Question

Imagine that charged particles interacted with magnetic fields in such a way as to be able to cross the field lines but not move along them. Would there be any auroral displays – borealis, australis, or otherwise? Justify your answers.

Answer 1

Answer :-

• What are Northern light (‘Aurora borealia’ & ‘Aurora Australia’)

The bright dancing lights of the aurora are actually , collision between electrically, charged particles from the sun that enter the earth atmosphere The light are seen above the magnetic poles of the northern and southern hemisphere they are known as’ Aurora borealia’ in the north. And ‘Aurora Australia’ in the south.

Aurora displays appear in many colour although pale green and pink are the most common shades of red , yellow,green,blue and violet have been reported . The light 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.

• What causes the Aurora borealis and Aurora Australia light ?

The northern light are actually the result of collision between gaseous particle in the earth. Atmosphere with charged particle released from the sun atmosphere rarration in colour are due to type of gas particles that are colliding. The most common auroral coloured a pale yellowish colour green is produced by oxygen molecule located at 60 miles above the earth. Rare all red auroras are produced by high altitude oxygen at height of up to 200 miles . nitrogen produces blue or purplish red aurora.

The temperature above the surface of the sun is millions of degree. Celcius at this temperature collision between gas molecule are frequent and explosive free electron and proton are thrown from the the suns 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 particle are largely deflected by the earth magnetic field. However the earth magnetic fiels is weaker at either pole and therefore same particles enter the earths atmosphere and collide with gas particles. These collision emit light that we preceives as the dancing light of the north.(and the south)

The light of the aurora generally extend from 80km(50 miles) to as high as 640km(400miles) above the earth surface.

• Where is the best place to watch the Northern light?

Northern lights can be seen in the northern or southern hemisphere , in an irregularly shaped oval centred over each magnetic pole. The light are known s Aurora borealis in the north and Aurora austral is in the south . Scientist have learned that in most instances northern and southern auroras are mirror like images that occurs at the same time with similar shapes and colours.

               Because the phenomena occurs near the magnetic poles, northern lights have been seen as far south as New Orleans in the western hemisphere, while similar locations in the east never experience the mysterious lights. However the best places to watch the lights (in North America) are in the north-western parts of Canada, particularly the Yukon, Nunavut, Northwest Territories and Alaska. Auroral displays can also be seen over the southern tip of Greenland and Iceland, the northern coast of Norway and over the coastal waters north of Siberia. Southern auroras are not often seen as they are concentrated in a ring around Antarctica and the southern Indian Ocean. Areas that are not subject to 'light pollution' are the best places to watch for the lights. Areas in the north, in smaller communities, tend to be best.

• When is the best time to watch for Auroral Displys?

Researchers have also discovered that auroral activity is cyclic, peaking roughly every 11 years. The next peak period is 2013.

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 (adjust for differences caused by daylight savings time).