 It might be lingering bashfully on the icy outer edges of our solar system, hiding in the dark, but subtly pulling strings behind the scenes: stretching out the orbits of distant bodies, perhaps even tilting the entire solar system to one side. If a planet is there, it's extremely distant and will stay that way (with no chance -- in case you're wondering -- of ever colliding with Earth, or bringing "days of darkness").It is a possible "Planet Nine" -- a world perhaps 10 times the mass of Earth and 20 times farther from the sun than Neptune. One of its most dedicated trackers, in fact, says it is now harder to imagine our solar system without a Planet Nine than with one. "There are now five different lines of observational evidence pointing to the existence of Planet Nine," Konstantin Batygin, a planetary astrophysicist at the California Institute of Technology (Caltech) in Pasadena, said in the statement. "If you were to remove this explanation and imagine Planet Nine does not exist, then you generate more problems than you solve. All of a sudden, you have five different puzzles, and you must come up with five different theories to explain them," Batygin explains. Batygin and his co-author, Caltech astronomer Mike Brown, described the first three breadcrumbs on Planet Nine's trail in a January 2016 paper, published in the Astronomical Journal. Credit: by Karl Tate, Infographics artist 
 
 In 2016, Batygin and co-author Mike Brown, an astronomer at Caltech, published a study that examined the elliptical orbits of six known objects in the Kuiper Belt, a distant region of icy bodies stretching from Neptune outward toward interstellar space. Their findings revealed that all of those Kuiper Belt objects have elliptical orbits that point in the same direction and are tilted about 30 degrees "downward" compared to the plane in which the eight official planets circle the sun, according to the statement. Using computer simulations of the solar system with a Planet Nine, Batygin and Brown also showed that there should be even more objects tilted a whopping 90 degrees with respect to the solar plane. Two more clues emerged after the original paper. With help from Elizabeth Bailey, an astrophysicist and planetary scientist at Caltech, the team showed that Planet Nine's influence might have tilted the planets of our solar system, which would explain why the zone in which the eight major planets orbit the sun is tilted by about 6 degrees compared to the sun's equator. And its aforementioned influence on the entire solar system takes place subtly and over a very long timescale 
 
 "Over long periods of time, Planet Nine will make the entire solar-system plane precess or wobble, just like a top on a table," Batygin said. The last telltale sign of Planet Nine's presence involves the solar system's contrarians: objects from the Kuiper Belt that orbit in the opposite direction from everything else in the solar system. [The Evidence for 'Planet Nine' in Our Solar System (Gallery)] 
 
 Researchers say an anomaly in the orbits of distant Kuiper Belt objects points to the existence of an unknown planet orbiting the sun. "No other model can explain the weirdness of these high-inclination orbits," Batygin said in the statement. "It turns out that Planet Nine provides a natural avenue for their generation. These things have been twisted out of the solar system plane with help from Planet Nine and then scattered inward by Neptune." Going forward, the researchers plan to use the Subaru Telescope at Mauna Kea Observatory in Hawaii to find Planet Nine, and then deduce where the mysterious world came from. The instrument is the "best tool" for picking out dim, extremely distant objects lost in huge swaths of sky, Batygin said. Over the past 20 years, surveys of planets around other stars in our galaxy have found the most common types to be "super Earths" and their somewhat larger cousins -- bigger than Earth but smaller than Neptune. However, no such planet has yet been discovered in our solar system, meaning that Planet Nine could be our missing "super Earth," the researchers said.
– Astronomically inclined conspiracy theorists have long been predicting the Earth's demise in a collision with a rogue planet called "Niburu" or "Planet X" biding its time out of sight somewhere in the solar system, CNET reports. In fact, Niburu was "supposed" to crash into Earth just last month. And while death-by-planet remains unlikely, the existence of an undiscovered planet in our solar system is now almost a certainty, according to NASA. Planetary astrophysicist Konstantin Batygin and professor Mike Brown set out to disprove the existence of a hidden planet a few years ago and, ironically, ended up finding convincing evidence for the existence of what they call "Planet Nine." The main evidence for Planet Nine comes from its "gravitational footprint," but it's convincing enough that Batygin says the solar system makes a lot more sense with the hidden planet than without it, Space.com reports. Planet Nine is believed to be 10 times more massive than Earth and located about 20 times farther from the sun than Neptune. From its position in the far reaches of the solar system, it has tilted and reversed the orbits of objects in the Kuiper Belt, according to Batygin and Brown. It also may be the reason the orbits of the planets are slightly off from the sun's equator. Finally, Planet Nine could be the "super Earth" frequently found orbiting other stars but "conspicuously absent" around ours. Oh, and NASA wants conspiracy theorists to know Planet Nine, if it exists, is staying far away from Earth. (Scientists just found the smallest possible star.)