Above: Logo of the AuroraMAX project (Canadian Space Agency)
Fast Fact: Auroras are called “northern lights,” or “aurora borealis,” when they occur in northern latitudes and “southern lights,” or “aurora australis,” when they occur in southern latitudes.Auroras are dazzling displays of brightly coloured lights in a dark sky that occur primarily in high latitudes (closer to the Arctic and the Antarctic). Those of us living at lower latitudes (father from the Arctic and the Antarctic) can still watch live feeds of auroras occurring in Yellowknife, Northwest territories, thanks to the AuroraMAX project.
In order to explain the origins of an aurora, we must begin with the sun. Much like the Earth, the sun has its own magnetic field, gravitational field, and atmosphere. Because the sun’s atmosphere is so hot, particles within it become very “excited” and move extremely fast. When this so-called “kinetic energy” reaches a certain level, these highly charged particles (primarily protons and electrons) overcome the gravitational pull of the sun. As a result, they speed away from the sun and toward the Earth in a phenomenon known as "solar winds."
As the particles approach our planet, the Earth’s magnetic field directs them toward the upper part of the atmosphere, called the thermosphere, where they collide with and excite gas particles. Consequently, these gas particles reach higher energy levels, which throws them off balance. To return to their initial energy levels, they release light particles called photons. When enough photons are released at the same time, a visible aurora is produced.
Fast Fact: Auroras occur predominantly near the North and South Poles because that is where the earth’s magnetic field is strongest. A five-year outreach project, called AuroraMAX, was launched in 2008 to record and publicly broadcast auroras occurring in Yellowknife. The project is designed to show the evolution of auroras until 2013, when the sun will reach the most active period of its current eleven-year cycle. As this so-called “solar maximum” approaches, more and more particles in the sun's atmosphere will gain high enough energies to escape its gravitational pull. Solar winds will increase and auroras will become more intense.
To learn more about the AuroraMAX project and to see live broadcasts, visit http://www.asc-csa.gc.ca/eng/astronomy/auroramax/connect.asp.
Aurora... fabled glowing lights of the Sun-Earth connection (NASA)
http://pwg.gsfc.nasa.gov/polar/EPO/auroral_poster/aurora_all.pdf AuroraMAX Live (Canadian Space Agency)
http://www.asc-csa.gc.ca/eng/astronomy/auroramax/connect.asp The Sun is heading towards its Solar Maximum (three-minute video explaining solar winds, the solar maximum, the earth’s magnetic field, and auroras)