[meteorite-list] Celestial Sleuths Track Historic Meteor Procession to South Atlantic

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 23 Jan 2013 16:28:12 -0800 (PST)
Message-ID: <201301240028.r0O0SCuW016641_at_zagami.jpl.nasa.gov>

http://www.txstate.edu/news/news_releases/news_archive/2013/January-2013/Meteors012313.html

Celestial sleuths track historic meteor procession to South Atlantic
Posted by Jayme Blaschke
Texas State University
January 23, 2013

A century ago, one of the most spectacular astronomical sights ever
recorded lit up the skies when a grand procession of meteors blazed
their way through the Earth's atmosphere. The event made headlines from
Toronto to Pennsylvania and New York, and in the days that followed
eyewitness reports poured in from as far away as Western Canada and Bermuda.

Now, on the 100th anniversary of the historic event, astronomers Don
Olson of Texas State University and Steve Hutcheon of the Astronomical
Association of Queensland, Australia, have answered a long-forgotten
call for more information from the pages of the science journal
Nature, establishing a far greater range for the great fireball
procession than previously known.

Olson and Hutcheon publish their findings in the February 2013 issue of
Sky & Telescope magazine, on newsstands now.

A meteor procession occurs when an Earth-grazing meteor breaks up upon
entering the atmosphere, creating multiple meteors traveling in nearly
identical paths. Instead of plunging down through the atmosphere and
burning up within a second or two, as often observed in normal meteor
showers, the fireballs in meteor processions travel almost horizontally,
nearly parallel to the Earth's surface. Each member of a meteor
procession can remain visible to a single observer for about a minute,
and the entire procession can take several minutes to pass by.

On the evening of Feb. 9, 1913, the dazzling procession of meteors
crossed over Canada and the Northeastern United States traveling
northwest to southeast. University of Toronto astronomer Clarence A.
Chant collected accounts from the astonished eyewitnesses and
summarized, "To most observers the outstanding feature of the phenomenon
was the slow, majestic motion of the bodies; and almost equally
remarkable was the perfect formation which they retained." Hundreds of
meteors were observed as far west as Saskatchewan, Canada, around 7 p.m.
Mountain Time, and as far east as Bermuda at around 10 p.m. Atlantic
Time, a distance of more than 2,400 miles. In the years that followed,
additional reports from a town in Alberta, Canada, and a ship off the
coast of Brazil extended the confirmed range of the meteor procession to
more than 6,000 miles.

Writing about the procession in Nature in 1916, William F. Denning
observed that "Such an extended trajectory is without parallel in this
branch of astronomy. Further reports from navigators in the South
Atlantic Ocean might show that the observed flight was even greater."
Later in 1916 Denning observed in the Journal of the Royal Astronomical
Society of Canada that, according to the most distant ship sighting
known to him, the meteors "were still going strongly - and may have
pursued their luminous career far southwards over the South Atlantic
Ocean, but navigators alone, during morning watches, can give us further
information on the subject."

Olson and Hutcheon responded to the call for observations nearly a
century later. Sifting through a vast array of archival material, the
team discovered seven ship reports, all previously unknown, extending
the established track of the procession by an additional thousand miles.

"We had the most wonderful help from U.K. and German archives. By the
time they were finished, the German archivists had found six reports and
the U.K. archivists had located one more," Olson said. "We have seven
new accounts from ships' meteorological log books that extend the track
farther than ever before. This is the most complete map for this
phenomenon that's ever been compiled.

"The track now goes more than 7,000 miles--that's more than a quarter of
the way around the world," he said. "That's an almost unbelievable
meteor event!"

The search was complicated by several factors. One was that by the time
the meteors crossed all the time zones from Western Canada to reach the
ships in the South Atlantic, it was after midnight and therefore the
relevant local date was Feb. 10. Additionally, the Earth continued to
rotate beneath the meteor procession, effectively moving the track
farther west than expected if it were a simple great circle arc. But
after an extended search, the seven ships in the South Atlantic off the
Brazilian coast turned up to provide valuable data reporting the event.

"This is the most complete map ever drawn of the ground track of the
procession. The known ground track is now more than 7,000 miles long,"
Olson said. "The seven ship accounts are all newly-discovered for this
article. The archivists helped us to find new information about one of
the greatest meteor events."

Unfortunately, the ultimate fate of the spectacular meteor procession
will likely never be known.

"They disappeared into the really obscure South Atlantic, outside of the
well-traveled shipping lanes," Olson said. "We would like to locate more
reports, but we've had no luck so far finding accounts from Brazil,
islands in the South Atlantic, South Africa and Australia. But the
procession was still going strong when seen by the last ship."
Received on Wed 23 Jan 2013 07:28:12 PM PST