BBA (HONs) student (space)

Okay, today too we will talk about sun…. what so special about sun…. sun is a star that gives us light for us precede our life. Now, I want to talk about phenomena that happen at sun… A halo is an optical phenomenon produced by ice crystals creating a single ring of color around the sun or moon. It occurs more frequently than a rainbow. They are produced by the ice crystals in cirrus clouds high (5–10 km, or 3-6 miles) in the upper troposphere. The shape and orientation of the crystals is responsible for the type of halo observed. Six-sided ice crystal that make up those clouds act as the prisms that separate the sun's light into colors. The light is reflected and refracted by the ice crystals and split up into colors by dispersion. The crystals behave like prisms and mirrors, refracting and reflecting sunlight between their faces, sending shafts of light in particular directions. Atmospheric phenomena such as halos were used as part of weather lore as an empirical means of weather forecasting before meteorology was developed. To see a halo, don't look directly into the sun. Instead, block the sun from your view with your hand, so you can just see the clouds around it.

Sunglasses also may help you see a halo but even with sunglasses, you'll need to block the sun from your eyes.

Next, I want to talk about Aurora Borealis or known also as Northern Light…. Aurora Borealis is bright dancing lights of the aurora are actually collisions between electrically charged particles from the sun that enter the earth's atmosphere. The lights are seen above the magnetic poles of the northern and southern hemispheres. They are known as 'Aurora borealis' in the north and 'Aurora australis' in the south. Aurora displays appear in many colors 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.

Then, what the cause for Aurora Borealis? Aurora Borealis are actually the result of collisions between gaseous particles in the Earth's atmosphere with charged particles released from the sun's atmosphere. Variations in color are due to the type of gas particles that are colliding. The most common aurora 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.

Because the phenomena occur 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 northwestern parts of Canada, particularly the Yukon, Nunavut, Northwest Territories and Alaska. Aurora 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.