SUN

THE SUN	· Your travel guide to the Solar System ·
	DEFINITION The Sun is a star at the centre of the Solar System. All the planets revolve around it. REASONS TO VISIT The surface of this burning ball of gas is 5500ºC, with the core reaching a sweltering 15.6 million ºC The Sun is so large, you could fit over one million Earths inside it		Solar System Jigsaw Can you build the Solar System?

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WHAT TO SEE The Sun is a 1 million km wide ball of burning gas. So be prepared for the best firework show you have ever seen! Solar flares Variations in the Sun's magnetic field cause huge jets or loops of stellar material to shoot out into space. Solar wind Solar flares can be accompanied by dense clouds of electrically charged particles, travelling at around 450km per second. When they reach Earth, they can affect communications satellites. But make sure you wear your protective sun filters over your eyes otherwise you could damage your eyesight. FROM THE EARTH The Sun is by far the brightest object in the sky. It's so bright that during the day its light drowns out virtually everything else in space. The Sun is so powerful that even from the Earth, its light can damage your eyesight. So never look at the Sun directly or through a telescope. The best time to appreciate the majesty of the Sun from the Earth is during a solar eclipse. Then the Moon passes in front of the Sun and so it temporarily disappears from the sky. INSIDE THE SUN Life on Earth is totally dependent on the the energy it receives from the Sun. This energy is produced when hydrogen atoms inside the Sun fuse to form helium. The Sun consumes four million tons of hydrogen every second. Even so, it's so vast that our star has enough fuel to keep it shining for another five billion years. The Sun's energy output is estimated to be 386 billion, billion megawatts. So in 15 minutes our Sun radiates as much energy as mankind consumes in all forms, during an entire year.

TRAVEL INFORMATION Before you leave Make sure you obtain a timetable of sunspot activity. Sunspots are caused when the Sun's gasses are disrupted as they spin around. Why sunspots happen Just like the Earth and all the planets, the Sun spins around a central axis. But this rotation is not smooth like the Earth because the Sun is not solid. So the gas at the Sun's poles revolves at a different speed to the gas at the equator. This causes the Sun's magnetic field to warp. Magnetic eruptions manifest themselves as dark 'sunspots' on the surface. Eventually the field becomes so complex that it collapses, causing the north and south poles to swap. Then the process begins again. This is known as the 'solar cycle'. A complete cycle takes 22 years, after which the original north pole is restored. Maximum sunspot activity occurs during the period when the poles are in the process of switching. The last time this happened was in 2001. When you arrive A journey to the Sun itself would be impossible even for the best protected of ships due to the scorching temperatures. Anyone attempting to fly close to the Sun will have to be aware of the solar wind. It will have a significant effect on the path of any craft approaching the Sun. LOCAL HISTORY The Sun has been given many names over the course of history. The Greeks named it 'helios', the origin of the adjective 'heliocentric' (meaning centred around the Sun). The Romans referred to the Sun as 'sol'. Until the Middle Ages it was generally assumed that the Sun orbited the Earth. In the 16th century, Nicholas Copernicus argued that it was the Earth that travelled around the Sun. However, he was not the first person to suggest this - the Greek Philosopher Aristarchus beat him to it by nearly 2000 years. Copernicus's view of the Solar System wasn't accepted for many years until Newton formulated his laws of motion.(www.bbc.co.uk)