New study might change understanding of size and speed of Earth-bound meteorites

March 12th, 2008 - 1:47 pm ICT by admin  

Washington, March 12 (ANI): The study of a Peruvian meteorite has yielded an interesting conclusion as to how it made it to Earth, which could upend the conventional wisdom about the size and type of meteorites that can strike Earth.

Professor Peter Schultz of the Brown University made the study.

The meteorite, which was studied upon, slammed into a dry riverbed near Carancas in Peru, leaving a 49-foot-wide crater. Soil ejected from the point of impact was found nearly four football fields away.

When Schultzs team analyzed the soil where the fireball hit, he found planar deformation features, or fractured lines in sand grains found in the ground.

Along with evidence of debris strewn over a wide area, the shattered sand grains told Schultz that the meteorite had maintained a high rate of speed as it shot through the atmosphere. Scientists think it was traveling at roughly 15,000 miles per hour at the moment of impact.

According to Schultz, Normally with a small object like this, the atmosphere slows it down, and it becomes the equivalent of a bowling ball dropping into the ground.

It would make a hole in the ground, like a pit, but not a crater. But this meteorite kept on going at a speed about 40 to 50 times faster than it should have been going, he added.

Scientists have determined the Carancas fireball to be a stony meteorite a fragile type long thought to be ripped into pieces as it enters the Earths atmosphere and then leaves little more than a whisper of its journey.

But yet, the stony meteorite that struck Peru survived its passage mostly intact before impact.

This just isnt what we expected, said Schultz. It was completely inconsistent with our understanding how stony meteorites act, he added.

Schultz believes that fragments from the Carancas meteorite may have stayed within the fast-moving fireball until impact. How that happened, according to Schultz, is due to the meteorites high speed.

At that velocity, the fragments could not escape past the shock-wave barrier accompanying the meteorite and instead reconstituted themselves into another shape, he said.

That new shape may have made the meteorite more aerodynamic meaning it encountered less friction as it sped toward Earth, hitting the surface as one large chunk.

It became very streamlined and so it penetrated the Earths atmosphere more efficiently, said Schultz.

Schultzs theory could upend the conventional wisdom that all small, stony meteorites disintegrate before striking Earth. If correct, it could change the thinking about the size and type of extraterrestrial objects that have bombarded the Earth for eons and could strike our planet next. (ANI)

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