Peruvian astronomers said Thursday that evidence shows a meteorite crashed near Lake Titicaca over the weekend, leaving an elliptical crater and magnetic rock fragments in an impact powerful enough to register on seismic charts.
As other astronomers learned more details, they too said it appears likely that a legitimate meteorite hit Earth on Saturday — an rare occurence.
The Earth is constantly bombarded with objects from outer space, but most burn up in the atmosphere and never reach the planet's surface.
Only one in a thousand rocks that that people claim are meteorites turn out to be real, according to Jay Melosh, an expert on impact craters and professor of planetary science at the University of Arizona.
Melosh was skeptical at first, initially calling it a "non-meteorite" and suggesting that the crater might have possibly come from below as a volcanic eruption.
Then scientists learned of more details about the crater, as well as witness descriptions of a thunderous roar and a rain of smaller rocks coming down.
"It begins to sound more likely to me that this object could indeed be a meteorite," Melosh said Thursday.
Such impacts are rare, and astronomists still want to do other tests to confirm the strike.
Other details don't add up, they said — such as witness accounts of water in the muddy crater boiling for 10 minutes from the heat.
Meteorites are actually cold when they hit Earth, astronomists say, since their outer layers burn up and fall away before impact.
Experts also puzzled over claims that 200 local residents were sickened by fumes from the crater. Doctors who examined them found no evidence of illness related to the meteorite, and one suggested a psychosomatic reaction to the sight and sound of the plunging meteor.
More details emerged when astrophysicist Jose Ishitsuka of Peru's Geophysics Institute reached the site about 6 miles from Lake Titicaca.
He confirmed that a meteorite caused a crater 42 feet wide and 15 feet deep, the institute's president, Ronald Woodman, told The Associated Press on Thursday.
Ishitsuka recovered a 3-inch magnetic fragment and said it contained iron, a mineral found in all rocks from space. The impact also registered a magnitude-1.5 tremor on the institute's seismic equipment — that's as much as an explosion of 4.9 tons of dynamite, Woodman said.
Local residents described a fiery ball falling from the sky and smashing into the desolate Andean plain.
Doctors told an Associated Press Television News cameraman at the site that they had found no sign of radioactive contamination among families living nearby. But they said they had taken samples of blood, urine and hair to analyze.
Peasants living near the crater said they had smelled a sulfurous odor for at least an hour after the meteorite struck and that it had provoked upset stomachs and headaches. But Ishitsuka said he doubts reports of a sulfurous smell.
Meteor expert Ursula Marvin said that if people were sickened, "it wouldn't be the meteorite itself, but the dust it raises."
A meteorite "wouldn't get much gas out of the earth," said Marvin, who has studied the objects since 1961 at the Smithsonian Astrophysical Observatory in Massachusetts. "It's a very superficial thing."
Peter Schultz, a meteor crater specialist at Brown University who is eager to visit the Peruvian site, said the latest details suggest this might be an unusual type of meteor strike, and that given the crater's size, the original meteoroid had to have been at least 10 feet in diameter before breaking up.
"With everything I see reported now, it seems to me like we just got hit," Schultz said.
Justina Limache, 74, told the Lima daily El Comercio that when she heard the thunderous roar from the sky, she abandoned her flock of alpacas and ran home with her 8-year-old granddaughter.
She said that after the meteorite struck, small rocks rained down on the roof of her house for several minutes and she feared the house was going to collapse.
Modesto Montoya, a member of the medical team, told El Comercio that fear may have provoked psychosomatic ailments.
"When a meteorite falls, it produces horrid sounds when it makes contact with the atmosphere," he said. "It is as if a giant rock is being sanded. Those sounds could have frightened them."