Gas Giants

Gas Giants

The gas giants are the four planets in the Solar System furthest from the Sun. They are mainly massive balls of swirling gases, although some of them may have rocky cores at the centre.
Like all the planets, the gas giants do not make their own light. They shine by reflecting light from the Sun. However, if the biggest planet, Jupiter, had been about 50 times larger when it formed, it would have been a star. Saturn is the second biggest planet and famous for its many beautiful rings. The outermost planet, Neptune, is a vivid blue colour, and is named after the Roman god of the sea.

Jupiter and Saturn

More than 1,320 Earths would fit into Jupiter, also known as the King of the Planets. Jupiter spins around extremely fast - once every ten hours - and is surrounded by coloured stripes of different gases.

Saturn is famous for its rings. Its three main rings and several fainter rings are less than 50 metres (164 feet) thick, so they cannot be seen when edge-on to Earth. However, Saturn's main outer ring, called A, is more than 270,000 kilometres (167,770 miles) across.

Farther, colder, slower

Uranus and Neptune are so far from the Sun that they are incredibly cold. The surface of Neptune can fall below-200°C (-392°F), Both planets have thick gas layers and a bluish colour caused by the methane gas in their atmospheres. Massive storms also rage on the planets' surfaces.

The winds on Neptune are the fastest in the Solar System nearly 10 times more powerful than those on Earth. The planets furthest from the Sun move more slowly, and Neptune takes almost 165 years to travel around it.

Fact Brief

Fascinating Fact
• Gas giants are not all gas. There are layers of molecular hydrogen and liquid metallic hydrogen lying beneath the heavy atmospheres of Jupiter and Saturn. The metallic hydrogen layers conduct electricity.
• The Great Red Spot on Jupiter is one of its most familiar features. This persistent anticyclonic storm, which is located south of its equator, measures between 24,000 km in diameter and 12–14,000 km in height. As such, it is large enough to contain two or three planets the size of Earth’s diameter. And the spot has been around for at least 350 years, since it was spotted as far back as the 17th century.