Glittering Northern Lights More than Just Light Shows

The spectacular and dazzling lights form the northern lights of the Earth are more than just what they appear to us. They can be termed as a musical light show. The ones to reveal this new exploration for the first time is the Finnish researchers. According to Aalto University in Finland, aurora borealis produce sound is true.   

The occurrence of sound that accompanies Northern Lights have been prevailing for quite some time in folktales, but could not support this due to lack of scientific approach. But the new results from the 12 yearlong study has finally revealed that Northern lights are accompanied with a mysterious clapping sound that originate from only 230 feet above ground. They team was able to track this using three microphones to record the sounds which they later triangulated a position for the source of the noises.

Professor Unto K. Laine from Aalto University said, "Our research proved that, during the occurrence of the northern lights, people can hear natural auroral sounds related to what they see.  In the past, researchers thought that the aurora borealis was too far away for people to hear the sounds it made. This is true. However, our research proves that the source of the sounds that are associated with the aurora borealis we see is likely caused by the same energetic particles from the sun that creates the northern lights far away in the sky."

The auroras, both surrounding the north magnetic pole (aurora borealis) and south magnetic pole (aurora australis) occur when highly charged electrons from the solar wind interact with elements in the earth's atmosphere. Earth's magnetic field lines direct these particles over the planet's poles, causing the northern lights in the Northern Hemisphere and the southern lights, or aurora australis, in the south. These are more recurrent and brighter during the intense phase of the solar cycle when coronal mass ejections increase the intensity of the solar wind

Even after tracking the occurrence of the sound that appears with the Northern lights, the researchers are unable to detect what exactly causes these auroral sounds. Because of this sonic diversity, several different mechanisms might be at work.

In contrast to the very clear clap of the recording, the Aalto University article says, "These sounds are so soft that one has to listen very carefully to hear them from the ambient noise." 

The new study will be published in the proceedings of the 19th International Congress on Sound and Vibration, a conference that's meeting in Vilnius, Lithuania from July 8 through July 12.