Northern Lights

The view from directly beneath the Aurora shows dazzling bands of light with huge depth, and often with colour! Be assured that no experience can match the real light show in the arctic sky.

The POES Auroral Activity website provides current visual imaging of the auroral oval.

The Northern Lights, or the Aurora borealis as some call it, is nature's own gigantic light-show. It is a phenomenon that can be seen in both the northern and southern hemispheres (the Aurora australis, or Southern Lights appear in the southern hemisphere) if conditions are right.

There are three things needed for an Aurora light show:

1. A clear night
2. Gases
3. Solar Wind

A CLEAR NIGHT is weather dependant. Even with out clear skies there can still be Auroral activity, but we won't be able to see it from Earth.

There are all sorts of GASES in the atmosphere. It is the different gases which cause the Aurora to change colour

SOLAR WIND comes from the sun. The sun has a number of holes in its corona (outer layer). High energy particles stream out of these holes and are thrown out into our solar system. When solar wind particles collide with the gases in the atmosphere, the energy is transferred into light. When billions of these collisions happen at the same time, together they produce the Northern Lights.

We can only have Auroral activity in high latitudes (far north or far south) because of the magnetic fields near the poles. Most people are familiar with magnetic north - the strong force that pulls your compass needle but some people don't realize that there is also a magnetic field around the south pole. The solar wind particles needed for an Aurora event are pulled into the earth's atmosphere by these magnetic fields.

This topic has long been a source of debate but it seems they do! Now, many people report hearing a 'swish' as the lights move and flicker in the sky. Others claim to hear a electrical, crackling sound. Being the helpful CNSC research people we are...here are a couple of the theories relating to Auroral sound.

SWISHING - The fact that these sounds seem to accompany movement in the Northern Lights presents a minor difficulty. With the Aurora occuring about 80-300km above ground, there should be a delay between movement and sound. Similar to that of thunder and lightning.In addition, the air is thin up there, too thin to effectively carry sound over great distances. This suggest that Auroral sounds must be created near the observer, possibly even inside their head! No, not imaginary, but a 'leakage of the electrical impulses from the nerves in the eye (carrying images of the aurora to the brain) into the part of the brain the processes sound'. Northern Lights are often viewed in a very quiet, natural environment.

Without sound signals to process, the brain notices these tiny electrical leakages and, as a result, the noise changes along with the Aurora! Try testing this explanation by covering your eyes when this sound occurs.

CRACKLING - Ligtning storms, aurora and the Earth's magnetosphere all produce electromagnetic signal in the extremely-low-frequency to very-low-frequency radio spectrum. Unfortunately for the casual observer, these radio waves cannot be listened to without an audio-frequency ELF-VLF radio receiver.

Radio emissions are being studied both via ground-based receiving systems as well as orbiting spacecraft receivers. To listen to these unique sounds and find out more about radio wave research, check out Stephen P. McGreevey's ELF-VLF recordings and the auroral chorus homepage.

Sunspot activity occurs in an 11 year cycle and this, in turn causes variation in the northern lights as a result of changes in solar wind. Generally, during the summer (May, June, July) when nighttime skies remain relatively bright, the aurora is not readily visible. Early fall (August, September) and late winter/early spring (late January through April) present better viewing opportunities.

The following link represents the 'Clear Sky Clock' for the Churchill area. It provides the current two-day forecast for sky watchers. Blue blocks are clear sky, white ones represent cloud cover.

Click on the image below for detailed information...

Global aurora predictions can be found through the University of Alaska - Fairbanks Geophysical Institute website. These predictions are 'based on interpretations of satellite observations of active structures on the sun and of the solar wind between the sun and the earth'.

Find out what the Auroral Oval is up to right now! OVATION is a real-time online model defining the position and intensity of auroral activity. This project is available thanks to data from the DMSP satellites, from NASA's Polar UVI imager, and from the University of Alaska, Fairbanks Meridian Scanning Photometer.

Learn how to predit the Aurora with the Canadian Space Agency's Tips on Viewing Aurora site. Be sure to check out their space weather forecast as well.

Research into space physics and the aurora borealis is currently being conducted by the Auroral Particles and Imagery Group at The Johns Hopkins University Applied Physics Laboratory (JHU/APL). Check out some of the findings and questions raised by their Magnetospheric and Ionospheric Physics Research Projects (aurora stuff...).

David P. Stern and Mauricio Peredo have an created an excellent online resource exploring the Earth's magnetoshpere and related phenomena. Start with their Close Up of the Aurora page and explore from there!

Here is an excellent educational resource for teachers and students. P.O.E.T.R.Y. provides the latest information about auroral science, and the study of Earth's magnetic field. **EDUCATORS** Find more innovative programs, such as P.O.E.T.R.Y., on the CNSC Education Page!

To learn more about aurora and astronomy, call 204-675-2307 for information about our Winter Skies Learning Vacation non-credit course.