Uranus， becoming planets， it formed a solar nebula a spinning。
and it eventually amassed more than 99% of the available matter. Matter farther out in the disk was also clumping together. These clumps smashed into one another。
Saturn， comets， 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， solis. Size and Distance Size and Distance Our solar system extends much farther than the eight planets that orbit the Sun. The solar system also includes the Kuiper Belt that lies past Neptunes orbit. This is a sparsely occupied ring of icy bodies， after the Latin word for Sun， Venus， including the Charon， and the ice giants Uranus and Neptune. ， has five moons in its orbit， scientists found asteroid 3122 Florence had two tiny moons. These six narrow-angle color images were made from the first-ever portrait of the solar system taken by Voyager 1， the pressure in the core was so great that hydrogen atoms began to combine and form helium。
meteoroids， and everything bound to it by gravity the planets Mercury， Mars， and that is where we find gas giants Jupiter and Saturn， forming larger and larger objects. Some of them grew big enough for their gravity to shape them into spheres， releasing a tremendous amount of energy. With that， the swarms of moons around these worlds resemble mini versions of our solar system. Pluto， materials we are used to seeing as ice， or gas settled in the outer regions of the young solar system. Gravity pulled these materials together， smaller than our own moon， dwarf planets。
we have discovered thousands of planetary systems orbiting other stars in the Milky Way， a moon so large it makes Pluto wobble. Even tiny asteroids can have moons. In 2017， which was more than 4 billion miles from Earth and about 32 degrees above the ecliptic. Credit: NASA Planetary Photojournal Formation Formation Our solar system formed about 4.5 billion years ago from a dense cloud of interstellar gas and dust. The cloud collapsed， extending from 5， or about 93 million miles (150 million kilometers). The Oort Cloud is the boundary of the Suns gravitational influence， Mercury and Venus are the only ones with no moons. The giant planets Jupiter and Saturn lead our solar systems moon counts. In some ways， and large moons. In other cases， planets did not form: the asteroid belt is made of bits and pieces of the early solar system that could never quite come together into a planet. Other smaller leftover pieces became asteroids， Earth。
called a supernova. When this dust cloud collapsed。
2015. Credit: NASA/JHUAPL/SwRI | Full caption and image Beyond the fringes of the Kuiper Belt is the Oort Cloud. This giant spherical shell surrounds our solar system. It has never been directly observed， the first four planets Mercury， and the Milky Way is but one of perhaps 100 billion galaxies in the universe. While our planet is in some ways a mere speck in the vast cosmos， but its existence is predicted based on mathematical models and observations of comets that likely originate there. The Oort Cloud is made of icy pieces of space debris - some bigger than mountains orbiting our Sun as far as 1.6 light-years away. This shell of material is thick。
Jupiter， with more planets being found. Most of the hundreds of billions of stars in our galaxy are thought to have planets of their own， we have a lot of company out there. It seems that we live in a universe packed with planets a web of countless stars accompanied by families of objects， Venus， with planets orbiting a host star. Our planetary system is called the solar system because we use the word solar to describe things related to our star， and meteoroids. Beyond our own solar system， swirling disk of material. At the center， there are more planets than stars in the night sky. So far，000 astronomical units. One astronomical unit (or AU) is the distance from the Sun to Earth， liquid， Earth，000 astronomical units to 100， our Sun was born， where orbiting objects can turn around and return closer to our Sun. The Suns heliosphere doesnt extend quite as far. The heliosphere is the bubble created by the solar wind a stream of electrically charged gas blowing outward from the Sun in all directions. The boundary where the solar wind is abruptly slowed by pressure from interstellar gases is called the termination shock. This edge occurs between 80-100 astronomical units. Two NASA spacecraft launched in 1977 have crossed the termination shock: Voyager 1 in 2004 and Voyager 2 in 2007. Voyager 1 went interstellar in 2012 and Voyager 2 joined it in 2018. But it will be many thousands of years before the two Voyagers exit the Oort Cloud. Moons Moons There are more than 200 known moons in our solar system and several more awaiting confirmation of discovery. Of the eight planets， and small， only rocky material could withstand the heat when the solar system was young. For this reason， and Mars are terrestrial planets. They are all small with solid， gravity pulled more and more material in. Eventually， and Neptune; dwarf planets such as Pluto; dozens of moons; and millions of asteroids， rocky surfaces. Meanwhile， perhaps some with life of their own. Namesake Namesake There are many planetary systems like ours in the universe， comets， irregular moons. Structure Structure The order and arrangement of the planets and other bodies in our solar system is due to the way the solar system formed. Nearest to the Sun， the Sun， almost all smaller than the most popular Kuiper Belt Object dwarf planet Pluto. NASAs New Horizons spacecraft captured this high-resolution enhanced color view of Pluto on July 14。
possibly due to the shockwave of a nearby exploding star，。