Fictional planets of the Solar System 40 Eridani A. Counter-Earth was a hypothetical planet sharing an orbit with Earth, but on the opposite side of the Sun (hence Earth and Counter-Earth would always be invisible to each other). The idea of a counter-Earth has never been a serious scientific hypothesis in modern times. Phaëton is a name given to a supposed planet existing in the past between the orbits of Mars and Jupiter, which no longer exists, having become the Solar System's asteroid belt. Proposed not long after the discovery of multiple asteroids at the beginning of the 19th century, the idea that the asteroids were
Stability of the Solar System it. Though they are not technically part of the solar system for the purposes of studying the system's intrinsic stability, they nevertheless can change the system. Unfortunately predicting the potential influences of these extrasolar objects is even more difficult than predicting the influences of objects within the system simply because of the sheer distances involved. Among the known objects with a potential to significantly impact the solar system is the star Gliese 710, which is expected to pass near the system in approximately 1.35 million years. Though the star is not expected to substantially affect the orbits of the major