Aurora Borealis

Northern Lights Questions

 
 
 
 

When?

Aurora Season is from the end of August until the first week of April.
Auroras dance all year, but night is too light from Mid April to Mid August.

What time?

Auroras frequently appear after dinner, from 9~24.
Auroras are unpredictable and may come earlier or later.

Where?

Just step outside the hotel as you can see in the photo above.
They often rise from the north, expand overhead, moving east to west.

Why?

Solar winds collide with earth’s magnetosphere, creating light.
Aurora science has just begun: learn more on wikipedia’s page.

Forecasts?

The best short term forecast is here @ The Icelandic Meteorological Office.
It’s the only aurora forecast site that shows local cloud coverage.

For technical aurora forecasts, try this page.

Long Term Forecasts?

Good news!
2019~20 should be good! And increasingly better for the next 4-5 years.

The solar magnetic activity cycle is about 11 years — we have passed its minimum.

The sun rotates every 27 earth days.

Sort of: circa 24 days at the equator, 38 days at the poles, because its fluid and variable.

For viewing, this means that If auroras are good today, then chances are also good in about a 27 days.

Photos?

Cameras and smart phones keep getting better: use whatever you have in hand.

Brace yourself to steady your camera, or use a tripod.
Forgot yours? Please ask reception for a guest’s tripod.

BE READY.

Want to know more? Ask our photographer.

Apps?

Yes, there are aurora and forecast and specific photo apps. We try them all…

For forecasts, the free links above are most suitable. Apps repackaging the same data.

More for Geeks

NOAA SPACE WEATHER PREDICTION CENTER'S EXPLANATION OF AURORA BOREALIS PHYSICS

"The Aurora Borealis (Northern Lights) and Aurora Australis (Southern Lights) are the result of electrons colliding with the upper reaches of Earth’s atmosphere. (Protons cause faint and diffuse aurora, usually not easily visible to the human eye.)

The electrons are energized through acceleration processes in the downwind tail (night side) of the magnetosphere and at lower altitudes along auroral field lines.

The accelerated electrons follow the magnetic field of Earth down to the Polar Regions where they collide with oxygen and nitrogen atoms and molecules in Earth’s upper atmosphere.

In these collisions, the electrons transfer their energy to the atmosphere thus exciting the atoms and molecules to higher energy states. When they relax back down to lower energy states, they release their energy in the form of light. This is similar to how a neon light works."

DISTANCE ABOVE

The aurora typically forms 80 to 500 km above Earth’s surface. 

WHERE

Earth’s magnetic field guides the electrons such that the aurora forms two ovals approximately centered at the magnetic poles. During major geomagnetic storms these ovals expand away from the poles such that aurora can be seen ... [halfway to the equator, and on rare occasions, as fas south as Hawaii.] 

SHAPES

Aurora comes in several different shapes. 

Often the auroral forms are made of many tall rays that look much like a curtain made of folds of cloth.

During the evening, these rays can form arcs that stretch from horizon to horizon. 

Late in the evening, near midnight, the arcs often begin to twist and sway, just as if a wind were blowing on the curtains of light. 

At some point, the arcs may expand to fill the whole sky, moving rapidly and becoming very bright. 

This is the peak of what is called an auroral substorm. 

Then in the early morning the auroral forms can take on a more cloud-like appearance.

These diffuse patches often blink on and off repeatedly for hours, then they disappear as the sun rises in the east. 

BEST OBSERVED WHERE

The best place to observe the aurora is under an oval shaped region between the north and south latitudes of about 60 and 75 degrees. 

At these polar latitudes, the aurora can be observed more than half of the nights of a given year. 

When space weather activity increases and more frequent and larger storms and substorms occur, the aurora extends equatorward. 

During large events, the aurora can be observed as far south as the US, Europe, and Asia. During very large events, the aurora can be observed even farther from the poles.

Of course, to observe the aurora, the skies must be clear and free of clouds. It must also be dark so during the summer months at auroral latitudes, the midnight sun prevents auroral observations.

SPEEED & ENERGY

Solar winds carrying charged plasma particles-free electrons and protons traveling between 400-1,000 km/sec (1,4M ~3,6M Kmh, 900K ~2,2M mph) and has been recorded at 10,000 km/sec. 

It take about one day to reach earth, collides with the magnetosphere, and upon a magnetic reconnection of the solar wind's passing tails, the energy snaps back and charges gas atoms and molecules in the upper atmosphere concentrated in the geomagnetic fields. 

The energy is released by quantum leaps which generate light: oxygen produces mostly green light, and nitrogen red light. Other solar wind streams are milder and slower, taking 7-10 days to reach the earth.

The Aurora Borealis generates up to an estimated one million megawatts of magnetic energy. [How did they calculate that?]

IS THE AUROA OVAL AND THE ARCTIC CIRCLE THE SAME?

No. The Aurora is not parallel or directly related to the Arctic Circle, but their paths do cross. The aurora annulus is off center, and space weather phenomena, while the Arctic Circle is a terrestrial concept (see more in Questions).