WHILE NASA grapples with the mysteries of Planet Nine using modern telescopes and hi-tech probes, two researchers are taking a trip back in time to find the hypothetical world.
The duo from Queenâ€™s University Belfast, in Northern Ireland, are looking to Anglo-Saxons for clues of the super-Earthâ€™s existence and theyâ€™re sharing their findings with the public.
Medievalist Marilina Cesario and astronomer Pedro Lacerda are scouring a wealth of ancient tapestries and scrolls from the Dark Ages looking for evidence of a ninth planet in our solar system and whether it was mentioned in any type of historical record.
These documents include artistic depictions of comets lighting up the night sky and other astronomical events that captured peopleâ€™s attention during medieval times.
Speculation over the existence of Planet Nine began in 2014, with experts hypothesising it is a gigantic icy planet, about 10 times larger than Earth and 20 times farther away from the sun than Neptune.
Conspiracy theorists recently claimed that a similar world called Nibiru was going to plunge into Earth on April 23 and trigger a Biblical-level apocalypse.
But that obviously didnâ€™t happen.
And while NASA has said that itâ€™s â€śclosing inâ€ť on Planet Nine, it has repeatedly denied Nibiruâ€™s existence, even branding it a falsification.
The space agency has also put forth five pieces of evidence for the existence of the mysterious world.
Some of these clues relate to the gravitational tug of Planet Nine, which appears to be disturbing the distant Kuiper Belt that is populated with icy objects and stretches from Neptune out into deep space.
Back on Earth, Dr Cesario and Dr Lacerda have put together an exhibition called â€śMarvelling At The skies: Comets Through The Eyes Of The Anglo-Saxonsâ€ť that combines modern astronomy with theories from the Dark Ages.
â€śWe have a wealth of historical records of comets in Old English, Old Irish, Latin and Russian which have been overlooked for a long time,â€ť Dr Cesario told Live Science.
â€śEarly medieval people were fascinated by the heavens, as much as we are today.â€ť
One of these documents includes a report of the 1066 appearance of Halleyâ€™s comet, which is also enshrined in the famous Bayeux tapestry â€” an embroidered cloth that stretches 70m and depicts the events surrounding the Norman Conquest of England.
The Anglo-Saxons of the Dark Ages called comets â€śfeaxedaâ€ť or â€ślong-haired stars,â€ť according to Queenâ€™s University Belfast.
And despite the perception of that period as unscientific, they demonstrated â€śa genuine interest in astronomy and an attempt to rationalise and systematise the world around them,â€ť Dr Cesario told Live Science.