On Thursday, Brother Guy Consolmagno gave a talk at the University of Arizona about how scientists embrace contradictions of their findings in the interest of furthering knowledge.
On Friday, Consolmagno tested that premise as he presented evidence that contradicted his own 40-year-old conclusions and those of a NASA space mission that characterized the giant asteroid Vesta as an intact protoplanet just two years ago.
Mark Sykes, director of Tucson-based Planetary Science Institute and a member of the science team on NASA’s Dawn mission to Vesta, said Consolmagno presented a convincing argument that the initial science conclusions may be wrong.
“That’s life,” he said. “Science things change. You’ve got to be open to new evidence.”
Sykes wasn’t entirely convinced, however, that Consolmagno’s proposed explanation would withstand future scientific scrutiny.
Consolmagno, with an international team of scientists organized by Diego Turrini through the International Space Science Institute of Bern, Switzerland, argue that the Dawn’s own observations show that Vesta, the second-largest asteroid in the inner solar system, must have collided and reformed sometime in the past.
It is not, they argue “an intact protoplanet” that dates back to the time of the formation of the solar system.
“What we see today is a body that has been ripped apart and put back together,” Consolmagno said at a news conference held by the Division for Planetary Sciences of the American Astronomical Society, which held its annual conference in Tucson this week.
Consolmagno, was given the Carl Sagan Award at the conference for his skill in communicating science to the public.
Consolmagno is a Jesuit brother, who has worked as a Vatican astronomer and recently took a post as director of the Vatican Observatory Foundation.
Consolmagno said his recent study contradicts work he did as a graduate student at the University of Arizona Lunar and Planetary Lab with the late Mike Drake.
They had argued then that Vesta was a protoplanet and the source of a class of basaltic meteorites known as the Howardite-Eucrite-Diogenite (HED) clan.
Consolmagno said Dawn’s investigation of 80-kilometer deep craters on Vesta’s surface shows it lacks the deep olivine mantle that would be necessary to be the HED mother lode.
He proposed that Vesta may have been stripped of its mantle by a massive collision with another body, while somehow keeping its iron core and HED crust. “Am I crazy?” he asked.
“Maybe it’s something completely weird like that,” said Sykes, “but to have an entire layer stripped off — does that work?”
David O’Brien, of the Planetary Science Institute, co-authored four papers on the Dawn team’s findings that appeared in the journal Science in May 2012.
“Guy raises some interesting points that challenge the conventional interpretation of Vesta’s history,” he said in an email.
“Even if it turns out they can be addressed, asking questions like that leads to a more robust understanding in the end.”