Scientist Thinks Comets Created Oceans; Others Say Theory Is All Wet

A senior scientist with the Jet Propulsion Laboratory has discovered evidence that seems to support a controversial theory that the oceans were created by trillions of small, water-bearing comets plunging into the Earth’s atmosphere over the last 3 or 4 billion years.

The evidence, which consists of several hundred images of small comets taken with a specially programmed telescope over a three-month period, is the latest twist in one of the most heated astronomical debates of the last few years--and it brought immediate skepticism from the scientific community.

The evidence surprised even its discoverer, Clayne Yeates, deputy project scientist for the Pasadena lab’s Galileo Project, who emphasized that the findings are preliminary.

“I was very dubious about this whole thing,” Yeates said. “The only thing I was trying to do was to see if the objects (comets) were really there. I thought there was a good chance we wouldn’t see anything.”

Instead, he captured images of small comets at the rate of about one every minute, indicating that they are entering the Earth’s atmosphere and vaporizing by the millions every year.

That fits neatly with a revolutionary theory advanced two years ago by a team of scientists from the University of Iowa, a theory that so contradicted conventional wisdom that scientists around the world have devoted much of their efforts to laying it to rest. Until Friday, when Yeates revealed his findings through a JPL press release, they appeared to have succeeded.

“I thought this thing had died,” said David Stevenson, professor of planetary science at Caltech.

Yeates stopped short of saying his work proves that the oceans were created by comets, but he said the evidence shows that water-bearing comets, up to 30 feet in diameter, are entering the atmosphere at an enormous rate that is consistent with the theory.

The theory was first advanced in 1986 by a team of scientists from the University of Iowa headed by physicist Louis A. Frank.

Over the course of five years, beginning in 1981, Frank’s team studied thousands of observations from a research satellite, Dynamics Explorer 1, in polar orbit 14,500 miles above the Earth. The team found about 30,000 small, mysterious black spots in ultraviolet images of the Earth.

After puzzling for some time over what could have created the spots, the team concluded that the spots probably represented clouds of water vapor 180 miles above the ground that absorbed ultraviolet emissions from the Earth’s atmosphere below. The clouds, they concluded, probably came from small comets, made mostly of ice, that broke up as they entered the atmosphere.

After much soul searching, and correctly anticipating the furor that followed, Frank publicly theorized that millions of tiny comets, covered with black hydrocarbons that made them practically invisible and traveling so fast they were almost impossible to track, were bringing enormous amounts of water to the Earth every year, and probably had done so throughout the planet’s history.

One of the biggest objections to the theory came from astronomers who insisted that if that were the case, the moon would be constantly bombarded by similar comets and, since the moon has no atmosphere, the comets would arrive at the lunar surface intact, thus constantly creating thousands of new craters.

“How do you explain the fact that you don’t see evidence of this on the moon’s surface,” said JPL astronomer Don Yeomans, one of several scientists who voiced skepticism over Yeates’ findings.

Nonetheless, Yeates insisted Friday that his evidence should be taken seriously.

For his research, Yeates used the 36-inch Spacewatch Telescope at Kitt Peak, Ariz., which is particularly well suited for tracking fast-moving objects. From November through February, he programmed the telescope to follow a course across the sky that corresponded with the course the comets would be expected to follow.

“It’s like skeet shooting,” he said, referring to clay targets used by shotgun enthusiasts to simulate birds in flight.

In all, he completed 1,500 exposures of 12 seconds each.

All images showed background stars as streaks of light of equal length, because the stars moved across the field of view as the telescope tracked the anticipated course of the comets. Comets appeared as much shorter streaks of light, moving in different directions from the stars.

“We were getting one (comet) every minute,” he said.

Furthermore, the comets had the characteristics that Frank’s theory had predicted: small and dark, suggesting that they were covered with hydrocarbons that held their water in check until they broke up in the atmosphere. And they were entering the atmosphere at a rapid frequency that was also consistent with Frank’s theory.

If Frank should turn out to be right, and few scientists believe that he will, it means much of the current theory of the Earth’s evolution is dramatically wrong. For example, scientists have long believed that the oceans developed early in the history of the planet and have been evaporating slowly ever since. If Frank is correct, they developed much more slowly, and they are still growing.

It would be a precious victory for Frank, who laid his reputation on the line when he first announced the theory.

He told the Associated Press on Friday that he had “lost a lot of friends” over the controversy.

“I’m happy (about Yeates’ observations), but it’s been a long two years,” he said.