The Northern Lights, or Aurora Borealis, are caused by interactions between the Earth's magnetic field and particles from the Sun. When solar storms eject electrons and protons from the Sun's surface, they travel through space and enter the Earth's atmosphere near the magnetic poles. There, the particles excite oxygen and nitrogen atoms in the atmosphere, causing them to glow in colorful patterns of light known as the Northern Lights. The size and shape of the Aurora is determined by the level of activity on the Sun - more active periods result in a larger and more extended light display.

1. The Aurora Borealis Click Mouse to advance Composer: Carl Orff ,in the year 1936 Perormed by : The Boston Symphany Orchestra MUSIC BY: Carmina Burana

15. Since the World began, Solar Lights have been an Integral part of our planet Earth. They do not depend at all on the human activity, but rather on that of the Sun and the terrestrial magnetic field. The Dawn is not as one once believed (until some 70 years ago), that causes the reflection of solar light on the ices of the Arctic. However, it is indeed the Sun, which is responsible for the Polar Lights as the turbulent surface of the Sun rejects into the space the atoms and the subatomic particles (protons, electrons). At the time of violent solar storms, a great quantity of electrons and protons coming from the Sun arrive in the terrestrial atmosphere and activate the nitrogen and oxygen atoms, which become suddenly luminous and produce the splendid veils (ribbons or curtains) of coloured light, which are the polar lights. They are named Polar because once arrived in the terrestrial atmosphere, the particles are taken by the trap of the magnetic field, which forces them to move towards the magnetic poles either north (Northern Lights) or in the south (Aurora Australis) Dawn with the shape of a thin elliptic band (the auroral oval) is centred on the magnetic north and south poles, i.e. approximately within 700 meters of the geographical poles. The size of this form depends on the solar activity: the more the Sun is quiet" and the solar wind calm the oval is smaller; conversely the more the solar wind strikes the terrestrial magnetic field with force and gusto, more the dawn becomes broad and extends . A urore North & South

23. The Affect of the Solar atmosphere The temperature of the solar atmosphere is several million degrees Kelvin (temperature °C = temperature °K - 273,15). At these temperatures, the collisions between the particles are so violent that the hydrogen atoms break up into electrons and protons. This “material" is called ionized plasma. The Solar wind is when this plasma moves away from the sun in all the directions. transports the Solar Magnetic Field into interplanetary space. The speed and the density of this solar wind vary greatly. They are larger when the wind comes from the active areas of the sun, like the solar spots or protuberances.

28. The End