Maybe the green fireballs are test vehicles--somebody else's. The regular UFO reports might be explained by the fact that the manned vehicles were venturing down to within 100,000 or 200,000 feet of the earth, or to the altitude at which atmosphere re-entry begins to get critical. I had to go down to the airstrip to get a CARCO Airlines plane back to Albuquerque so I didn't have time to ask a lot of questions that came into my mind. I did get to make one comment. From the conversations, I assumed that these people didn't think the green fireballs were any kind of a natural phenomenon. Not exactly, they said, but so far the evidence that said they were a natural phenomenon was vastly outweighed by the evidence that said they weren't. During the kidney-jolting trip down the valley from Los Alamos to Albuquerque in one of the CARCO Airlines' Bonanzas, I decided that I'd stay over an extra day and talk to Dr. La Paz. He knew every detail there was to know about the green fireballs. He confirmed my findings, that the genuine green fireballs were no longer being seen. He said that he'd received hundreds of reports, especially after he'd written several articles about the mysterious fireballs, but that all of the reported objects were just greenish- colored, common, everyday meteors. Dr. La Paz said that some people, including Dr. Joseph Kaplan and Dr. Edward Teller, thought that the green fireballs were natural meteors. He didn't think so, however, for several reasons. First the color was so much different. To illustrate his point, Dr. La Paz opened his desk drawer and took out a well-worn chart of the color spectrum. He checked off two shades of green; one a pale, almost yellowish green and the other a much more distinct vivid green. He pointed to the bright green and told me that this was the color of the green fireballs. He'd taken this chart with him when he went out to talk to people who had seen the green fireballs and everyone had picked this one color. The pale green, he explained, was the color reported in the cases of documented green meteors. Then there were other points of dissimilarity between a meteor and the green fireballs. The trajectory of the fireballs was too flat. Dr. La Paz explained that a meteor doesn't necessarily have to arch down across the sky, its trajectory can appear to be flat, but not as flat as that of the green fireballs. Then there was the size. Almost always such descriptive words as "terrifying," "as big as the moon," and "blinding" had been used to describe the fireballs. Meteors just aren't this big and bright. No--Dr. La Paz didn't think that they were meteors. Dr. La Paz didn't believe that they were meteorites either. A meteorite is accompanied by sound and shock waves that break windows and stampede cattle. Yet in every case of a green fireball sighting the observers reported that they did not hear any sound.