Space for the Earthbound - A Journey Through the Universe

Explore the endlessly fascinating world of outer space from the comfort of your home

Tuesday

Aurora Borealis (the Northern Lights)

It makes no difference whether you call this incredible light display the Aurora Borealis or the Northern Lights - the show is still the same! A wispy, undulating canvas in the sky.

In 1621, Pierre Gassendi, a French astronomer, philosopher, mathematician and scientist, was the first to give a name to this "otherworldly" phenomenon. Aurora - for the Roman goddess of dawn, and Borealis - the name the Greeks gave to the North Wind, which they called Boreas.

Photo Credit: Senior Airman Joshua Strang, USAF

As the name implies, these light shows are seen in the Northern Hemisphere. The light shows seen below the equator are the Aurora Australis. These displays are also known as polar auroras, or aurorae. The closer you are to one of the poles, the better your chance of seeing this breathtaking spectacle. They are more apt to be seen around the time of the equinoxes, usually March 20th and September 22nd. As with viewing meteor showers, the best time to see the lights is at new moon. The less moon from the sky, the better view for your eye.

Here is a fantastic video display put together by a Youtube user, having over 70 pictures in a 3:12 display. There are some absolutely amazing photos in this collection. In two of the shots, meteor streaks can also be seen.
http://www.youtube.com/watch?v=7GThxWmmvvk&NR=1

The best places for seeing the Aurora Borealis are areas close to the northern pole; Alaska, Canada and Scandinavia. Sightings in the lower 48 states do occur, but not with near the frequency of those in higher latitudes. In one very extreme event during 1958, the Aurora Borealis was reported to be seen as far south as Mexico City.

Aurorae are typically a night event, with the best viewing in the 3 to 4 hours around the midnight hour, although they can be seen at all hours from dusk to dawn. Daytime viewing is extremely rare, except in Svalbard, an archipelago north of the European mainland in the Arctic Ocean. During the 2 and a half month period around the Winter Solstice, occurring December 21st or 22nd of each year for the Northern Hemisphere, Svalbard remains dark enough during the daytime that the auroral oval is easily seen overhead at the noon hour.

In what is believed to be the most spectacular auroral event in recent history, enough geomagnetically induced current was produced by an auroral storm in 1859 for two telegraph operators to carry on a conversation between Boston and Portland, Maine, for about two hours without the then required use of batteries. Recorded from the operator in Boston: "My current is very strong at times, and we can work better without the batteries, as the aurora seems to neutralize and augment our batteries alternately, making current too strong at times for our relay magnets. Suppose we work without batteries while we are affected by this trouble."

While our technology for land communications has drastically improved in the last 100+ years, being very close to this kind of electric power can still wreak havoc on electronics or battery operated appliances and gadgets. But in the end, the show is worth the price of admission.


For a scientifically detailed and concise description of Aurora go here.

Author Resource: Written by Starr Hendon

Share/Bookmark

No comments: