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In the asteroid belt alone there are estimated to be between 1.1 and 1.9 million objects with a radius above 0.5 km, many of which are in the range 0.5–1.0 km. Countless more have a radius below 0.5 km. Very few objects in this size range have been explored or even imaged. The exceptions are objects that have been visited by a probe, or have ...
Jupiter is the fifth planet from the Sun and the largest in the Solar System.A gas giant, Jupiter's mass is more than two and a half times that of all the other planets in the Solar System combined and slightly less than one one-thousandth the mass of the Sun. Jupiter orbits the Sun at a distance of 5.20 AU (778.5 Gm) with an orbital period of 11.86 years.
Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main-sequence stars.Their mass is approximately 13 to 80 times that of Jupiter (M J) —not big enough to sustain nuclear fusion of ordinary hydrogen (1 H) into helium in their cores, but massive enough to emit some light and heat from the fusion of deuterium (2 H).
Many TNOs in the size range of about 400–1000 km have oddly low densities, in the range of about 1.0–1.2 g/cm 3, that are substantially less than those of dwarf planets such as Pluto, Eris and Ceres, which have densities closer to 2. Brown has suggested that large low-density bodies must be composed almost entirely of water ice since he ...
The sizes are listed in units of Jupiter radii (71,492 km). All planets listed are larger than 1.7 times the size of the largest planet in the Solar System, Jupiter. Some planets that are smaller than 1.7 R J have been included for the sake of comparison.
The largest planet, Jupiter, is 0.09% the mass of the Sun, while the Earth is about three millionths (0.0003%) of the mass of the Sun. When comparing the planets among themselves, it is often convenient to use the mass of the Earth (M E or M E) as a standard, particularly for the terrestrial planets.
The discovery of the low-density Earth-mass planet Kepler-138d shows that there is an overlapping range of masses in which both rocky planets and low-density planets occur. A low-mass low-density planets could be an ocean planet or super-Earth with a remnant hydrogen atmosphere, or a hot planet with a steam atmosphere, or a mini-Neptune with a ...
The mean apparent magnitude is 0.23 while the standard deviation of 1.78 is the largest of any planet. The mean apparent magnitude at superior conjunction is −1.89 while that at inferior conjunction is +5.93. Observation of Mercury is complicated by its proximity to the Sun, as it is lost in the Sun's glare for much of the time.