Mysterious ‘unseen planetary mass’ lurking at edge of solar system Prison Planet.com Posted on June 23, 2017 Posted in Aggregated No Comments Tagged with Sci Tech RT | A mysterious, unseen, planetary object with a mass somewhere between that of Mars and Earth may be lurking in the outer reaches of our solar system, according to new research. Share this:Share Share on Facebook (Opens in new window) Facebook Share on Reddit (Opens in new window) Reddit Share on X (Opens in new window) X Share on LinkedIn (Opens in new window) LinkedIn Email a link to a friend (Opens in new window) Email