When giant space rocks rip the Earth

MFNC March 5 meeting features Meteorite impacts through geological time

Some 66 million years ago, dinosaurs like T. Rex and Triceratops populated the lush tropical forests that blanketed what is now Western Canada. Until, that is, a catastrophic event obliterated them and half of Earth’s species.

Dr. John Percival, senior research scientist at the Geological Survey of Canada (GSC), unpacks what happened:

“A 10- to 15-km diameter meteorite travelling at 10 km/second struck the Yucatan Peninsula in present day Mexico, vaporizing rocks within a 150-km wide, 20-km deep crater. Rock vapour enveloped the globe, resulting in the extinction of about half of Earth’s species, including the dinosaurs. This crater, called the Chicxulub Crater, is now covered with sediments and seawater.”

Percival reassures us:  “While there is an almost continuous rain of interplanetary dust, regular meteorite showers and occasional fireballs entering the atmosphere, only rarely do objects large enough to excavate craters strike the Earth.”

Learn more at the March 5 MFNC meeting, when he will present Meteorite Impacts through Geological Time, an illustrated tour of such impact events, including notable Canadian craters like the closest one, the 450-million-year-old Brent crater in eastern Algonquin Park; the most obvious one, known for its perfect circular crate, the 1.4-million-year-old Pingualuit crater within the Ungava peninsula in far-north Quebec; and the richest one, the 1.85-billion-year-old Sudbury structure.

If the Brent Crater impact happened today, writes Charles O’Dale on crater.ca, “every tree in Algonquin Park would be flattened and covered with ejecta, Ottawa would experience a major earthquake and the most of the windows in the city’s buildings would be blown out!”

Pingualuit Crater Lake – credit NASA Earth Observatory

Some unearthed nuggets:

  1. The vast majority of meteorites are pieces of asteroids, the small rocky bodies that orbit the Sun mostly between Mars and Jupiter.  American Museum of Natural History
  2. Small meteors regularly impact the moon and Earth. On Earth, they usually burn up in the atmosphere, or land in uninhabited areas where they go undetected. But, on the moon, they constantly form craters and impact basins.  New Scientist
  3. Observers who closely watched the recent Super Blood Wolf Moon eclipse spotted an extra bonus: a meteoroid flying into the surface of the moon, mid-eclipse. Check out this video clip. [at  http://digg.com/2019/super-blood-wolf-moon-meteor-strike ]
  4. A Mars-sized meteor is thought to be responsible for striking the primitive Earth, ejecting material that became the Moon about 4.53 billion years ago. John Percival
  5. Researchers rarely observe an asteroid both in space and again while plummeting to Earth as a meteor. The history-making recovery of the 2018 LA meteorite in a Botswana Game Reserve in June 2018 was only the second time that a meteorite has been recovered from an asteroid first spotted in space. As 2018 LA burst into pieces, it created infrasound waves equivalent to the explosion of 300-500 tons of TNT. Astronomy Magazine
  6. The first meteorite impact crater ever discovered under Earth’s ice sheets was found November 2018 in Greenland. At the time of writing, a possible second 22-mile crater had just been found under a mile of ice 114 miles away.  @NASA Twitter.

Don’t miss: Meteorite impacts through geological time

When: Tuesday, March 5, 7:30 p.m.

Where: Arnprior Curling Club, 15 Galvin Street, Arnprior

Cost: Meetings (and presentations) are free for Club members and $5 for guests.

Guests are welcome at this and every meeting of the Macnamara Club.