Planet Nine May Have Once Been an Exoplanet

Is there a "dark Neptune" lurking at the extreme edge of the Solar System?
“Planet Nine” could be an exoplanet in our own Solar System

It hasn’t even been found yet (they’re still working on that) but the recently-announced Planet Nine is already spurring discussion amongst the world’s astronomers. One of the recent topics surrounding this alleged new planet is (again, besides where it’s hiding) how it formed and how it got into the incredibly distant orbit it’s thought to be in. Estimated to be nearly as massive as Neptune, and possibly similarly gaseous as well, Planet Nine would be an anomaly among the small frozen balls of ice that typically haunt the outer Solar System. Recently, a team of scientists decided to investigate the possibility that Planet Nine did not originate in our Solar System at all but rather was captured from another star, back when the Sun’s stellar family was much closer together… and apparently much more trusting. (That’ll teach ’em.)

Read the full story in my article on Universe Today here.


  1. Mr. Hematite says:

    Very interesting. I originally dismissed the notion that there actually might be a ninth planet, mostly because of how many claims there have been about such a thing over the years. But, now that orbital evidence points to it being legit, the fact that it may be a gas giant is baffling. You wouldn’t think volatiles would be pushed so far during stellar birth without leaving the sun’s gravitational neighbourhood completely. This theory sounds compelling!


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