It’s been hypothesised for years, yet definitive proof of a ninth planet in our solar system is yet to appear. Now, scientists claim that Planet Nine does exist – but it may be invisible to telescopes. Speaking to the Washington Post , Dr Surhud More, an associated professor at the Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo, explained that Planet Nine may be lurking just beyond Neptune. He said: “Every time we take a picture there is this possibility that Planet Nine exists in the shot.” Planet Nine was first hypothesised in 2014, when scientists discovered a number of mini ice-worlds in the outermost edgers of the solar system, that all followed similar paths around the sun. Scott Shepherd, an astronomer at the Carnegie Institution for Science in Washington, who discovered the mini ice-worlds, said: “If things are in the same orbit, then something’s pushing them.” Further studies suggested that this ‘pusher’ was a planet weighing between five and 20 more than Earth, and lying 1,000 times further away from the sun than our planet. Unfortunately, this distance makes Planet Nine difficult to spot with telescopes currently available. To overcome this hurdle, researchers are looking for other ways to detect the planet – including looking at its heat glow.