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Currently most of the objects of mass between 10 9 kg to 10 12 kg (less than 1000 teragrams (Tg)) listed here are near-Earth asteroids (NEAs). The Aten asteroid 1994 WR12 has less mass than the Great Pyramid of Giza, 5.9 × 10 9 kg. For more about very small objects in the Solar System, see meteoroid, micrometeoroid, cosmic dust, and ...
Mercury (planet) Surface temp. Mercury is the first planet from the Sun and the smallest in the Solar System. In English, it is named after the ancient Roman god Mercurius ( Mercury ), god of commerce and communication, and the messenger of the gods. Mercury is classified as a terrestrial planet, with roughly the same surface gravity as Mars.
Thus, the Sun occupies 0.00001% (1 part in 10 7) of the volume of a sphere with a radius the size of Earth's orbit, whereas Earth's volume is roughly 1 millionth (10 −6) that of the Sun. Jupiter, the largest planet, is 5.2 AU from the Sun and has a radius of 71,000 km (0.00047 AU; 44,000 mi), whereas the most distant planet, Neptune, is 30 AU ...
The first image compares some of the largest TNOs in terms of size, color and albedo. This is a list of trans-Neptunian objects (TNOs), which are minor planets in the Solar System that orbit the Sun at a greater distance on average than Neptune , that is, their orbit has a semi-major axis greater than 30.1 astronomical units (AU).
A dwarf planet is a small planetary-mass object that is in direct orbit around the Sun, massive enough to be gravitationally rounded, but insufficient to achieve orbital dominance like the eight classical planets of the Solar System.
The number of dwarf planets in the Solar System is unknown. Estimates have run as high as 200 in the Kuiper belt and over 10,000 in the region beyond. 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 bodies ...
Sub-Earth exoplanets are among the most difficult type to detect because their small sizes and masses produce the weakest signal. Despite the difficulty, one of the first exoplanets found was a sub-Earth around a millisecond pulsar PSR B1257+12. The smallest known is WD 1145+017 b with a size of 0.15 Earth radii, or somewhat smaller than Pluto.
Planetary mass. In astronomy, planetary mass is a measure of the mass of a planet -like astronomical object. Within the Solar System, planets are usually measured in the astronomical system of units, where the unit of mass is the solar mass ( M☉ ), the mass of the Sun. In the study of extrasolar planets, the unit of measure is typically the ...