Lightning, as we know, is an awesome burst of energy. When lightning strikes, some of that energy can be converted into radio waves that then zip through space along Earth's magnetic field, so that lightning in Alaska can be heard as "whistlers" on a radio receiver all the way in New Zealand.
These whistlers from lightning sound startlingly like the sound effects of a modern video game when converted to audible frequencies. A century ago, soldiers thought they sounded like grenades whistling through the air.
At LiveScience, Becky Oskin reports on a new study that solves the mystery of a sudden burst of whistlers at a listening station in Dunedin, New Zealand. The answer came from Alaska, where an erupting volcano had sparked lightning:
On July 12, 2008, Collier and his colleagues detected an astounding peak in Dunedin's whistler activity, which initially defied explanation. The network picked up more than 15,000 whistlers that day, and the researchers found even more when they pored over the records.
Seeking a source for the spike in whistlers, Collier sent Antel searching through records of lightning strikes and volcanic eruptions. She found a match in the Aleutian Islands.
Alaska's Mount Okmok erupted on July 12, 2008. Within 35 minutes, the whistler count at Dunedin started rising, Antel and her co-authors reported. The network recorded more than 21,000 whistlers within 10 hours of the eruption. After Okmok's ash plume collapsed, cutting off the lightning, the whistlers quieted.
Read more about the weird phenomenon of whistlers at LiveScience.
Top image: AP Photo/Julio Cortez