Sunday, May 24, 2009

FULGURITES - PRODUCTS OF LIGHTNING


What does happen when lightning strikes the ground? It transforms the soil it hits into something unique and artistic!! The end result - Fulgurites

Fulgurite is scientific Latin for "lightning stone." Fulgurites are made when lightning strikes the ground. When a bolt strikes the ground, it vaporizes a thin wormhole and melts the zone around it, creating an instant froth of natural hollow glass tubes formed in quartzose sand, or silica, or soil. These fulgurites can be up to several centimeters in diameter, and meters long, but they're quite fragile. Their color varies depending on the composition of the sand they formed in, ranging from black or tan to green or a translucent white. The interior is normally very smooth or lined with fine bubbles; the exterior is generally coated with rough sand particles and is porous. They are rootlike in appearance and often show branching or small holes. This process occurs over a period of around one second, and leaves evidence of the lightning path and its dispersion over the surface.

Finding one is quite rare!

Sunday, May 10, 2009

AURORA BOREALIS


Has anyone ever witnessed these dancing fluorescent ribbons that light up the night sky? Well, I can’t blame you if you haven’t, coz it aint visible from where we Indians live! it is only visible in the sky from the Northern Hemisphere, the chance of visibility increasing with proximity to the North Magnetic Pole, which is currently in the arctic islands of northern Canada.

The northern lights have had a number of names throughout history. The Cree people call this phenomenon the "Dance of the Spirits." The aurora was named after the Roman goddess of dawn, and the Greek name for north wind, Boreas by Pierre Gassendi in 1621. It was long thought to be produced by sunlight reflected from polar snow and ice, or refracted light much like rainbows. But in reality, the phenomenon of aurora is an interaction between the Earth's magnetic field and solar wind. The Earth is constantly immersed in the solar wind, a rarefied flow of hot plasma emitted by the Sun in all directions.

The aurora may last 10-15 minutes, twisting and turning in patterns called "rayed bands", then whirling into a giant green corona in which rays appear to flare in all directions from a central point, and finally fade away.

I’ve been fascinated bout these amazing lights since I was a little kid! I do hope I witness it someday