Japanese astronomers have made an intriguing discovery that hints at the possible existence of an "Earth-like planet" within our own solar system. The planet is believed to be in the Kuiper Belt, a region consisting of various celestial objects encircling the outer reaches of our solar system, just beyond Neptune's orbit. Similar to the familiar planets we know, these Kuiper Belt objects orbit around the Sun.

The astronomers behind this discovery, Patryk Sofia Lykawka from Kindai University in Osaka and Takashi Ito from the National Astronomical Observatory of Japan in Tokyo, have published their findings in The Astronomical Journal. According to their research, if this hypothetical planet does indeed exist, it would measure roughly 1.5 to 3 times the size of our Earth.

This discovery raises questions and challenges previous theories about the existence of a distant ninth planet, often referred to as "Planet Nine," thought to be lurking in the outer realms of our solar system. The astronomers suggest that instead of Planet Nine, there could be another undiscovered celestial body much closer, right within the Kuiper Belt itself.

The researchers explain their findings by stating, "We predict the existence of an Earth-like planet and several trans-Neptunian objects on peculiar orbits in the outer solar system, which can serve as observationally testable signatures of the putative planet's perturbations." By closely examining the clustering patterns of these trans-Neptunian objects (TNOs), the scientists propose that this mysterious planet could be positioned anywhere from 200 to 500 astronomical units (AU) away from the Sun and tilted at an angle of approximately 30 degrees.

In their conclusion, the research team states, "The results of the Kuiper Belt planet scenario support the existence of a yet-undiscovered planet in the far outer Solar System. More detailed knowledge of the orbital structure in the distant Kuiper Belt can reveal or rule out the existence of any hypothetical planet in the outer solar system." This discovery opens up exciting prospects for further exploration and understanding of our solar system's outer reaches, challenging our existing understanding of its celestial dynamics.