‘Heat lightning’ sparks curiosity in Thiruvananthapuram

On Sunday, night sky was lit up with strange, colourful lights in the eastern skies

The night sky over Thiruvananthapuram on Sunday sparked discussions as residents reported witnessing strange, colourful lights in the eastern skies.

The phenomenon, commonly referred to as heat lightning, has captivated residents and prompted numerous inquiries at the Astronomical Observatory of the University of Kerala.

R. Jayakrishnan, Honorary Director of the observatory, addressed the surge of questions, clarifying the science behind the intriguing lights. “What people observed is heat lightning, a term used to describe the light from a distant thunderstorm that is too far away for the accompanying thunder to be heard or the flash to be seen,” he said.

The Associate Professor at the university’s Physics department elaborated on the physics involved, noting that sound travelled differently through varying temperatures and densities in the atmosphere. “The sound of thunder can typically only be heard up to about 10 miles from the source,” he said.

Factors such as mountains, trees, or even the earth’s curvature can obscure the view of the storm, allowing only the light to be visible.

While many often misconstrue heat lightning as a distinct type of lightning, Dr. Jayakrishnan clarified that it was simply light from far-off thunderstorms reflecting off higher clouds. The sound of thunder often reflected off earth’s surface and the resultant rumbling sound was partly due to these reflections. This reflection and refraction could leave voids where thunder could not be heard. Usually, the troposphere would reflect the light, and leave out the sound. The phenomenon resulted in faint flashes that could be seen while the thunder remained inaudible due to atmospheric conditions, the scientist said.

Published - September 30, 2024 08:33 pm IST