Student debunks famous lunar crater theory

By Mike Martin, UPI Science Correspondent

TUSCON, Arizona, April 19 (UPI) -- A second-year graduate student at the University of Arizona may have debunked a long-cherished theory about the formation of one of the moon's most famous craters -- Giordano Bruno.

Paul Withers, of the planetary sciences department, tested the consequences of a nearly thousand-year-old eyewitness report detailing a "lunar impact event" that purportedly created the Bruno crater. After months of in-depth calculations and a search of worldwide medieval writings, Withers concluded that witnesses on Earth could not possibly have seen a meteor impact the moon.

"The idea that anyone saw the asteroid impact that created this crater just doesn't hold up under scientific scrutiny," Withers told United Press International from Tucson.

The medieval scribe Gervase of Canterbury wrote the original eyewitness account of five monks who claim to have seen "the upper horn of the new moon split, and from the division a flaming torch spring up" on June 18, 1178 A.D. "The body of the moon...writhed and throbbed like a wounded snake," the report dramatically recounted.

In 1976, the astronomer Jack Hartung published a now-famous paper linking the eyewitness report to the formation of Giordano Bruno, a 14-mile-wide lunar crater that newly-available Apollo mission photos made a likely candidate for formation from an asteroid impact 8 centuries earlier. Isaac Newton himself made reference to the famous story, which Hartung labeled a singular event, never before witnessed in human history.

In his paper, "Was the Formation of a 20-KM-Diameter Impact Crater On the Moon Observed on June 18, 1178," Hartung dissects the entire 300-word Gervase report, relating each sentence to the formation of crater Bruno. Hartung used a set of 4 separate Bruno-creation criteria that seemed to fit the eyewitness observations perfectly.

Now graduate student Paul Withers claims the story is no more than a myth and he has the data to back up his claim. "Basically, an impact like the one that created Giordano Bruno would have launched 10 million tons of debris into the Earth's atmosphere in the following week," Withers said.

The half-mile to perhaps 5-mile-wide meteor that probably created Bruno would have kicked up enough dust to cause a week-long meteor shower with a density of some 50,000 meteors per hour, raining around the Earth. This meteor storm would have been civilization threatening, Withers claims, causing regional devastation and possibly global climatic catastrophe. Withers is certain no one witnessed such an event for a simple reason: while Gervase of Canterbury and five monks reported the supposed creation of Giordano Bruno, no one reported what would have been the much more spectacular aftermath.

"There are no accounts in any known historical record, including the European, Chinese, Arabic, Japanese and Korean astronomical archives, Withers told UPI.

Desert Research Institute climatologist Kelly Redmond takes issue with Withers' claims about catastrophic global climate changes, but agrees with the graduate student's assessment of the amazing meteor shower that would have followed the lunar impact.

"Any meteor impact on the moon would somehow have to put enough ejected debris into the Earth's atmosphere to affect the flow of radiation to and from the Earth's surface," Redmond told UPI from his Reno, Nevada office. "I just don't see how even 10 million tons of ejecta from the moon could have done this."

Clark Chapman, an asteroid specialist and planetary scientist with the Southwest Research Institute in Boulder, Colorado, told UPI he always found stories about eyewitness accounts of the Bruno crater formation suspect. Withers' findings only confirm his own long-held skepticism, he said.

"About ten years ago, when I was editing the Journal of Geophysical Research on Planets, we published an article that concluded massive meteor showers would have resulted from the lunar impact that supposedly created Giordano Bruno," Chapman told UPI. "Those same showers should be recurring even now, with debris left in our atmosphere from the original Bruno impact."

However, no such meteor showers occur today, Chapman said. So what did the five monks see in 1178, if not the spectacular creation of a lunar crater by a meandering rock?

"I think they happened to be at the right place at the right time to see a meteor that was directly in front of the moon that burst into flames in the Earth's atmosphere," Withers told UPI. This idea was strongly suggested by others in a 1977 scientific paper, he added.

Withers reports his analysis in this month's issue of the journal Meteoritics and Planetary Science.