Dazzling pink auroras captured over Norwegian skies: Check it out
On the night of December 10, a pink aurora was seen over the skies of Tromso in Norway. This stunning aerial display was triggered by a magnetic substorm. As opposed to the commonly-observed green auroras, pink auroras form when energetic particles from space descend lower than usual and strike nitrogen molecules at an altitude of 100 km or lesser.
Why does this story matter?
- Of late, solar flares and geomagnetic storms appear to have become more frequent as the Sun is at the peak of its solar cycle.
- Up until 2005, NASA's Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) satellite, was used to study auroras.
- Recently, the space agency launched ACES 2 (Aurora Current and Electrodynamics Structures 2), a rocket-based mission, to study the electrical circuitry behind the auroras.
Check out the pink aurora that appeared on December 10
First, what is a magnetic substorm?
Starting with the most basic difference- magnetic storms occur across the globe, while magnetic substorms are confined to the auroral zones. Also called auroral substorms, they are brief, lasting barely 2-3 hours, but they occur more frequently. They are considered to be a part of the normal interaction that occurs when solar winds from the Sun come in contact with the Earth's magnetosphere.
The color of auroras is also determined by the altitude
The colors of auroras depend on the altitude and type of atoms involved. When charged particles strike oxygen at lower altitudes, the most-familiar green auroras are seen but it produces a reddish glow when it occurs at higher altitudes. Blue and purple auroras are caused due to hydrogen and helium atoms, respectively, but our eyes cannot see in this range of the electromagnetic spectrum.
Sometimes active auroras interfere with communication systems
Auroras are caused when solar winds, a stream of electrically charged particles originating from the Sun, interact with the Earth's magnetic field. Mostly, they occur 97-1,000km above the surface of the Earth. They are usually harmless but sometimes, active auroras and magnetic storms can disrupt radar and radio signals. The intense magnetic storms can even disable communication satellites.