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
Lada Terra remnants. The most prominent region is the midlands, where gently sloping topography is disrupted by faults, fractures, and corona, making this area the most complex and studied region in Lada Terra. The western portion of Lada Terra contains a large dome-shaped structure about across termed, "the Lada Rise," which is the main highland of the region. It reaches an elevation of about and is dominated by one of the most massive corona in the solar system, the Quetzalpetlatl Corona, as well as two massive rift zones surround and partially intersect the rise. The high rises of Venus generally fall into