Have you ever wondered if there’s more to our Solar System than meets the eye? Scientists might have just unearthed a tantalizing clue suggesting there could be an undiscovered planet lurking between Earth and Mercury!

For centuries, the far reaches of our Solar System have been shrouded in mystery, even as spacecraft like the Voyager probes venture into the void of interstellar space. While these probes have stretched our understanding of the cosmos, the boundaries of our Solar System remain elusive. Beyond Neptune, a vast expanse filled with icy bodies lies waiting, and now, it seems, a possible new planet might be hiding in the shadows.

A groundbreaking study has revealed evidence of a distortion, or a peculiar 'warp,' in the orbital plane of Trans-Neptunian Objects (TNOs) at a staggering distance of 80 to 400 astronomical units (AU) from the Sun. This subtle twist could imply the gravitational influence of an unseen world, a hypothetical Planet Y, stirring excitement and speculation in the astronomy community.

Researchers conducted a meticulous analysis of non-resonant TNOs, measuring their mean orbital plane while filtering out bodies influenced by Neptune. The results were astonishing: they found that the TNOs’ orbits were tilted by about 15° compared to the Solar System's invariable plane, raising eyebrows and sparking debate. With a mere 2–4% chance that this warp could be a coincidence, the implications are profound.

So, what does this all mean? Siraj and his research team suggest that Planet Y could have a mass somewhere between that of Mercury and Earth and might be orbiting at a distance of 100–200 AU, with an inclination of over 10°. While the legendary Planet Nine has often been the subject of heated discussions—speculated to be a giant world lurking far beyond our current knowledge—Planet Y presents a different narrative altogether. It’s smaller and potentially much closer.

But the search for Planet Y is far from over. The Vera Rubin Observatory's upcoming Legacy Survey of Space and Time (LSST) is set to test these theories, making it possible for us to capture more insights into the enigmatic Kuiper Belt. As IFLScience points out, even if this hypothetical planet remains elusive due to its position in the sky, the LSST will enhance our understanding of the mysterious warp affecting the Kuiper Belt mean plane.

If Planet Y does exist, it could have originated as a rocky embryo from the chaotic formation of our Solar System, only to be scattered into the outer reaches during the planet-building process. Siraj theorizes that during this tumultuous era, many Mercury-sized bodies were ejected, but perhaps one has bravely remained hidden, waiting for its moment in the cosmic spotlight.