Finding a meteorite's final resting place

Nov 27, 2008
Chris Herd has developed a new technique to locate undiscovered meteorite craters.

(PhysOrg.com) -- University of Alberta researcher Chris Herd doesn't want people craning their necks, worrying about giant rocks falling from space. But he's unleashed new technology that could prove meteorite impacts with Earth aren't as rare as we think.

Herd, an associate professor of earth and atmospheric science agrees that "yes," a giant meteorite, almost 10 kilometres wide, likely ended the age of the dinosaurs, but will it happen again? "Something that big only happens every tens of millions of years," he said. "It's possible, but only remotely."

If you're counting, the so-called dinosaur-killing meteorite hit Earth 65 million years ago.

And about the Nov. 20 meteorite, estimated to be the size of an office desk, which blazed across the prairie sky and landed somewhere in Saskatchewan? Herd is confident we're safe. "The chances of actually being hit by a meteorite are almost incalculable," he said.

Putting meteorite impacts in perspective was a major concern this week as Herd released details of a new technique to locate undiscovered meteorite craters. The breakthrough came when Herd analyzed a meteorite crater near Whitecourt, 200 kilometres west of Edmonton.

Herd and his colleagues decided they needed an aerial view of the 36 metre-wide crater. "You can't spot it from the air because of the trees," He said, although the solution was close at hand. "We bought Light Detection and Ranging aerial images of the area that already existed."

LiDAR equipment is attached to an aircraft and beams of laser light capture 3-D images of the ground below. The forest industry uses the technology to count trees and determine the topography, but Herd wasn't interested in the trees.

"We asked for the Bare Earth model," he said. "That's terrain with the images of the trees and vegetation stripped away."

It was the breakthrough Herd was hoping for. The image of Whitecourt meteorite crater was clear as day.

Herd sees a bright future for crater counting. "We should be able to look through LiDAR data from wherever it's been acquired and find more undiscovered craters."

Current theories on Earth impacts say meteorites the size and age of the rock that made the crater near Whitecourt happen every 10 years. That's every 10 years for the last 10,000 years. When scientists adjust the numbers to account for meteorite hits in oceans and crater evidence erased by land erosion Herd is still encouraged.

"There should be dozens, maybe a hundred, meteorite craters like Whitecourt."

A meteorite crater can tell a scientist when it came to Earth and what it was made of.

The Whitecourt meteorite fell to Earth about 1,100 years ago. Herd estimates it was about a metre wide. He knows the rock was composed of iron and nickel and that it started its journey through space in the core of a 4.5 billion-year-old asteroid. That asteroid broke apart and pieces of the core became meteorites. So far only half a dozen meteorite craters the age and size of the Whitecourt site have been located.

To find more of them Herd and others are negotiating access for more existing LiDAR surveys. He's already getting tips from people on where to start looking. "People are calling and say they remember seeing a bowl shaped depression in the Earth and we're building a file based on those accounts."

While some people might be looking skyward these days with a little concerned these are great times for Herd.

"I can't get enough of it. Meteorites are all good with me."

Provided by University of Alberta

Explore further: Spinning up a dust devil on Mars

add to favorites email to friend print save as pdf

Related Stories

Fingers pointed as climate talks deadlock

11 hours ago

Accusations flew at deadlocked UN climate talks in Lima on Saturday, as the United States warned that failure to compromise could doom the 22-year-old global forum.

Recommended for you

SDO captures images of two mid-level flares

4 hours ago

The sun emitted a mid-level flare on Dec. 18, 2014, at 4:58 p.m. EST. NASA's Solar Dynamics Observatory, which watches the sun constantly, captured an image of the event. Solar flares are powerful bursts ...

Why is Venus so horrible?

11 hours ago

Venus sucks. Seriously, it's the worst. The global temperature is as hot as an oven, the atmospheric pressure is 90 times Earth, and it rains sulfuric acid. Every part of the surface of Venus would kill you ...

Image: Christmas wrapping the Sentinel-3A antenna

13 hours ago

The moment a team of technicians, gowned like hospital surgeons, wraps the Sentinel-3A radar altimeter in multilayer insulation to protect it from the temperature extremes found in Earth orbit.

Video: Flying over Becquerel

14 hours ago

This latest release from the camera on ESA's Mars Express is a simulated flight over the Becquerel crater, showing large-scale deposits of sedimentary material.

Spinning up a dust devil on Mars

15 hours ago

Spinning up a dust devil in the thin air of Mars requires a stronger updraft than is needed to create a similar vortex on Earth, according to research at The University of Alabama in Huntsville (UAH).

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.