The dinosaurs became extinct because a giant asteroid hit the earth, right? Not so fast earth sciences professor Jason Moore says that the object that hit the earth 65 million years ago was more likely a smaller, speedier comet. Moore worked with a team at Dartmouth to find significant evidence against the seemingly fundamental asteroid hypothesis, one we have accepted since we first learned that dinosaurs existed and then realized they were no longer walking around outside.
Actually, don't be too quick to draw the conclusion that the asteroid I mean comet! actually eliminated dinosaurs from the earth either. Moore pointed to the birds flying outside as examples of living manifestations of the prehistoric creatures.
"All dinosaurs did not go extinct," he said. "There's another disagreement in the scientific community at the moment as to how important the impact was. Some people suggest that in fact the impact killed all the dinosaurs. I'd say that there is still no resolution."
Moore wasn't expecting to find himself engaged in research that would fundamentally challenge the cause of the 180 kilometer-wide Chicxulub crater in Mexico that is normally attributed to the extinction of the dinosaurs. Indeed, he's more likely to be looking at the fossils of the dinosaurs that still lived after the comet hit the earth.
"Research-wise, I'm primarily a paleoecologist interested in interactions between organisms and the environment in the past," Moore said. "Most of my research looks at how communities of organisms react to major changes, be it a giant meteorite or comet impact, climate change or the introduction of new species."
Perhaps it was exactly the fact that this research was beyond Moore's field that allowed him to entertain and explore the groundbreaking idea that something other than an asteroid created the Chicxulub crater.
"We were coming from the outside," Moore said. "Because we didn't have a horse in the race, we could come in without any immediate idea of what was going on and address all possible solutions equally."
The findings rocked the scientific world. A recent BBC article was the first to publicize the Dartmouth team's comet hypothesis after Moore, along with his team of geography professor Jonathan Chipman, earth sciences professor Mukul Sharma and Hannah Hallock GR'12, presented their findings at the 44th Lunar and Planetary Science Conference in the Woodlands, Texas, in March.
Naturally, the comet hypothesis sparked controversy.
"There was a brief period in early '90s where people were flirting with the comet idea, but that faded out, and we're the resurgents of that idea," Moore said. "I think we've got a really good case for this. There are geophysicists who would disagree. We're arguing in the face of 30 years of work."
When interacting with the asteroid die-hards, Moore said he and his team appreciated the criticism but remained convinced of their theory. No one ever said the experts were always right everyone makes mistakes, and that can go both ways.
"As a scientist, you have to let the data speak for itself," Moore said. "We didn't come into this with a particular set of biases. We hadn't looked at the data before. We looked at a range of possibilities, but in the end it fell out very strongly in favor of it being a cometary impact."
What findings exactly led them to this conclusion? The simple story is this: something hit the earth 65 million years ago in Mexico. Whatever it was left a layer of sediment over the earth enriched with concentrations of iridium that are higher than is natural on our planet. Hence, this something must have been from outer space. Previous research on the amount of iridium deposited estimates that more iridium was deposited than actually was. While previous iridium estimates pointed to a big asteroid, only something smaller, like a comet, can account for the lower amounts of iridium found.
Despite the attention that Moore received last month at the conference, he admitted that it was "slightly strange" for him to be there as a paleontologist.
"I feel like I was regressing to my undergrad days where you don't know anyone and feel out of your element," he said.
Indeed, it must be strange for someone whose office shelves are filled with fossils of extinct creatures to find himself among those whose careers have revolved around researching the moon and planets.
While Moore might feel out of place at a lunar and planetary meeting, he can tell you just about anything about his fossils on the spot. Selecting one of the many sleek skulls from his shelves, Moore informed me that it had been preserved in its state for 33 million years.
"I hope I look that good when I'm 33 million years old," he joked.
Perhaps it's Moore's playful nature that allowed him to entertain ideas outside the conventional wisdom and launched him into what he describes as "one of the most controversial research projects I've directly presented before."
His discovery may help inform his primary research interests. Moore said that knowing for sure whether the impact was caused by a comet or an asteroid could help to resolve some of the inconsistencies between the dinosaur species that went extinct and the ones that didn't.
"We hope people will start thinking in that direction," he said.
Moving forward, Moore's work will extend beyond Dartmouth as he moves to a position at the University of New Mexico.
Moore said one of his favorite aspects of Dartmouth has been the opportunity to teach "students who are interested and motivated" at the graduate and undergraduate level.
"I've loved every second of teaching I've done here," Moore said. "Don't tell my colleagues, but some of the undergraduates I've taken to the field were putting the graduate students of my colleagues to shame."
New Mexico will provide a research field in Moore's backyard, where he will physically interact with the fossils that interested him.
"New Hampshire isn't known for its dinosaur fossils," Moore said. "Being able to go out and collect data on the weekend will be amazing."
Moore said that inspiring others through his research to be one of the most rewarding parts of his job. When BBC saw the potential impact of his team's findings on his comet hypothesis, Moore saw the opportunity to publicize the project and inspire the community of earth scientists.
"I'm happy that it managed to get the audience it did," Moore said "Anything I can do to enthuse the next generation about science is awesome."
