New research suggests Planet Nine is what’s called a rogue planet
The rogue planets have just had their unfortunate introduction into public consciousness via a particularly stupid conspiracy theory involving a collision and the end of the world that ensues. Let’s not allow this to bury new research on them, because that’s what is definitely worth your time.
Researchers testing whether a highly mythologized object called Planet Nine could indeed be a captured rogue planet found it certainly looked like one. They also performed simulations of different types of dishonest encounters with our solar system; they discovered that if the thief had a mass equal to or greater than that of Jupiter, it could subsequently leave a physical impact on the configuration of the entire system. James Vesper of New Mexico State University presented the research on Friday at the 229th American Astronomical Sciences Meeting in Grapevine, Texas.
We can easily imagine stars that don’t have planets, but it’s a bit strange to imagine upside down (sorry) – floating planets that roll around in space, not attached to any sort of regular orbit, either because they escaped their original host star or because they never formed around a single one to begin with. These planets are rogue planets, and they often tend to be “captured” by a new star as they roam its system.
Vesper said their data showed 60% of all rogue encounters were “slingshot” in the galaxy – they approached the sun and then left. About ten percent of these encounters carry one or more planets with them. If two or more planets are knocked out – but the thief is captured – Vesper calls the trade a “kick and stay”.
Planet Nine, the newly created ninth planet in our solar system, is about ten times the size of Earth and has been notoriously difficult to observe directly.
There are dozens of rogue planets in our galaxy – perhaps billions – and a handful relatively close to our own solar system. There is enough of them to provide an explanation for some of the dark matter in the Milky Way’s disk, and they actually outnumber the stars.