The speculation about what the green fireballs were ran through the usual spectrum of answers, a new type of natural phenomenon, a secret U.S. development, and psychologically enlarged meteors. When the possibility of the green fireballs' being associated with interplanetary vehicles came up, the whole group got serious. They had been doing a lot of thinking about this, they said, and they had a theory.

The green fireballs, they theorized, could be some type of unmanned test vehicle that was being projected into our atmosphere from a "spaceship" hovering several hundred miles above the earth. Two years ago I would have been amazed to hear a group of reputable scientists make such a startling statement. Now, however, I took it as a matter of course. I'd heard the same type of statement many times before from equally qualified groups.

Turn the tables, they said, suppose that we are going to try to go to a far planet. There would be three phases to the trip: out through the earth's atmosphere, through space, and the re-entry into the atmosphere of the planet we're planning to land on. The first two phases would admittedly present formidable problems, but the last phase, the re-entry phase, would be the most critical. Coming in from outer space, the craft would, for all practical purposes, be similar to a meteorite except that it would be powered and not free-falling. You would have myriad problems associated with aerodynamic heating, high aerodynamic loadings, and very probably a host of other problems that no one can now conceive of. Certain of these problems could be partially solved by laboratory experimentation, but nothing can replace flight testing, and the results obtained by flight tests in our atmosphere would not be valid in another type of atmosphere. The most logical way to overcome this difficulty would be to build our interplanetary vehicle, go to the planet that we were interested in landing on, and hover several hundred miles up. From this altitude we could send instrumented test vehicles down to the planet. If we didn't want the inhabitants of the planet, if it were inhabited, to know what we were doing we could put destruction devices in the test vehicle, or arrange the test so that the test vehicles

They continued, each man injecting his ideas.

Maybe the green fireballs are test vehicles--somebody else's. The regular UFO

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