What objects can be found in our solar system?

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Other Bodies in the Solar System
Besides the eight planets and their moons, there are many other objects in the solar system that are in orbit around the Sun. Head to ngscience.com for loads of additional resources on the world's most comprehensive dedicated science platform for schools.

Comets are orbiting bodies comprised of frozen gases, rock, ice and dust. When a comet passes close to the Sun, heat causes it to release gases. This forms a tail of gases called a coma. The size of most comets ranges from around 700 meters to 20 kilometers.

The Hale-Bopp comet was discovered separately by the astronomers Alan Hale and Thomas Bopp on July 23, 1995. In 1997, the Hale-Bopp comet became visible to the naked eye on Earth for a record 18 months. It will return to the inner solar system around the year 4385.

Halley’s Comet takes about 76 years to complete an orbit of the Sun. It was last seen by the naked eye from Earth in 1986 and will be visible from Earth again in the year 2061.

One of the most commonly found objects in space are asteroids. Asteroids are large rocks orbiting the Sun. They range in size from just a few meters up to hundreds of kilometers. Most asteroids orbit the Sun in an asteroid belt between the planets Mars and Jupiter.

The largest asteroid observed in the asteroid belt is Ceres, which is also classified as a dwarf planet. It has a diameter of 940 kilometers (580 miles).

Asteroids and comets often break up into smaller pieces and form meteoroids. Meteoroids have a size ranging from a grain of sand to one meter. If a meteoroid enters Earth’s atmosphere, it becomes known as a meteor. Most meteors burn up completely before reaching the Earth’s surface. The shooting stars we see at night are most likely meteors burning up in the Earth’s atmosphere.

Occasionally, a meteor doesn’t burn up completely as it enters the atmosphere. A meteor that reaches the Earth’s surface is called a meteorite.

The Solar System
A satellite is any object that orbits a central star or planet. In our solar system, the Sun is the central star. The satellites orbiting the Sun include the eight planets, their moons and other objects such as comets, asteroids and man-made objects.

The largest satellites in our solar system are the eight planets. In order of their distance from the Sun, the four closest planets are Mercury, Venus, Earth and Mars. These planets are called the inner planets or terrestrial planets. They are made up mostly of rock and are similar in size to the Earth. Due to their close distance to the Sun, the inner planets are also much warmer than the planets further from the Sun.

The outer planets are the four furthest planets from the Sun – Jupiter, Saturn, Uranus and Neptune. These planets are much larger than the inner planets and are not rocky. Jupiter and Saturn are made up mostly of gases such as hydrogen and helium and have dense atmospheres. They are called gas giants. Uranus and Neptune are made up of heavier substances referred to as ‘ices’ and are classified together as ice giants.

Artificial Objects in the Solar System
Like the planets and their moons, comets, asteroids and meteoroids are natural satellites. There are also many artificial satellites orbiting the Sun. An artificial satellite is a man-made object that is launched into space by people and enters the orbit of a body in space. Artificial satellites can orbit the Sun, Earth, other planets or moons.

Communication satellites are artificial satellites that are used to receive and send data to and from the Earth. They can be used for weather forecasting, sending digital signals and can provide us with accurate information about locations on Earth.

Some artificial satellites are used to observe and gather data about other objects in the solar system, such as planets, moons and the Sun. Space telescopes are man-made satellites in space. They enable astronomers to see things further away than most telescopes on Earth.

One of the largest space telescopes is the Hubble Space Telescope. It was launched into low Earth orbit in 1990 and has allowed astronomers to gather high resolution images of deep space. The Hubble Space telescope is scheduled to be succeeded by the James Webb Space Telescope (JWST) in 2021. The JWST is a joint collaboration between the space agencies of the USA, Europe and Canada. The JWST is much larger than Hubble and will be used to observe much deeper into space.

People often go on missions aboard spacecrafts launched into space by powerful rockets. Some people spend extended periods of time in space living in space stations such as the International Space Station (ISS). The ISS is the largest man-made object in space.