We really shouldn’t be surprised that it is hard to understand alien solar systems. After all, we still haven’t fully sorted our own solar system! It’s been known for several years that the orbits of icy objects point toward there being a massive Planet 9 in the outer solar system. Now, a review paper by Brett Gladman and Kathryn Volk hints that maybe, just maybe, another Mars-sized world is out there too. We’re going to try and get the researchers on our show so they can explain this exciting news themselves. I, for one, welcome future planet discoveries.

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Evidence Indicates There’s Another Planet the Size of Mars in Our Solar System (Interesting Engineering)

“Transneptunian Space,” Brett Gladman and Kathryn Volk, 2021 September, Annual Review of Astronomy and Astrophysics