“When you wish upon a star, your dreams can come true,” said Dr. Bruce Simonson, an Oberlin geology professor. “Unless it’s really a meteorite hurtling to the Earth which will destroy all life. Then you’re pretty much hosed no matter what you wish for. Unless it’s death by a meteor.”

Simonson said that he could not resist opening his lecture “When Asteroids Attack: The Science of Armageddon” with this “demotivational” quote. His lecture took on a much more optimistic tone, though, as he explained the meteoric breakthroughs he took part in adding to the field of geology.

Simonson began by giving the audience an idea of just how much impact a meteorite can have.

The asteroid belt generally orbits Mars and Jupiter and includes such large asteroids as Eros, an ice chunk 33 kilometers in diameter. Occasionally one spins toward Earth, and if it hits, merits the title of meteorite.

Simonson used the pointer he had been leaning on to indicate photos of a car and a women that had both been hit by small meteors. To show the more intense impact from larger meteorites, he held up a small black rock. The rock was a sample of debris from meteorite that left behind the kilometer-wide Meteor Crater in Arizona 50,000 years ago.

One of the most famous craters on Earth is Chicxulub, 10 kilometers wide and made 65 million years ago in the Yucatan Peninsula. The discovery of this important crater, left by an asteroid theorized to have wiped out the dinosaurs, is partly credited to Oberlin College graduate Antonio Camaro.

“He had been taught to think outside the box, and I hope you are, too,” said Simonson.

Meteorites explode when they hit the Earth at cosmic velocity, between 20 and 80 kilometers per second. According to Simonson, when they create a hole, half of the earth is pushed aside, and half up into space.

Simonson related his daughter’s response to the asteroid theory of the dinosaurs’ extinction:

“Oh yeah, a rock fell from the sky and hit every dinosaur on the head,” she said.

When the debris from this crater flew back down, however, it heated the surface of the Earth to about the temperature of an oven set on broil. This caused wildfires that must have cleared away most vegetation on the planet.

Half an inch of debris covered the surface of the planet, now a soot-rich layer filled with glassy spherules that Simonson studied in the two decades he spent in Western Australia and South Africa. “Teardrops” in the layer indicated broken asteroid tails while bubbles revealed that it was originally molten.

Simonson also studied a layer of banded iron formations left from deposits of mud 2.5 billion years ago. This geology proved that a lower level of oxygen existed in the Earth’s atmosphere at the time. The layer is now used for iron mining. Simonson, his wife and his young children stood by as a blast shot out enough iron to construct 40,000 Toyotas.

“They don’t do that much in America: invite your family to a mine blast,” Simonson joked.

Spherules resulting from meteorites are also found in symmetrical sand ridges. After becoming lodged in deep sea floor, a tsunami will rip them from the floor and carry them in its waves. Waves caused by one meteor were an estimated 100 meters high.

When Simonson moved from Australia to South Africa, he was granted an inch-wide layer of spherules to compare with those he had found down under. His findings pointed to both of them resulting from the same impact. He discovered spherules of the same texture and minerals formed within hours of each other 2.6 million years ago. His team had been the first to discover the African spherules.

“It was a truly sobering lesson,” he said. “For decades, geologists had not seen spherules because it was not what they were looking for.”

They matched up layers from three impacts between Western Australia and South Africa, each around 70 million years apart. Others have graded similarities in spherules from 3.2 billion years ago. This tells us that something was different in the composition of the Earth’s surface in these times, possibly that there were smaller continents or shallower oceans causing tsunamis to spread the spherules more easily.

Simonson finished by thanking the students who have helped with research and displayed his collection of meteorite debris. Professor Dan Stinebring announced that the Oberlin chapter of Sigma Psi, an international scientific research association, will be hosting two more lectures in the spring.