“We must accept finite disappointment, but never lose infinite hope.”
These wise words from Martin Luther King Jr. sound celestial, and describe my attitude toward seeing the aurora borealis, or Northern Lights, from this latitude. Last week’s hyped opportunity was foiled by cloud cover, but increased my optimism for future views.
Though not an impossibility here, the auroras are more predictably seen further north and south. The light display is typically confined to the auroral ovals, the area from approximately three to six degrees latitude near the North and South Poles. In the southern hemisphere, this spectacular sky show is known as the aurora Australis or Southern Lights.
Auroras are color displays in the sky that begin at the sun. Solar wind, moving at speeds of one million miles an hour directly toward the earth, contains charged electrons that interact with the earth’s atmosphere. When these electrons hit the atmosphere, they move along the magnetosphere, an area of charged electrical and magnetic fields.
These electrons will eventually strike atoms of oxygen or nitrogen and releasevisible light. The color produced depends on which atom they collide with and at what altitude. Striking oxygen below 150 miles in altitude yields green, while above 150 miles will show red in the sky. Colliding with nitrogen atoms produce blue below 60 miles and violet/purple above 60 miles. The blending of colors can produce different shades and hues.
Earth is not the only planet that claims this celestial sight. All of the gas planets can have auroras, though the other planets only see red because oxygen is lacking in their atmospheres.
Bright lights and big cities make for conditions that would preclude seeing this heavenly show, since the light pollution blocks out the sky. Reportedly, states as far south as Pennsylvania had a chance to see the spectacle, though successful sightings were few and far between. The range of areas that can see the aurora borealis expands to lower latitudes when there is a lot of sunspot activity, which varies on an 11-year cycle. Auroras are also more likely to occur during the spring and fall, and are best seen late night between the hours of midnight and 2 a.m.
This phenomenon has been common throughout history. Its name has both Greek and Roman lineage. Aurora was the Roman goddess of the dawn and Boreas is the Greek name for the north wind. The Cree called the event the dance of the spirits, and in the Middle Ages it was thought to be a sign from God.
Indeed, “Who but God can conceive such infinite scenes of glory? Who but God could execute them, painting the heavens in such gorgeous displays?” asked an unknown author describing this divine event. I concur; for if God ever wanted to see His name up in lights, what could possibly top this?\
Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown.