September 21, 2007
An object that struck the high plains of Peru on Saturday, causing a mysterious illness among local residents, was a rare kind of meteorite, scientists announced today.
A photo shows a crater that formed in the southern Peruvian town of Carangas, near the border with Bolivia, on September 16, 2007.
Scientists have now confirmed that the cause was a meteorite crash and that the mysterious illnesses that followed the impact were the result of arsenic fumes released by the blast.
Photograph by Miguel Carrasco/La Razon/Reuters
(See related news photo: "Mysterious Space Object Crashes Into House" [January 5, 2007].)
 Photo in the News: Mysterious Space Object Crashes Into House January 5, 2007—It looks like a shiny lump of fool's gold, and it certainly has authorities fooled as to just what it is. This metallic rocklike object crashed through the roof of a New Jersey home on January 2, ripping through the ceiling and ricocheting off a tiled bathroom floor before lodging in a wall. No one was hurt by the impact, but local detectives trying to identify the mysterious debris may have their professional egos a little bruised. "I've never seen anything like it in my career," Lt. Robert Brightman of the Freehold Township Police Department told the Associated Press at a press conference yesterday. Experts from the U.S. Federal Aviation Administration have already inspected the 13-ounce (0.4 kilogram) lump and determined that it is not a stray airplane part. Another test found that the object is not radioactive, although it does appear to be magnetic. Some astronomers have speculated that that the object could be a meteorite, since the Quadrantid meteor shower occurs annually in early January. But meteor showers typically involve small particles of icy rock, not big metal chunks, so if the mass is a meteorite, it's likely an unusual one. Other theories have suggested that the lump is a tool lost by an astronaut or flotsam from an orbiting satellite that melted as it entered Earth's atmosphere. Brightman said scientists are currently testing the object and hope to have results by the end of the week. |
A team of Peruvian researchers confirmed the origins of the object, which crashed near Lake Titicaca, after taking samples to a lab in the capital city of Lima (see Peru map).
Nearby residents who visited the impact crater complained of headaches and nausea, spurring speculation that the explosion was a subterranean geyser eruption or a release of noxious gas from decayed matter underground.
But the illness was the result of inhaling arsenic fumes, according to Luisa Macedo, a researcher for Peru's Mining, Metallurgy, and Geology Institute (INGEMMET), who visited the crash site.
The meteorite created the gases when the object's hot surface met an underground water supply tainted with arsenic, the scientists said.
Numerous arsenic deposits have been found in the subsoils of southern Peru, explained Modesto Montoya, a nuclear physicist who collaborated with the team. The naturally formed deposits contaminate local drinking water.
"If the meteorite arrives incandescent and at a high temperature because of friction in the atmosphere, hitting water can create a column of steam," added José Ishitsuka, an astronomer at the Peruvian Geophysics Institute, who analyzed the object.
By Wednesday, according to Macedo, all 30 residents who felt ill reported feeling better.
"People Were Extremely Scared"
Locals described the meteorite as a bright, fiery ball with a smoke trail. The sound and smell rattled residents to the point that they feared for their lives, Ishitsuka said.
The meteorite's impact sent debris flying up to 820 feet (250 meters) away, with some material landing on the roof of the nearest home 390 feet (120 meters) from the crater, Ishitsuka reported.
"Imagine the magnitude of the impact," he said. "People were extremely scared. It was a psychological thing."
The meteorite's crash also caused minor tremors, shaking locals physically and emotionally.
"They were in the epicenter of a small earthquake," Montoya, the nuclear physicist, said.
The resulting crater resembles a muddy pond measuring 42 feet (13 meters) wide and 10 feet (3 meters) deep.
Solving the Mystery
Even as meteorite samples arrived in Lima Thursday for testing, Peruvian scientists seemed to unanimously agree that it was a meteorite that had struck their territory.
"Based on the first-hand reports, the impact and the samples, this is a meteorite," Macedo, of INGEMMET, said.
Tests revealed no unusual radiation at the site, though its absence didn't rule out a meteorite crash.
"Everything has radioactivity, even underground rocks," Montoya said. "But nothing out of the ordinary was found."
Preliminary analysis by Macedo's institute revealed no metal fragments, indicating a rare rock meteorite. Metal stands up better to the heat created as objects enter Earth's atmosphere, which is why most meteorites are metallic.
The samples she reviewed had smooth, eroded edges, Macedo added.
"As the rock enters the atmosphere, it gets smoothed out," she said.
The samples also had a significant amount of magnetic material "characteristic of meteorites," she said.
"The samples stick to the magnet," Ishitsuka, the astronomer, confirmed. "That shows that there is iron present."
Water samples at the crater proved normal, but the color and composition of soil were "unusual" for the area, Macedo noted.
José Machare, a geoscience adviser at INGEMMET, said x-ray tests conducted on the samples earlier today further confirmed the object's celestial origins.
He said the group's findings put to rest earlier theories that the object was a piece of space junk or that the crater had formed by an underground explosion.
"It's a rocky fragment," Machare said, "and rocks that fall from the sky can only be meteorites."
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