\n
![\"EarthSnap\"\/](\"https:\/\/www.europesays.com\/uk\/wp-content\/uploads\/2025\/05\/earthsnap-banner-news.webp.webp\")
\n<\/a><\/p>\n
The idea of hidden planets<\/a> is not new. Astronomers once speculated about Planet X, which was believed to be seven times Earth\u2019s mass and orbiting 50 times farther from the Sun than Earth.<\/p>\n That idea was mostly debunked. Later came Planet Nine, a still-viable candidate about 10 times Earth\u2019s mass, at least 300 times farther from the Sun. Now, evidence is mounting for yet another contender.<\/p>\n Warped orbits suggest hidden planet<\/p>\n Amir Siraj at Princeton University<\/a> and his colleagues suggest a new possibility. They noticed a warping effect in the orbits of some Kuiper belt objects, a distant region filled with icy remnants, including Pluto. <\/p>\n \u201cIf that warp is real, the simplest explanation is an undiscovered inclined planet,\u201d Siraj said.<\/p>\n This potential world<\/a> would be smaller than Earth but larger than Mercury, orbiting 100 to 200 times farther from the Sun than Earth does. Its gravity seems to nudge nearby objects about 15 degrees out of the solar system\u2019s flat plane, like ripples disturbing a lake\u2019s surface.<\/p>\n \u201cOur signal is modest, but credible,\u201d Siraj said, estimating just a two to four percent chance of being a fluke. Early evidence for Planet Nine carried similar odds, though the signatures differ. <\/p>\n Planet Nine would tug objects toward it, while this \u201cPlanet Y\u201d appears to tilt orbits out of alignment. In theory, both worlds could exist at once.<\/p>\n Unexplained Kuiper belt tilt<\/p>\n The new research shows that if no hidden planets exist, the average plane of the Kuiper belt should align with the invariable plane of the solar system.<\/p>\n However, astronomers now detect a clear warp between 80 and 200 astronomical units (AU).<\/p>\n This tilt is unlikely to be primordial, since natural orbital precession would erase it in less than 100 million years. For the warp to persist, something must be maintaining it \u2013 such as the gravity of a hidden planet.<\/p>\n Possible Planet Y scenarios<\/p>\n Jonti Horner at the University of Southern Queensland<\/a> in Australia sees this as possible.<\/p>\n \u201cIt plays into the fact that we simply don\u2019t know what\u2019s out there. It\u2019s only in the last couple of decades that we\u2019ve really started to explore the space beyond Neptune,\u201d he said.<\/p>\n Astronomers believe such planets might not have formed so far from the Sun<\/a>. Instead, they could have been scattered outward early in the Solar System\u2019s history. \u201cScattering seems more likely,\u201d Horner said.<\/p>\n Models support Planet Y theory<\/p>\n Numerical experiments suggest that a planet with a mass between Mercury<\/a> and Earth, an orbit of roughly 100 to 200 AU, and an inclination greater than 10 degrees could maintain the observed warp.<\/p>\n Lower-mass bodies like Pluto could contribute, but far less effectively. Planets more massive than Earth would cause distortions in nearer regions, making them poor fits for the data.<\/p>\n The proposed Planet Y differs from Planet Nine in both location and influence. Planet Nine, if real, is thought to explain the clustering of orbital paths at great distances. Planet Y, by contrast, would explain why the Kuiper belt\u2019s average plane is warped.<\/p>\n \u201cThe signature is different,\u201d Siraj said, emphasizing that both ideas could coexist without contradiction.<\/p>\n Search for hidden worlds continues<\/p>\n The outer solar system is one of astronomy\u2019s greatest frontiers, and the next decade promises breakthroughs. <\/p>\n The Vera C. Rubin Observatory<\/a> will soon begin its 10-year survey, mapping the night sky in unprecedented detail. This facility could spot Planet Y directly or confirm indirect signs of its influence.<\/p>\n \u201cRubin will rapidly expand the catalog of well-measured trans-Neptunian objects,\u201d Siraj said. If Planet Y exists, \u201cwithin the survey\u2019s first few years\u201d we may either see it or gather stronger proof of its gravitational effects.<\/p>\n For now, Planet Y remains hypothetical, a hint drawn from subtle orbital patterns. But history shows that careful attention to small irregularities can reveal great discoveries. <\/p>\n From Neptune\u2019s prediction in the 19th century to Pluto\u2019s identification in the 20th, the search for hidden worlds has always reshaped our cosmic understanding. If Planet Y is real, it may soon step from speculation into fact.<\/p>\n The study is published in arXiv<\/a>.<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.\u00a0<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"For centuries, humans have gazed into the night sky, wondering what lies beyond the planets we know. Each…\n","protected":false},"author":2,"featured_media":370221,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3844],"tags":[70,413,16,15],"class_list":{"0":"post-370220","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-science","9":"tag-space","10":"tag-uk","11":"tag-united-kingdom"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@uk\/115084847235825658","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/370220","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/comments?post=370220"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/370220\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media\/370221"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media?parent=370220"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/categories?post=370220"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/tags?post=370220"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}