In 1906, astronomer and businessman Percival Lowell launched a search for “Planet X,” a hypothetical giant orbiting the sun beyond Neptune. He was convinced of its existence because of certain irregularities he thought he had observed in the orbits of Neptune and Uranus. Although this belief led to the discovery of Pluto in 1930, scientists later determined that this dwarf planet was too small to affect Neptune’s orbit. Image illustration Pixabay
Today the existence of a hypothetical Planet X is widely discredited. This does not prevent astronomers from looking for planets in the outer reaches of the solar system. According to a recent study, such planets could exist, but would be much further away than Percival Lowell had thought.
An international team of researchers recently simulated the unstable celestial movements of the young solar system. They concluded that planet-sized bodies may have settled in the Oort Cloud, a vast assemblage of icy objects that stretches beyond the boundaries of the solar system.
About 4.5 billion years ago, during the formation of the solar system, gravity caused great chaos in debris trajectories due to the rapid cooling of the protoplanetary disk of dust. The researchers calculated that occasionally large pieces of debris – up to the size of a planet – were thrown far enough to escape the Sun’s gravity.
Scientists have already observed such “wandering planets” in interstellar space. According to the researchers, there is about a 0.5% chance that a planet could have formed in our system and still end up in the Oort Cloud as it moved away from the Sun.
However, the team thinks it’s more likely that a wandering planet, similar to Neptune, originating from another planetary system, was caught by the Sun’s gravity and settled in the Oort Cloud. The probability of this scenario is about 7%. If so, an object similar to Percival Lowell’s Planet X could exist, although too distant to affect Neptune’s orbit.
However, researchers believe it is more likely that the Oort Cloud is made up of a cluster of much smaller icy objects. Given the size and distance of the Oort Cloud, it is very difficult to determine with certainty what is hiding there.