Every scrap of matter in our solar system originated as part of a giant interstellar cloud. As it grew hot and dense, gravity began to pull dust and gas inwards.

Gravity sculpted this material into the planets, as well as smaller bodies such as asteroids, comets and meteoroids. Some of these objects are still tumbling through interstellar space today.

The Sun

The Sun and the entire solar system orbits around the center of our Milky Way galaxy.

The average speed is 828,000 km/hr or 448,000 mph (716,000 km/h). It will take 230 million years for the solar system to complete one full orbit.

The hottest part of the Sun is its core, where hydrogen fuses to form helium through nuclear reactions. Temperatures here reach 27 million degF (15 million degC).

The Moon

The Moon is Earth’s natural satellite, orbiting us in an elliptical orbit. Over time, the Moon rocks a little from north to south and wobbles a bit from east to west.

These minor tidal effects aren’t enough to slow the Moon down as it moves through space. It will continue to orbit Earth for millions of years, unless something happens.

Mercury

Mercury is a tiny planet in the Solar System that takes about 59 Earth days to rotate on its axis. It orbits the Sun, and in the process it passes close to the Sun, thus causing some disturbances in its atmosphere and magnetic field.

The resulting effect appears as a gyration, or precession, of its orbital path. This motion, about 9.5′ (0.2deg) of arc per century, is a test of the general theory of relativity and is one of the most significant confirmations to date of this theory.

Venus

Venus is the second planet from the Sun and Earth’s closest planetary neighbor. It has a thick atmosphere dominated by carbon dioxide, though it does have a small percentage of nitrogen.

Unlike most other planets, Venus orbits the Sun clockwise on its axis. This is due to a collision in the early part of its life.

Earth

The Earth rotates on its axis and orbits the Sun. One rotation takes about 365 days, or one year.

Scientists have studied these motions to understand how the solar system moves through space. But it’s still unclear how the planets move relative to each other.

Mars

Mars, the fourth planet from the Sun, is a dry, rocky world. It’s also the closest planet to Earth and home to a new rover that’s searching for signs of past life.

Getting to Mars involves travelling through space using several different orbits and manoeuvres. One is called the Hohmann transfer, and it’s the most fuel-efficient way to travel between the two planets.

Jupiter

Jupiter’s fast rotation – it completes a single day in less than 10 hours – creates strong jet streams that separate the planet’s clouds into long bands of bright and dark material.

These jet streams reach depths of 2,000 miles (roughly 3,200 kilometers). They are similar to the jet streams that form on Earth, but at far higher latitudes.

Saturn

Saturn is the second-largest planet in our solar system. It is a gas giant made up of mostly hydrogen and helium.

A large percentage of its mass is in its liquid metallic core that lies deep inside the planet’s interior.

Like the other gas giants in our solar system, Saturn has a dense outer core of metals like iron and nickel. Then, a layer of liquid metallic hydrogen covers that.

Uranus

Uranus is an ice giant and one of the outer planets in the solar system. It receives 360 times less light and heat from the Sun than Earth.

It has an extensive satellite system, including several moons. The largest of these are Oberon and Titania.

Neptune

The Solar System is an assemblage of eight planets, many asteroids, and a vast reach of highly tenuous gas and dust known as the interplanetary medium.

The Sun influences the motion of all these bodies, which orbit it in elliptical orbits.

Neptune is a blue gas giant, the eighth planet from the Sun. It has a rocky core, and its surface is covered with a thick atmosphere.