1. Read the following passage and make notes in an appropriate format: (15) The Northern Lights are actually the result of collisions between gaseous particles in the Earth's atmosphere with charged particles released from the sun's atmosphere. Auroral displays appear in many colours although pale green and pink are the most common. Shades of red, yellow, green, blue, and violet have been reported. The lights appear in many forms from patches or scattered clouds of light to streamers, arcs, rippling curtains or shooting rays that light up the sky with an eerie glow. The most common auroral color, a pale yellowish-green, is produced by oxygen molecules located about 60 miles above the earth. Rare, all-red auroras are produced by high-altitude oxygen, at heights of up to 200 miles. Nitrogen produces blue or purplish-red aurora. The connection between the Northern Lights and sunspot activity has been suspected since about 1880. Thanks to research conducted since the 1950's, we now know that electrons and protons from the sun are blown towards the earth on the 'solar wind'. The temperature above the surface of the sun is millions of degrees Celsius. At this temperature, collisions between gas molecules are frequent and explosive. Free electrons and protons are thrown from the sun's atmosphere by the rotation of the sun and escape through holes in the magnetic field. Blown towards the earth by the solar wind, the charged particles are largely deflected by the earth's magnetic field. However, the earth's magnetic field is weaker at either pole and therefore some particles enter the earth's atmosphere and collide with gas particles. These collisions emit light that we perceive as the dancing lights of the north (and the south). Northern Lights can be seen in the northern or southern hemisphere, in an irregularly shaped oval centred over each magnetic pole. The lights are known as 'Aurora borealis' in the north and 'Aurora australis' in the south. Scientists have learned that in most instances northern and southern auroras are mirror-like images that occur at the same time, with similar shapes and colors. Winter in the north is generally a good season to view lights. The long periods of darkness and the frequency of clear nights provide many good opportunities to watch the auroral displays. Usually the best time of night (on clear nights) to watch for auroral displays is local midnight. Many cultural groups have legends about the lights. In medieval times, the occurrences of auroral displays were seen as harbingers of war or famine. The Maori of New Zealand shared a belief with many northern people of Europe and North America that the lights were reflections from torches or campfires.The Menominee Indians of Wisconsin believed that the lights indicated the location of manabai'wok (giants) who were the spirits of great hunters and fishermen. The Inuit of Alaska believed that the lights were the spirits of the animals they hunted: the seals, salmon, deer and beluga whales. Other aboriginal peoples believed that the lights were the spirits of their people.
Answers
Title: Northern Lights/Aurora Borealis and Aurora Australis
Notes:
I. Cause, colors and shape
1. Collison betw gaseous partcls from earth and sun
2. pale green, pink, shades of red, yellow, green, blue, and violet
3. clouds of light, streamers, arcs, rippling curtains, shooting rays
II. Location
1.60 and 200 miles above earth
2. North and South Poles
III. Research Facts
1.Free electrn and protn form the sun
2. Deflctn by earth’s mgntc filed
3. Weak mgntc field at poles
4. Collision emits light
IV Best Time to See
1.Winter in the north
2.Local midnight time
5.Myths about Lights
1.Reflection of camp-light and torches
(believed by Maoris, people from North Euro and North America)
2. Menominee Indians believed spirits of hunters
3.Inuit believed spirits of hunted animals
4.Oboriginals believed spirits of ancestors.
Key to Abbreviation
Betw = between
Partcls = particles
Electrn = electron
Protn = proton
Deflctn = deflection
mgntc = magnetic