Student may debunk lunar crater theory


 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 Arizona's planetary sciences department, tested the
consequences of an 800-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.

 As he reports in the current journal Meteoritics and Planetary Science,
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 of impact debris arriving on Earth.

 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
22-kilometer-wide (14-mile-wide) lunar crater that newly available Apollo
mission photos made a likely candidate for formation from an asteroid impact
eight centuries earlier. Isaac Newton himself had 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 dissected the entire 300-word
Gervase report, relating each sentence to the formation of crater Bruno.
Hartung used a set of four 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 kilometer to perhaps 8-kilometer-wide (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. The meteor storm would have
threatened civilization, Withers claims, causing regional devastation and
possibly global climatic catastrophe.

 Yet "there are no accounts in any known historical record, including the
European, Chinese, Arabic, Japanese and Korean astronomical archives,"
Withers told United Press International.

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

 "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, said Withers' findings
confirm his own long-held skepticism.

 "About 10 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 space 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.

 (Reported by UPI Science Correspondent Mike Martin in Washington)
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