The planetary system we call home is located in an outer spiral arm of the Milky Way galaxy. Our solar system consists of our star, the Sun, and everything bound to it by gravity the planets Mercury,.

NASAs real-time science encyclopedia of deep space exploration. Our scientists and far-ranging robots explore the wild frontiers of our solar system.

In the outer solar system, the gas giants Jupiter and Saturn and the ice giants Uranus and Neptune have dozens of moons. As these planets grew in the early solar system, they were able to capture smaller.

Understanding the Context

Jupiter is the fifth planet from the Sun, and the largest in the solar system more than twice as massive as the other planets combined.

Mars is the fourth planet from the Sun, and the seventh largest. Its the only planet we know of inhabited entirely by robots.

In Depth The Kuiper Belt is a large region in the cold, outer reaches of our solar system beyond the orbit of Neptune. It's sometimes called the "third zone" of the solar system. Astronomers think there are.

Pluto was once our solar system's ninth planet, but has been reclassified as a dwarf planet. It's located in the Kuiper Belt.

Key Insights

The Sun is the star at the heart of our solar system. Its gravity holds the solar system together, keeping everything from the biggest planets to the smallest bits of debris in its orbit.

The Oort Cloud probably contains 0.1 to 2 trillion icy bodies in solar orbit. Occasionally, giant molecular clouds, stars passing nearby, or tidal interactions with the Milky Ways disc disturb the orbit of one of.

The brightest and largest object in our night sky, the Moon makes Earth a more livable planet by moderating our home planet's wobble on its axis, leading to a relatively stable climate. It also causes.