Formation and evolution of the Solar System apart by tidal interactions. Afterwards, all that will remain of the Sun is a white dwarf, an extraordinarily dense object, 54% its original mass but only the size of the Earth. Initially, this white dwarf may be 100 times as luminous as the Sun is now. It will consist entirely of degenerate carbon and oxygen, but will never reach temperatures hot enough to fuse these elements. Thus the white dwarf Sun will gradually cool, growing dimmer and dimmer. As the Sun dies, its gravitational pull on the orbiting bodies such as planets, comets and asteroids will weaken due to its
Counter-Earth if a Counter-Earth existed, as the navigational calculations for their journeys did not take any putative Counter-Earth into account. Roughly speaking, anything larger than in diameter should have been detected. Furthermore, the gravitational forces of the other planets on a Counter-Earth would make "its" orbit unstable. Venus has 82% of the mass of Earth and would come within 0.3 AU of the location of a Counter-Earth every 20 months, providing considerable gravitational pull that over the years would move its orbit into sight of observers on Earth. If a Counter-Earth was much smaller than Earth, its location at the "Sun–Earth