the night sky even further. Foster and his colleagues have also found that increased skyglow can obscure the visual patterns that animals use to orient themselves, “to the point”, says Foster, “where they can no longer hold a straight course”. In addition to generally brightening the night sky, by acting as fake “stars” that move in unexpected ways, these satellites could also interfere with the pattern‐based “star compasses” that many migratory birds and other animals, such as dung beetles, rely on for orientation (P Roy Soc B‐Biol Sci 2018; doi.org/10.1098/rspb.2017.2322).

How much of an issue this will actually be remains to be determined, however. Nocturnal animals already cope with wide fluctuations in sky brightness from lunar phases, and planets may also be potentially unanticipated bright moving spots. “For low‐orbit satellites to substantially alter night‐sky brightness or change the apparent pattern of stars enough for a star compass to fail, there would really need to be a lot of them”, Foster points out, adding that species most susceptible to such impacts are already faced with the more substantial and immediate threats posed by the rapid spread of ground‐based nighttime light pollution.

As it happens, humans may be most affected by these artificial twinkling lights, and Foster empathizes with those troubled by the planned installations. “A pristine night sky is a beautiful thing, and it would be a shame to lose it due to human interference.”

Starlink satellites crossing the sky over southern Brazil.

E Filter; CC BY 4.0

中文翻译：

---

派遣

虚假的“星星”可能会使野生动植物迷惑

克里斯蒂·威尔科克斯（Christie Wilcox）

美国航空航天公司SpaceX计划通过其多卫星Starlink计划改变全球互联网访问，但是天文学家对这种“卫星巨型星座”将如何改变夜空本身表示担忧。由于卫星由于其低轨道而显得异常明亮，因此担心它们会干扰地面望远镜并阻碍宇宙视线（Astron Astrophys 2020; doi.org/ 10.1051 / 0004-6361 / 20203 7501）。

但是，人类并不是唯一仰望星空的动物。感官生态学家詹姆士·福斯特（James Foster）（维尔茨堡大学；德国维尔茨堡）表示，许多生物都依赖天体导航，但低轨道人造卫星可能对它们产生的影响尚未受到专门的科学审查。因此，他很高兴看到这个话题出现在《生态与进化趋势》的《展望2021年全球新兴生物保护问题》（2021; doi.org/10.1016/j.tree.2020.10.014）中。

Foster解释说：“引入动物视觉环境的人造物体对动物的影响就像引入其直接环境的那些动物一样。” 研究表明，地面光污染会损害夜间活动的动物，低轨道卫星可能会进一步使夜空变亮，从而加剧这种风险。福斯特和他的同事们还发现，不断增加的天花可以掩盖动物用来定向自己的视觉模式，“直截了当”，福斯特说，“它们不再能够保持平直的路线了”。这些人造卫星除了可以照亮夜空外，还可以充当以意外方式移动的假“星”，还可以干扰许多候鸟和其他动物（例如ung虫）所依赖的基于模式的“星罗盘”开启方向（P Roy Soc B‐Biol Sci 2018; doi.org/10.1098/rspb.2017.2322）。

但是，实际上到底有多少个问题尚待确定。夜行性动物已经可以应付月相期间天空亮度的大幅波动，行星也可能是意料之外的亮动点。福斯特指出：“要使低轨道卫星充分改变夜空的亮度或改变恒星的表观格局，足以使星罗盘失效，确实需要有很多这样的卫星。”他补充说，最容易受到干扰的物种这种影响已经面临着地面夜间光污染迅速蔓延带来的更为严重和直接的威胁。

碰巧的是，人类可能会受到这些人造闪烁灯的最大影响，而福斯特对那些受到计划安装的麻烦困扰的人表示同情。“原始的夜空是美丽的事物，由于人为干扰而失去它将是可耻的。”

Starlink卫星越过巴西南部的天空。

E过滤器；CC BY 4.0