Imagine a curtain of shimmering colors hanging in the inky night sky. The hues of the curtain range from pale green, and soft yellow, to a royal purple; or if you are lucky a brilliant scarlet. If you live in or visit an "aurora belt" area you wouldn't have to imagine it. This beautiful sight would be yours to enjoy. What you would be seeing would be the aurora. But what causes this light show? And what do auroras have to do with the Sun?

There are two things surrounding the Earth that we can't see. The first is our atmosphere. Our atmosphere is several layers of gases that surround the Earth. The second is a giant magnetic field. Our Earth's core is made up of metals which act like a giant magnet in the center of the Earth. This creates a magnetic field around the Earth called the magnetosphere. The Earth's magnetosphere extends far into space.

Charged particles in space that get near the Earth's magnetic field can get pulled in and trapped in the atmosphere. Once they are trapped, the particles travel down the magnetic field's lines toward the Earth's magnetic poles. At the poles the particles hit the gases in the Earth's atmosphere. These collisions give off energy mainly in the form of heat, but we also see these collisions in the form of colored light. For auroras to happen, particles must be trapped by the Earth's magnetosphere. The particles come from charged particles that leave the Sun. It takes around two days for the particles to reach Earth. The amount of particles that leave the Sun depends on how active the Sun is. Signs of solar activity include Sunspots and solar flares. The more active the Sun is the more Auroras we have on Earth.

The best time to see the Aurora is during the Spring and Fall: more specifically in September and March, but scientists don't know why this is. During these times the aurora are very intense and can be seen from greater distances. The best time of day to see the aurora is during the night between midnight and 2 a.m. when the aurora are most active. The aurora goes through cycles. It first appears, then spreads out and develops wrinkles or waves, intensifies in color and begins to waver, after it intensifies it spreads out over a space of 1,000 miles or more and diffuses to a dull glow. About 20 minutes later this process begins again. This sequence occurs 2 or more times a night and takes several hours to complete.

The colors of the Aurora are caused by gases in the Earth's atmosphere. These gases, much like those in neon signs, collide with the charged particles of the aurora and produce colored light. Nitrogen causes red and blue aurora, Hydrogen causes red aurora, and oxygen causes the blue and green colors. Since there is quite a bit of oxygen in the Earth's atmosphere most aurora are a greenish blue color. The Aurora, like a neon sign, needs a power supply to trigger the electrical discharge process that leads to the emission of light. The source of energy for the aurora is the Sun.

Most people only see auroras at night because their glowing stands out against a darker sky. Scientists used to assume that the Auroral lights are like stars that are only visible during the night but are also present during the daytime. Recently there has been some evidence discovered that leads us to think auroras only take place at night.

Researchers from Johns Hopkins University say that the aurora is three times more likely to form in darkness than in Sunlight. An aurora forms when charged particles from the Sun encounter Earth's magnetic field. When the particles collide with the upper atmosphere, they create an electric current. When this current is disrupted, the voltage change will discharge energy as heat and the lights of the aurora.

"Who but God can conceive such infinite scenes of glory? Who but God could execute them, painting the heavens in such gorgeous displays?" - Author Unknown

The scientists looked at satellite readings of those charged particles and found that the auroras form more often in darkness when the particles in the atmosphere don't conduct electricity as well. At night, the electrical currents are more likely to be disrupted and discharge their energy in bands, in the form of aurora.

We usually think of space and the sky as a quiet place. However some people think the aurora make sounds. Some scientists have even gone so far as to record some sounds believed to be auroras. Here is a recording of some Auroral Sounds.

Occurences of aurora have been recorded for some time by people other than scientists. The Roman Emperor Tiberius went so far as to dispatch his fire-brigades to the port of Ostia because a bright red aurora convinced him that a vast fire had broken out. Gervase of Canterbury saw red aurora on November 29th, 1177, He said: "There appeared in Kent a certain redness like burning flames flying in the movements of the wind. Indeed, some affirmed very plainly that fiery dragons with twisted heads were seen that same hour."