The Sun
The central star of our planetary system and the dominant source of energy that drives many processes throughout the system.
A journey through the Sun, planets, moons, asteroids, comets and the vast structures that make up our cosmic home.
Begin ExplorationOur Solar System is the planetary system centered on the Sun. It contains the Sun, planets, dwarf planets, moons and many smaller bodies that are held in orbit by gravity.
The central star of our planetary system and the dominant source of energy that drives many processes throughout the system.
Four rocky terrestrial planets occupy the inner Solar System, while four giant planets orbit farther from the Sun.
Dwarf planets, moons, asteroids, comets and other small bodies preserve important clues about Solar System history.
The Solar System is located in the Milky Way galaxy. Our Sun orbits the center of the galaxy and takes roughly 230 million years to complete one galactic orbit.
The Sun is a star and the gravitational center of our Solar System. Its enormous mass governs the motion of planets and other objects around it.
Deep inside the Sun, extremely high temperature and pressure allow nuclear fusion to occur. Hydrogen nuclei combine to form helium and release energy.
That energy eventually travels outward and reaches space as electromagnetic radiation, including the sunlight that warms Earth.
Explore the core, radiative zone, convection zone, photosphere, chromosphere and corona.
Learn about sunspots, solar flares, prominences and coronal mass ejections.
Discover the continuous flow of charged particles moving outward from the Sun.
From the small rocky world Mercury to the distant ice giant Neptune, each planet represents a different chapter in the evolution of our planetary system.
The smallest planet and the closest planet to the Sun.
A rocky world with a thick atmosphere and an extreme greenhouse effect.
Our home world, with abundant liquid water and the only confirmed life known to science.
The red planet, with a cold desert surface and evidence of a watery past.
The largest planet in the Solar System, famous for its enormous storms and powerful magnetic environment.
A giant planet surrounded by a spectacular system of icy and rocky rings.
An ice giant with a dramatic axial tilt, giving it one of the strangest seasonal cycles in the Solar System.
The most distant recognized planet, with a dynamic atmosphere and powerful winds.
These worlds are large enough for gravity to shape them into approximately round bodies, but they have not cleared their orbital neighborhoods.
The only officially recognized dwarf planet in the inner Solar System and the largest object in the main asteroid belt.
A distant dwarf planet in the Kuiper Belt with a complex system of moons.
A rapidly rotating dwarf planet with an unusual elongated shape.
A distant icy world and one of the major known dwarf planets of the Kuiper Belt.
A distant dwarf planet whose discovery played an important role in the debate over the definition of a planet.
Moons are natural satellites that orbit planets, dwarf planets and, in some cases, smaller bodies. They range from tiny irregular objects to worlds with complex geology and atmospheres.
Our Moon is Earth's natural satellite and has played an important role in understanding planetary formation, tides and the history of space exploration.
Some moons are believed to contain oceans beneath their icy surfaces, making them important targets for planetary science.
Jupiter, Saturn, Uranus and Neptune possess diverse moon systems that act like miniature planetary laboratories.
Not every piece of material in the young Solar System became a planet. Many remnants remain today and provide clues about the conditions that existed billions of years ago.
Rocky or metallic bodies that orbit the Sun. Many are found in the main asteroid belt between Mars and Jupiter.
Icy bodies that can develop bright comae and tails when solar heating causes material to escape from their surfaces.
Small fragments of rock or metal traveling through space. When they enter an atmosphere and produce a visible streak, the phenomenon is called a meteor.
Pieces of extraterrestrial material that survive passage through an atmosphere and reach the ground.
Beyond Neptune lies a vast region of icy objects and distant structures. The Solar System extends much farther than the orbit of the most distant planet.
A broad, disk-like region beginning around Neptune's orbit and containing many icy bodies and dwarf planets.
~30–50 AUA more extended population of trans-Neptunian objects whose orbits can carry them much farther from the Sun.
Beyond Kuiper BeltA theorized, enormous spherical shell of distant icy bodies surrounding the Solar System. It has not been directly observed.
Thousands–100,000 AUThe Sun continuously releases a stream of charged particles called solar wind. The region dominated by this solar wind is known as the heliosphere.
The Solar System was not created instantly. It developed through a long sequence of gravitational collapse, accretion, collisions and planetary evolution.
A dense region of interstellar gas and dust began collapsing under gravity.
The collapsing material flattened into a rotating disk surrounding the forming Sun.
Dust and rocky particles collided and accumulated into larger bodies called planetesimals.
Growing bodies eventually became planets, dwarf planets and moons while leftover material remained as smaller bodies.
The Solar System continues to evolve. Scientists study its present structure to understand its ancient history.
Approximate age of the Solar System.
Spacecraft have transformed our understanding of the Solar System by flying past planets, entering orbit, landing on worlds and studying distant objects.
Explore Space Missions