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UI's Louis Frank presents additional proof for "small comet"
IOWA CITY, Iowa -- Two University of Iowa space physics researchers today,
Tuesday, Dec. 9, presented a new study based upon photographs taken by cameras
aboard NASA's Polar spacecraft as further proof of their 11-year-old theory
that thousands of house-sized ice comets disintegrate in the Earth's atmosphere
Louis A. Frank and John B. Sigwarth presented the study at the fall meeting
of the American Geophysical Union (AGU) in San Francisco. The study shows
dark spots (called "atmospheric holes" because of their appearance
on film) captured in NASA photographs decrease in size and number as the Polar
spacecraft's altitude and distance from the holes increases -- just what one
would expect to find if the cameras are taking pictures of a real phenomenon.
According to Frank, skeptics of the small comet theory who have maintained
that the atmospheric holes are caused by electronic "noise" affecting
the camera will now have to re-evaluate their position.
"This result is a marvelous confirmation of the reality of atmospheric
holes," says Frank, a Fellow of the AGU and of the American Physical
The latest study examines June 1, 1997 photographs of the Earth's upper atmosphere,
comparing one set of pictures taken from between 3 and 5 Earth radii above
the surface to another set taken at altitudes of between 5 and 8 Earth radii.
A total of 5,650 atmospheric holes were observed in the images, however the
high altitude photographs showed an 80 percent drop in the frequency of atmospheric
holes in comparison to the low altitude data. Also a greater number of atmospheric
holes were photographed during early morning hours than during evening hours.
At the spring AGU meeting in May, Frank revealed a series of photographs
taken by cameras aboard NASA's Polar spacecraft as proof of the existence
of the 20-to-40-ton ice comets that, over the age of the Earth, could have
provided enough water to fill the oceans and plant the seeds of life. The
pictures ranged from one of a small comet the size of a two-bedroom house
disintegrating some 5,000 to 15,000 miles above the Atlantic Ocean to an image
of light emitted by the breakup of water molecules from a small comet less
than 2,000 miles above the Earth. Frank and Sigwarth, who co-discovered the
small comets and designed the three Visible Imaging System (VIS ) cameras
aboard the Polar spacecraft, said the pictures proved the existence of the
small ice comets, but some doubters remained. (Since then, a satellite trailing
the Space Shuttle Discovery in August detected significant amounts of high-altitude
water vapor, a finding that supports the small comet theory.)
"Despite all of the evidence that the atmospheric holes were a geophysical
phenomenon and not an artifact of the camera, many members of the scientific
community refused to accept the reality of the atmospheric holes because of
the immense implications of the large fluxes of small comets in the vicinity
of our planet," says Frank.
Frank first announced the small comet theory in 1986, after examining images
recorded in photographs taken by NASA's Dynamics Explorer 1 spacecraft. A
specially-made camera had been designed to take pictures of the northern lights,
a mission it completed successfully when it captured the first images of the
complete ring of the northern lights from above the north pole. But some of
the images contained unexplained dark spots, or atmospheric holes. After eliminating
the possibility of equipment malfunction and numerous other explanations,
Frank and Sigwarth concluded that the atmospheric holes represented clouds
of water vapor being released high above Earth's atmosphere by the disintegration
of small ice comets.
They calculated that about 20 comets enter the atmosphere each minute. At
that rate, the steady stream of comets would have added about one inch of
water to the Earth's oceans every 20,000 years -- enough to fill the oceans
over billions of years. The theory was immediately controversial, with people
asking why such objects hadn't been observed previously. Frank countered that
not only their small size -- 20-to-30-feet in diameter -- makes observation
difficult, but also that water striking the upper atmosphere glows very faintly
as compared to the bright glow of metal and rock in solid meteors.
Not until the 1996 launch of Polar, with its two sensitive visible light
cameras and one far-ultraviolet light camera, was there a chance to photograph
the small comets with greater resolution.
(For further information, see the small comets web site: http://smallcomets.physics.uiowa.edu/www/ultimate.html)