Gilmer Free Press
Stargazing - 07.19.12
The pale glow of the Milky Way arches high overhead on summer evenings.
The Milky Way is the combined light of millions of stars in the flat disk of our galaxy.
The center of the galaxy lies in Sagittarius, at the southern end of the Milky Way.
Back in late April, a meteor startled residents of California and Nevada when it exploded, showering the mountains with bits of rocky debris. But that’s not the first time that space rock has rained on the West. Another cosmic blast took place 100 years ago today.
Around dinnertime on July 19th, 1912, several explosions rattled the desert town of Holbrook, Arizona. Minutes later, rocks fell from the sky — about 14,000 of them. They were the remains of a cosmic boulder that blew up as it slammed into the atmosphere.
Thousands of bits of rock and metal pelt our planet every day. Most are no bigger than grains of sand, so they vaporize before they hit the ground. But a few of the bigger ones make it to the surface — either whole or in pieces.
That’s what happened at Holbrook. The intense pressure generated by the boulder’s flight through the atmosphere caused it to shatter into thousands of pieces. When they hit the ground, such pieces are known as meteorites.
The largest Holbrook meteorite weighs about 15 pounds. The smallest are tiny pebbles. In fact, a couple of decades after the incident, a scientist who visited the site found hundreds of these pebbles in anthills built by red ants.
Coincidentally, Holbrook is only a few miles east of the site of yet another impact. A giant meteorite slammed into the landscape about 50,000 years ago, creating the most famous cosmic “scar” on Earth’s surface — the Arizona Meteor Crater.