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UI's Louis Frank presents additional proof for "small comet" theory

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 each day.

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 Society.

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.

12/9/97

(For further information, see the small comets web site: http://smallcomets.physics.uiowa.edu/www/ultimate.html)