Weekend Meteor Shower

Earth is about to pass through a stream of debris from Halley's comet, source of the annual Orionid meteor shower.  Forecasters expect more than 15 meteors per hour to fly across the sky on Saturday morning, Oct. 22nd, when the shower peaks.

"Although this isn't the biggest meteor shower of the year, it's definitely worth waking up for," says Bill Cooke of the NASA Meteoroid Environment Office. "The setting is dynamite."

Cometary debris streams like Halley's are so wide, the whole Earth-Moon system fits inside. So when there is a meteor shower on Earth, there's usually one on the Moon, too.  Unlike Earth, however, the Moon has no atmosphere to intercept meteoroids.  Pieces of debris fall all the way to the surface and explode where they hit.  Flashes of light caused by thermal heating of lunar rocks and moondust are so bright, they can sometimes be seen through backyard-class telescopes.

http://science.nasa.gov/science-news/science-at-nasa/2011/20oct_orionids/

Rare 4.6-magnitude earthquake near San Antonio

SAN ANTONIO, TX -- A rare and record-breaking South Texas earthquake with a preliminary magnitude of 4.6 struck near rural Karnes County on Thursday morning, rattling homes and causing faint tremors in downtown San Antonio.

No injuries or major damage was reported, and the light quake wasn't even noticed by some residents living close to the epicenter, near Karnes City. Yet small vibrations felt in San Antonio did cause occupants to briefly evacuate a downtown federal building as a precaution.

http://abclocal.go.com/ktrk/story?section=news/state&id=8398974