In this short review, we discuss how Earth’s climatological and geological history and also how the shadows of galactic black holes might reveal our Universe’s past evolution. Specifically we point out that a pressure singularity that occurred in our Universe’s past might have left its imprint on Earth’s geological and climatological history and on the shadows of cosmological black holes. Our approach is based on the fact that the $H_0$ tension problem may be resolved if some sort of abrupt physics change occurred in our Universe 70–150 Myrs ago, an abrupt change that deeply affected the Cepheid parameters. We review how such an abrupt physics change might have been caused in our Universe by a smooth passage of it through a pressure finite-time singularity. Such finite-time singularities might occur in modified gravity and specifically in $F\left(R\right)$ gravity, so we show how modified gravity might drive this type of evolution, without resorting to peculiar cosmic fluids or scalar fields. The presence of such a pressure singularity can distort the elliptic trajectories of bound objects in the Universe, causing possible geological and climatological changes on Earth, if its elliptic trajectory around the Sun might have changed. Also, such a pressure singularity affects directly the circular photon orbits around supermassive galactic black holes existing at cosmological redshift distances, thus the shadows of some cosmological black holes at redshifts $z\le 0.01$, might look different in shape, compared with the SgrA* and M87* supermassive black holes. This feature however can be checked experimentally in the very far future.

中文翻译：

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利用地球的地质和气候历史以及银河黑洞的阴影探索我们宇宙的过去

在这篇简短的回顾中，我们讨论了地球的气候和地质历史，以及银河黑洞的阴影如何揭示我们宇宙过去的演化。具体来说，我们指出，我们宇宙过去发生的压力奇点可能已经在地球的地质和气候历史以及宇宙黑洞的阴影中留下了印记。我们的方法是基于以下事实：$H_0$如果在我们的宇宙 70-150 Myrs 之前发生某种突然的物理变化，那么张力问题可能会得到解决，这种突然变化深深地影响了造父变星的参数。我们回顾了宇宙中如此突然的物理变化是如何通过压力有限时间奇点顺利通过而引起的。这种有限时间奇点可能发生在修正重力中，特别是在$F\left(R\right)$重力，因此我们展示了修改后的重力如何驱动这种类型的进化，而不诉诸特殊的宇宙流体或标量场。这种压力奇点的存在可能会扭曲宇宙中束缚物体的椭圆轨迹，如果地球围绕太阳的椭圆轨迹可能发生变化，可能会导致地球上的地质和气候变化。此外，这种压力奇点直接影响存在于宇宙学红移距离处的超大质量星系黑洞周围的圆形光子轨道，因此一些宇宙学黑洞在红移处的阴影$z\le 0.01$，与 SgrA* 和 M87* 超大质量黑洞相比，其形状可能看起来不同。然而，这个特性可以在很远的将来通过实验进行检查。