
Astronomers now doubt there is an undiscovered 9th planet in our solar system - spchampion2
https://phys.org/news/2020-05-astronomers-undiscovered-9th-planet-solar.html
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Cactus2018
On the other hand, 'If Planet Nine Is a Tiny Black Hole, This Is How to Find
It'
[https://news.ycombinator.com/item?id=23132488](https://news.ycombinator.com/item?id=23132488)

> The black hole in this scenario is neither infinitely massive nor infinitely
> small... 10 times more massive than Earth and five cm across.

