Meet Meteor Crater

METEOR CRATER

A BLAST FROM OUTER SPACE THAT LEVELED TREES AND KILLED EVERY LIVING THING

Not long ago, a tourist pulled off Interstate 40 and drove the five paved miles south to Arizona's Meteor Crater. There he caught the tail end of a lecture by Brad Andes, manager of the privately owned park. Brad stated that the nickel-iron meteor (or a cluster of them) weighing megatons blazed in from the north and struck the Earth's surface, gouging a hole most of a mile in diameter.

In all, about 300 million tons of rock were displaced in a hellish explosion that lasted a mere seven seconds.

Brad paused, allowing the awesome facts to sink in.

The late arrival raised a hand.

"Was anybody hurt?" he asked, and before Brad could respond, the newcomer blurted, "Lucky the damned thing missed the freeway!"

The visitor had not heard the part where Brad dated the cosmic collision at 49,500 years ago, long before people drifted from Asia into the New World, and some 49,480 years before Interstate 40 replaced storybook U.S. Route 66 between Flagstaff and Winslow in northern Arizona. For Brad Andes, the anecdote illuminates two points: the mysteries of stark windswept Meteor Crater stumped nearly everybody until recent times, and there's no telling how humans will react when they learn the truth.

The magnitude and abruptness of the ancient event on the northern Arizona plateau challenge the liveliest imagination. Consider, for example: It was zipping along at 43,000 mph. At that speed, the meteor could have raced from Los Angeles to New York in four minutes.

Despite such gee-whiz superlatives, the Crater apparently escaped notice until 1871. Travelers assumed the unimpressive hump out in nowhere was solid enough to deserve the descriptive name Coon Butte. Then some white folks climbed up and peered into the 600-foot-deep pit. Early scientific explorers wrote the landform off as the primordial work of a steam or gas blowout from below.

But in 1902, the Crater was first visited by a remarkably insightful and stubborn Philadelphia mining engineer: D. Moreau Barringer. Noting the abundance of largeto-tiny metallic meteorites littering the surrounding plain, Barringer concluded that the colossal dimple was an instant's creation of an extraterrestrial body, perhaps a dense, lumpy escapee from one of the solar system's asteroid belts. So certain was Barringer (in the face of criticism bordering on ridicule from other scientists), he gained ownership through a mining claim autographed by President Teddy Roosevelt. For a quarter-century, Barringer prospected and drilled in hope of locating a rich ore body. He spent $600,000 searching for a treasure he figured was worth $1 billion.

Because the Crater is nearly round, Barringer at first assumed the meteor fell straight down, to lodge near the center of the hole. Later, by firing a rifle into thick mud, he determined that bullets made round holes even when entering from a flat angle. Accordingly, other evidence took on fresh meaning. Horizontal rock formations of the south wall were bent upward a hundred feet higher than other levels of the rim. Barringer moved his drill to the southeast. At a depth of 1,000 feet, the bit hit meteorite fragments. At 1,376 feet, the drill froze, as if jammed between objects harder than itself. His money exhausted, Barringer was forced to abandon his quest in 1929.

That year he died, but not without the satisfaction of having his idea accepted by most of his colleagues. He was recognized as the first person to demonstrate that large objects fall out of the solar system onto the surface of the Earth. Appropriately enough, in scientific literature Barringer's name identifies the Crater.

Following his pioneering efforts, science vastly expanded humankind's understanding of Meteor Crater, meteors in general, and the meteorites and depressions they leave behind. Subsequent drilling for the Arizona main mass failed as before, but advanced instruments employing sound waves and electronic sensors determined that much of what remains of the meteor, about 10 percent, indeed lies beneath the south rim. Today geologists believe that about five percent of the original meteor eroded in atmospheric friction, five percent scattered on impact, and 80 percent vaporized. make a hole 60 stories deep, it has to be traveling incredibly fast.

At Meteor Crater were identified two hitherto unknown minerals in Nature: coesite and stishovite. These forms of silica (common sand) can be made in the laboratory, but the process requires extremely high pressure: up to 300,000 pounds per square inch. This implies meteor impact pressures 20,000 times greater than the Earth's atmospheric pressure at sea level.

Refined analyses in recent times have pushed back the presumed age of Meteor Crater. Radiocarbon measurements in the early 1960s produced a date of 25,000 years before the present. But by the mid1980s, scientists studying glow emitted by superheated rock specimens nearly doubled the Crater's age.

Meteor Crater's contributions to other fields of science are manifold. All Apollo astronauts received extensive training at the Arizona site. Guided by what they observed at Meteor Crater, men on the moon more efficiently gathered lunar rock samples.

Using Meteor Crater as a template, and by photographic comparison, it was determined that numerous craters on the Earth, moon, and other planets and their moons were constructed by meteors. Earth's craters, their geometry softened and flattened by erosion and vegetation, are less obvious. But some experts believe that through the ages the surface of Earth was pocked like the face of the moon.

If the scale of Meteor Crater boggles minds, try to envision what it took, 250 million years ago, to blast open the Vrede Fort Ring in South Africa tens of miles in diameter! Or the size of the meteor that whacked Mexico's Yucatan Peninsula 65 million years ago, leading to, in the opinion of distinguished scientists, the extinction of dinosaurs and a massive die-off of 75 percent of Earth's species.

Such speculation periodically ignites meteormania among people prone to worry. Once in a while, Hollywood fuels the phobia with a special-effects extravaganza like 1979's Meteor, in which Sean Connery contends with the unmovable trajectory of an onrushing object while distracted by the irresistible force of Natalie Wood. As part of the motion-picture premiere hype, 70 entertainment journalists were flown by helicopter into Meteor Crater for a firsthand look at the dimensions of doomsday.

Yet lurid printed stories and scary television shows to the contrary, the odds against a meteor event far outweigh the chances of a media event. Two years ago, writing in the scientific journal Nature, University of Arizona and NASA scientists characterized Earth's dense cocoon of gases and vapors as an almost perfectly effective shield against large incoming boulders.

Stated Christopher F. Chyba of NASA, "Put it this way: we don't need a fleet of rockets to blow these things off course. This [collision of an asteroid] does not represent a major threat."

Comforting to Earthlings, in all of written history the formation of only one impact crater on the planet has been recorded. Following a spectacular shower of falling stars February 12, 1947, Russian scientists discovered numerous pits, the largest 60 feet in diameter, a few hundred miles north of Vladivostok. By comparison to Arizona's, the Siberian celestial divot wasn't much.

Also unusual about Meteor Crater is its popularity as a tourist target. Accessible, large-scale, and sharply defined, the Crater is physically attractive. But equally important have been several public-spirited generations of Barringer family owners, who have insisted that the Crater serve as both a monument to the free enterprise spirit of Daniel Moreau, the Senior, and as a research and educational laboratory. In setting up the current operating contract, the agreeing parties recognize "the value to scientific knowledge of the Barringer Meteorite Crater and their joint obligation to allow full access to all parts of the Crater at all reasonable times to all serious students of the sciences."

Says Manager Brad Andes, "I know of no other privately owned and operated natural phenomenon more dedicated to preservation and interpretation." In 1968 the Crater was declared a National Landmark by the Department of the Interior.

As Andes pointed out to his uninformed tourist, the meteor didn't miss the interstate. The interstate missed the Crater. So if you're lucky enough to be traveling along 1-40 in the neighborhood of Meteor Crater, don't you miss it.

WHEN YOU GO

You will join 300,000 other visitors annually when you visit Meteor Crater. The all-weather access road departs Interstate 40, 35 miles east of Flagstaff and 20 miles west of Winslow. From Exit 233, the drive is five miles to the Crater, open to viewing every day of the year. Hours are: May 15 to September 15, 6 A.M. to 6 P.M.; September 16 to May 14, 8 A.M. to 5 P.M. Admission fees are: seniors (60 and older), $6; adults, $7; children six to 12, $1; and ages 13 to 17, $2.

Amenities on the Crater rim include an observation platform, hiking trail, the Museum of Astrogeology offering self-guided tours and guided rim trail hikes, video presentations and hands-on meteorite displays (one weighs 1,406 pounds), gift and lapidary shops, and a cafe. An Apollo space capsule is the centerpiece of the Astronaut Hall of Fame. Astronaut Park memorializes Apollo and Challenger shuttle crews.

Nearby, under management of Meteor Crater Enterprises, is a large RV facility with full hookups, private rest rooms with showers, laundry, minimarket, service station, playground, and recreation room. For more information on Meteor Crater, call (520) 289-2362; for the RV park, (520) 289-4002.