Back Sonnestelsel Afrikaans Sonnensystem ALS Кӱнниҥ системазы ALT የፀሐይ ሥርዓተ ፈለክ Amharic Sistema Solar AN Sunnlicu Endebyrdnes ANG सौरमंडल ANP المجموعة الشمسية Arabic النضام الشمسي ARY نظام شمسى ARZ
 | |
| Age | 4.568 billion years |
|---|---|
| Location | |
| Nearest star |
|
| Nearest planetary system | Proxima Centauri system (4.2465 ly) |
| Planetary system | |
| Semi-major axis of outer known planet | |
| Distance to Kuiper cliff | ~50 AU |
| Populations | |
| Stars | 1 (Sun) |
| Known planets | |
| Known dwarf planets | |
| Known natural satellites |
|
| Known minor planets | 1,358,412[b][2] |
| Known comets | 4,591[b][2] |
| Identified rounded satellites | 19 |
| 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 mi/s |
| Orbital period | 225–250 million years |
| Parent star properties | |
| Spectral type | G2V |
| Frost line | ≈5 AU[3] |
| Distance to heliopause | ≈120 AU |
| Hill sphere radius | ≈1–3 ly |
The Solar System[c] is the gravitationally bound system of the Sun and the objects that orbit it.[4] It was formed 4.6 billion years ago when a dense region of a molecular cloud collapsed, forming the Sun and a protoplanetary disc. The Sun is an ordinary main sequence star that maintains a balanced equilibrium by the fusion of hydrogen into helium at its core, releasing this energy from its outer photosphere.
The largest objects that orbit the Sun are the eight planets. In order from the Sun, they are four terrestrial planets (Mercury, Venus, Earth and Mars); two gas giants (Jupiter and Saturn); and two ice giants (Uranus and Neptune). All terrestrial planets have solid surfaces. Inversely, all giant planets do not have a definite surface, as they are mainly composed of gases and liquids. Over 99.86% of the Solar System's mass is in the Sun and nearly 90% of the remaining mass is in Jupiter and Saturn.
There is a strong consensus among astronomers[d] that the Solar System has at least eight dwarf planets: Ceres, Pluto, Haumea, Quaoar, Makemake, Gonggong, Eris, and Sedna. There are a vast number of small Solar System bodies, such as asteroids, comets, centaurs, meteoroids, and interplanetary dust clouds. Some of these bodies are in the asteroid belt (between Mars's and Jupiter's orbit) and the Kuiper belt (just outside Neptune's orbit).[e] Six planets, six dwarf planets, and other bodies have orbiting natural satellites, which are commonly called 'moons'.
The Solar System is constantly flooded by the Sun's charged particles, the solar wind, forming the heliosphere. Around 75–90 astronomical units, the solar wind is halted, resulting in the heliopause. This is the boundary of the Solar System to interstellar space. The outermost region of the Solar System is the theorized Oort cloud, the source for long-period comets, extending 2,000–200,000 astronomical units (0.032–3.2 light-years). The closest star to the Solar System, Proxima Centauri, is 4.25 light-years away. Both stars belong to the Local Group and the Milky Way galaxy.
Cite error: There are <ref group=lower-alpha> tags or {{efn}} templates on this page, but the references will not show without a {{reflist|group=lower-alpha}} template or {{notelist}} template (see the help page).
- ^ "Solar System Objects". NASA/JPL Solar System Dynamics. Archived from the original on 7 July 2021. Retrieved 14 August 2023.
- ^ a b "Latest Published Data". The International Astronomical Union Minor Planet Center. Archived from the original on 5 March 2019. Retrieved 14 August 2023.
- ^ Mumma, M. J.; Disanti, M. A.; Dello Russo, N.; Magee-Sauer, K.; Gibb, E.; Novak, R. (2003). "Remote infrared observations of parent volatiles in comets: A window on the early solar system". Advances in Space Research. 31 (12): 2563–2575. Bibcode:2003AdSpR..31.2563M. CiteSeerX 10.1.1.575.5091. doi:10.1016/S0273-1177(03)00578-7.
- ^ "IAU Office of Astronomy for Education". IAU Office of Astronomy for Education. Retrieved 11 December 2023.