Solar System  and  Details about all the planets | All related information about Solar System
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Date: 23/09/2020

Solar System
This article is about the Sun and its planetary system. For other similar systems, see Planetary system.
Solar System
A representative image of the Solar System with sizes, but not distances, to scale
The Sun and planets
(distances not to scale)
Age 4.568 billion years
Location Local Interstellar Cloud, Local Bubble, Orion–Cygnus Arm, Milky Way
System mass 1.0014 Solar masses
Nearest star 
Proxima Centauri (4.25 ly)
Alpha Centauri (4.37 ly)
Nearest known planetary system Proxima Centauri system (4.25 ly)
Planetary system
Semi-major axis of outer known planet (Neptune) 30.10 AU
(4.5 bill. km; 2.8 bill. mi)
Distance to Kuiper cliff 50 AU
Populations
Stars 1 (Sun)
Known planets 
8 (MercuryVenusEarthMarsJupiterSaturnUranusNeptune)
Known dwarf planets 2 universally accepted
(PlutoEris)
1 more likely to be
(Ceres)
2 more possible to be
(HaumeaMakemake)
Known natural satellites 
575 (185 planetary390 minor planetary)[1][2]
Known minor planets 796,354[a][3]
Known comets 4,143[a][3]
Identified rounded satellites 19 (5–6 likely in hydrostatic equilibrium)
Orbit about Galactic Center
Invariable-to-galactic plane inclination 60.19° (ecliptic)
Distance to Galactic Center 27,000 ± 1,000 ly
Orbital speed 220 km/s; 136 mps
Orbital period 225–250 myr
Star-related properties
Spectral type G2V
Frost line ≈5 AU[4]
Distance to heliopause ≈120 AU
Hill sphere radius ≈1–3 ly
Solar System
Solar sys8.jpg
Objects
by orbitby sizeby discovery datemodels
Lists
Gravitationally-rounded
(equilibrium) objects
Possible dwarf planets
Moons (natural satellites)
Planetary-mass moons
Minor planets
CometsAsteroids
Planets
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Solar system.jpg Solar System portal
He1523a.jpg Star portal
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The Solar System[b] is the gravitationally bound system of the Sun and the objects that orbit it, either directly or indirectly.[c] Of the objects that orbit the Sun directly, the largest are the eight planets,[d] with the remainder being smaller objects, the dwarf planets and small Solar System bodies. Of the objects that orbit the Sun indirectly—the moons—two are larger than the smallest planet, Mercury.[e]

The Solar System formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority of the system's mass is in the Sun, with the majority of the remaining mass contained in Jupiter. The four smaller inner planets, Mercury, Venus, Earth and Mars, are terrestrial planets, being primarily composed of rock and metal. The four outer planets are giant planets, being substantially more massive than the terrestrials. The two largest planets, Jupiter and Saturn, are gas giants, being composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are ice giants, being composed mostly of substances with relatively high melting points compared with hydrogen and helium, called volatiles, such as water, ammonia and methane. All eight planets have almost circular orbits that lie within a nearly flat disc called the ecliptic.

The Solar System also contains smaller objects.[f] The asteroid belt, which lies between the orbits of Mars and Jupiter, mostly contains objects composed, like the terrestrial planets, of rock and metal. Beyond Neptune's orbit lie the Kuiper belt and scattered disc, which are populations of trans-Neptunian objects composed mostly of ices, and beyond them a newly discovered population of sednoids. Within these populations, some objects are large enough to have rounded under their own gravity, though there is considerable debate as to how many there will prove to be.[9][10] Such objects are categorized as dwarf planets. The only certain dwarf planet is Pluto, with another trans-Neptunian object, Eris, expected to be, and the asteroid Ceres at least close to being a dwarf planet.[f] In addition to these two regions, various other small-body populations, including comets, centaurs and interplanetary dust clouds, freely travel between regions. Six of the planets, the six largest possible dwarf planets, and many of the smaller bodies are orbited by natural satellites, usually termed "moons" after the Moon. Each of the outer planets is encircled by planetary rings of dust and other small objects.

The solar wind, a stream of charged particles flowing outwards from the Sun, creates a bubble-like region in the interstellar medium known as the heliosphere. The heliopause is the point at which pressure from the solar wind is equal to the opposing pressure of the interstellar medium; it extends out to the edge of the scattered disc. The Oort cloud, which is thought to be the source for long-period comets, may also exist at a distance roughly a thousand times further than the heliosphere. The Solar System is located in the Orion Arm, 26,000 light-years from the center of the Milky Way galaxy.