Scientists Trace Origin of Dinosaur-Killing Asteroid

The age of the dinosaurs lasted more than a hundred million years, which is an unfathomable long time compared with humanity’s mere 300,000 years on this planet. Most species of dinosaurs met their end about 65 million years ago when a large object smacked into the Yucatan peninsula. A team of scientists from the Southwest Research Institute (SwRI) is trying to identify the source of this impact, and the data currently indicates similar asteroids could be more common than we thought.

Even with millions of years of weathering and tectonic drift, the signs of that fateful impact are still visible. The six-mile space rock left a 90-mile crater (known as Chicxulub crater) where it struck the Earth, and it’s still visible with the right equipment. This region of Mexico also has numerous geological abnormalities caused by the impact. Analysis of rock samples in the Chicxulub crater shows that the impactor was similar to the carbonaceous chondrite class of meteorites. These are very old materials, and there are very few chondrites of a similar size today. That raises the question: Where did the dinosaur killer come from?

In the past, teams studying this event have simulated the break-up of larger comets and asteroids in the inner solar system. The idea is these clusters of material could have fallen into Earth’s gravity, with the Chicxulub crater being the largest fragment. None of these explanations completely jive with what we know of asteroids and comets, though. The SwRI team decided to use computer models to track how objects escape from the Great Asteroid Belt between Mars and Jupiter. They were on the search for “escape hatches” where the gravity of planets could nudge asteroids into orbits that cross Earth’s.

The team used NASA’s Pleiades Supercomputer to simulate more than 130,000 asteroids over the course of millions of years. The simulation showed that carbonaceous chondrites from the outer half of the asteroid belt were particularly prone to be ejected in the direction of Earth. Asteroids of similar size to the Chicxulub impactor from this region might break free 10 times more often than previous estimates predicted.

So, that’s troubling, but 65 million years isn’t that long ago in the grand scheme. The SwRI analysis products impacts like this occur every 250 million years, give or take. So, we still have some time, if our luck holds.

Continue reading

New Research Says Dinosaur-Killing Asteroid Struck Earth in Springtime

Scientists have studied the so-called Chicxulub impact for decades but only on millennia timescales. For the first time, researchers have zeroed in on when the asteroid or comet walloped Earth, and they say it happened on an otherwise pleasant spring day.

Dinosaur-Killing Impact May Have Superheated Earth’s Atmosphere for 100,000 Years

The Cretaceous-Paleogene extinction event didn't just kick off a short-term apocalyptic winter — it may have turned the planet's thermostat up dramatically for a hundred thousand years.

Dinosaur-Killing Impact Crater Shows Rock Can Flow Like Fluid

A new study of the Chicxulub crater reveals how fluid rock leaves its mark following an impact.