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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 best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a young protostar orbited by a protoplanetary disk. There are eight planets within the Solar System; planets outside of the solar system are also known as exoplanets.
The Sun, planets, moons and dwarf planets (true color, size to scale, distances not to scale) The following outline is provided as an overview of and topical guide to the Solar System: Solar System – gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly. Of those objects that orbit the ...
The following is a list of Solar System objects by orbit, ordered by increasing distance from the Sun. Most named objects in this list have a diameter of 500 km or more. The Sun, a spectral class G2V main-sequence star; The inner Solar System and the terrestrial planets. 2021 PH27; Mercury. Mercury-crossing minor planets; Venus. Venus-crossing ...
The Sun and planets of the Solar System (distances not to scale). The Solar System is the gravitationally bound system of the Sun and the objects that orbit it. It formed about 4.6 billion years ago when a dense region of a molecular cloud collapsed, forming the Sun and a protoplanetary disc.
A class of extrasolar planets whose characteristics are similar to Jupiter, but that have high surface temperatures because they orbit very close—between approximately 0.015 and 0.5 AU (2.2 × 10 ^ 6 and 74.8 × 10 ^ 6 km)—to their parent stars, whereas Jupiter orbits its parent star (the Sun) at 5.2 AU (780 × 10 ^ 6 km), causing low ...
For the giant planets, the "radius" is defined as the distance from the center at which the atmosphere reaches 1 bar of atmospheric pressure. [ 11 ] Because Sedna and 2002 MS 4 have no known moons, directly determining their mass is impossible without sending a probe (estimated to be from 1.7x10 21 to 6.1×10 21 kg for Sedna [ 12 ] ).
In ancient times, only the Sun and Moon, a few stars, and the most easily visible planets had names. Over the last few hundred years, the number of identified astronomical objects has risen from hundreds to over a billion, and more are discovered every year.