The Solar System
The solar system is a gravitationally bound system of the Sun, eight planets, dwarf planets, and many moons, asteroids, comets and meteoroids. It is located in the Milky Way galaxy.
Sun:
- The central star of the solar system.
- Provides energy and gravity for the system.
- Type: G2 main-sequence star, a yellow dwarf.
Planets:
- Inner Planets (Terrestrial):
- Mercury (closest to the Sun)
- Venus
- Earth (inhabited by humans)
- Mars
- Outer Planets (Gas Giants):
- Jupiter
- Saturn
- Uranus
- Neptune
Dwarf Planets:
- Objects smaller than planets but larger than asteroids.
- Includes Pluto, Ceres, Haumea, Makemake, Eris, and others.
Moons:
- Natural satellites orbiting planets.
- Notable examples include:
- Luna (Moon) - Earth's only moon
- Phobos and Deimos - Mars' moons
- Io, Europa, Ganymede, Callisto - Jupiter's moons
- Titan - Saturn's largest moon
Asteroids:
- Small rocky or metallic bodies.
- Found primarily in the asteroid belt between Mars and Jupiter.
Comets:
- Icy bodies that form long, glowing tails when approaching the Sun.
- Known to contain water, methane, and other organic compounds.
Meteoroids, Meteors, and Meteorites:
- Meteoroids: Small pieces of interplanetary debris.
- Meteors: Meteoroids that enter Earth's atmosphere and become visible as "shooting stars."
- Meteorites: Meteoroids that survive their passage through the atmosphere and reach the Earth's surface.
Formation of the Solar System:
- The solar system is believed to have formed about 4.6 billion years ago from a rotating cloud of gas and dust called the solar nebula.
- The Sun formed at the center of the nebula, while the remaining material coalesced into planets, moons, and other objects.
Characteristics:
- The solar system is approximately 28,000 light-years from the center of the Milky Way galaxy.
- It is located in the Orion Arm, a spiral arm of the galaxy.
- The average distance from the Sun to Earth is called one astronomical unit (AU), which is approximately 150 million kilometers.
- The solar system is relatively young compared to other celestial objects, having formed only a fraction of the universe's 13.8 billion-year history.