| Solar System | |
|---|---|
 True color collage of the Solar System's planets, moons and select asteroids. Distances not to scale, sizes are to scale. | |
|
Stars |
1 (Sun) |
|
Known planets |
8 (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune) |
|
Known dwarf planets |
Possibly several hundred; nine currently recognized by the IAU (Ceres, Pluto, Haumea, Makemake, Eris, Gonggong, Quaoar, Orcus, Sedna) |
|
Known natural satellites |
582 (285 planetary, 297 minor planetary) |
|
Known minor planets |
794,832 (as of 2024-9-30) |
|
Known comets |
3,743 (as of 2023-01) |
|
Identified rounded satellites |
19 |
|
Age |
4.603 billion years |
|
Location |
Local Interstellar Cloud, Local Bubble, Orion–Cygnus Arm, Milky Way celestial objects |
The Solar System is a gravitationally bound system of celestial objects with the Sun at its center. It consists of eight planets, their moons, dwarf planets, asteroids, comets, and other smaller objects that orbit the Sun. The planets, including Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune, vary in size, composition, and distance from the Sun. Surrounding the planets are various regions, such as the asteroid belt between Mars and Jupiter and the icy Kuiper belt beyond Neptune. The Solar System is approximately 4.6 billion years old, forming from a giant molecular cloud of gas and dust, and it spans about 287.46 billion kilometers, stretching to the outer edges of the Oort cloud.[1]
Structure and Composition[]
At the center of the Solar System lies the Sun, a G-type main-sequence star that provides light and heat to the planets. Orbiting the Sun are eight planets, divided into two categories:
- Terrestrial planets (rocky): Mercury, Venus, Earth, and Mars.
- Gas and ice giants: Jupiter, Saturn, Uranus, and Neptune.
In addition to these planets, the Solar System includes five officially recognized dwarf planets: Pluto, Eris, Haumea, Makemake, and Ceres. There are also countless small Solar System bodies, including asteroids in the main belt between Mars and Jupiter, Kuiper Belt objects beyond Neptune, and comets originating from the distant Oort Cloud.[2]
Planetary Orbits[]
The planets orbit the Sun in elliptical paths that lie roughly in the same plane, known as the ecliptic plane. These orbits are governed by gravitational interactions, primarily with the Sun but also with each other. Most planets rotate on their axes in the same direction as their orbits (prograde rotation), with the exceptions of Venus and Uranus.[3]
Formation and Evolution[]
The Solar System formed from the remnants of an ancient molecular cloud that collapsed under its own gravity. A rotating disk of gas and dust formed around the newly ignited Sun, from which the planets coalesced. The inner Solar System, where temperatures were higher, produced rocky planets, while the outer Solar System formed larger bodies from ice and gas.[4]
Dynamical interactions, such as planetary migration and scattering, likely played a key role in shaping the system’s current configuration. One major event in early history was the Late Heavy Bombardment, a period of intense asteroid impacts about 4 billion years ago.[5]
Moons and Rings[]
Most major planets have natural satellites or moons, with Jupiter and Saturn having the largest numbers. Some moons, like Jupiter's Ganymede and Saturn's Titan, are larger than the planet Mercury. Gas giants also possess complex ring systems, the most prominent being Saturn’s.[6]
Exploration[]
The Solar System has been extensively explored by telescopes and robotic spacecraft. Missions such as Voyager 1 and 2, Cassini, New Horizons, and Mars rovers have greatly expanded our understanding of its structure, composition, and history. Human exploration has so far been limited to the Moon, although there are future plans for manned missions to Mars and beyond.[7]
Location in the Galaxy[]
The Solar System resides in the Orion Arm of the Milky Way galaxy, approximately 27,000 light-years from the galactic center. It takes about 225–250 million years for the Solar System to complete one orbit around the Milky Way.[8]
References[]
- ↑ https://science.nasa.gov/solar-system/solar-system-facts/
- ↑ https://lowell.edu/deep-space-spotlight-the-dwarf-planets-of-our-solar-system/#:~:text=Photo:%20A%20color%2Denhanced%20photo,scattered%20throughout%20our%20solar%20system.&text=A%20fancier%20term%20for%20this%20concept%20is%20%E2%80%9Chydrostatic%20equilibrium%E2%80%9D!
- ↑ https://public.nrao.edu/ask/why-do-the-planets-orbit-in-a-plane-parallel-to-the-spin-axis-of-the-sun/#:~:text=of%20the%20Sun?-,Why%20Do%20the%20Planets%20Orbit%20in%20a%20Plane%20Parallel,Spin%20Axis%20of%20the%20Sun?&text=Answer:%20First%2C%20let%20me%20answer,rest%20of%20the%20solar%20system.
- ↑ https://www.amnh.org/exhibitions/permanent/the-universe/planets/formation-of-our-solar-system
- ↑ https://science.nasa.gov/moon/lunar-craters/what-is-the-late-heavy-bombardment/
- ↑ https://science.nasa.gov/saturn/moons/titan/facts/
- ↑ https://science.nasa.gov/solar-system/solar-system-facts/
- ↑ https://science.nasa.gov/solar-system/