"It's like the early 1900s with the appearance of Halley's Comet all over again," she said. "People were terrified because they thought we'd pass through the tail. Disreputable people were selling comet pills to ward off terrible effects, which is nonsense."

The gas tail is blue because of carbon and nitrogen molecules, but there is probably more gas accidentally in the Earth's atmosphere than people would encounter with the comet, Meech said.

"Nevertheless, people were terrified. To me, we're 90 years in the future and people ought to be a little more sensible."

The amateur astronomer who started the UFO commotion last November used a software program incorrectly in bringing up a chart of the sky, she said.

"Accidentally, it did not show bright stars. So when he compared his photograph of the comet to the star chart, sure enough, the bright object in the sky was not on his chart." Instead of considering that he made a mistake, "he leaped to the conclusion this was a UFO."

Many people also using sophisticated electronic detectors who don't know how to interpret artifacts or strange features showing up on the digital images, she said. More than half a dozen things can cause them, she said, such as dust on the mirror and in the optics.

She said Olivier Hainaut, postdoctoral fellow working with her, spent a lot of time on a UH Internet page explaining what the digital images really were in hopes UH wouldn't be flooded with questions. But she said, "Sometimes these people really want to believe there are UFOs and no amount of logical argument is going to convince them otherwise."