Search results
Results from the WOW.Com Content Network
The prototypical dwarf planet is Pluto, which for decades was regarded as a planet before the "dwarf" concept was adopted in 2006. Dwarf planets are capable of being geologically active, an expectation that was borne out in 2015 by the Dawn mission to Ceres and the New Horizons mission to Pluto.
The number of dwarf planets in the Solar System is unknown. Estimates have run as high as 200 in the Kuiper belt [1] and over 10,000 in the region beyond. [2] However, consideration of the surprisingly low densities of many large trans-Neptunian objects, as well as spectroscopic analysis of their surfaces, suggests that the number of dwarf planets may be much lower, perhaps only nine among ...
Since Pluto's reclassification as a dwarf planet in 2006 by the International Astronomical Union (IAU), space exploration has increasingly focused on these celestial bodies. In 2015 significant milestones in dwarf planet exploration were reached with the flybys of Pluto and Ceres by the New Horizons and Dawn spacecraft. [1] [2]
Counter-Earth, a planet situated on the other side of the Sun from that of the Earth. Fifth planet (hypothetical), historical speculation about a planet between the orbits of Mars and Jupiter. Phaeton, a planet situated between the orbits of Mars and Jupiter whose destruction supposedly led to the formation of the asteroid belt. This hypothesis ...
When the spacecraft was launched, Pluto was still classified as a planet, later to be reclassified as a dwarf planet by the International Astronomical Union (IAU). Some members of the New Horizons team, including Alan Stern, disagree with the IAU definition and still describe Pluto as the ninth planet. [38]
Four test orbits of a trans-Plutonian planet have been integrated forward for four million years in order to determine the effects of such a body on the stability of the Neptune–Pluto 3:2 resonance. Planets beyond Pluto with masses of 0.1 and 1.0 Earth masses in orbits at 48.3 and 75.5 AU, respectively, do not disturb the 3:2 resonance.
It is not clear how many KBOs are large enough to be dwarf planets. Consideration of the surprisingly low densities of many dwarf-planet candidates suggests that not many are. [113] Orcus, Pluto, Haumea, Quaoar, and Makemake are accepted by most astronomers; some have proposed other bodies, such as Salacia, 2002 MS 4, [114] 2002 AW 197, and ...
Additional planets in the outer reaches of the Solar System, such as a ninth planet beyond Neptune or especially a tenth beyond Pluto (between the 1930 discovery of Pluto and its reclassification from planet to dwarf planet in 2006), appear regularly. Many different names for this hypothetical outermost planet have been used, the most common ...