Sirs:
"Have We Visitors from Space?" (LIFE, April 7) is the most comprehensive report I have read on the subject. I was very closely associated with Projects "Twinkle" and "Grudge" at Alamogordo, N. Mex. where I was chief of the technical photographic facility at Holloman Air Force base. I have seen several of these objects myself, and they are everything you say they are as to shape, size and speed. 

Daniel A. McGovern
Captain, USAF
Alexandria, Va.

Sirs:
I first learned about the green fireballs from Marine Corps night fighter pilots while I was an aviation intelligence officer in Korea.

Sirs:
LIFE has again rendered a distinct service to its readers. The authors' painstaking work in compiling and evaluating known data has made a case for interplanetary space ships which is entirely logical and sensible.

Donald J. Falvey
Deep River, Conn.

Sirs:
As observers of the Lubbock lights, we feel the record requires that we point out that the groups of objects shown in the Hart photographs are, in these respects, essentially different from any of the 12 or more groups that we sighted.

1. All but three of the groups we sighted had no geometric form; those three were smooth arcs, not V-shaped.
2. Those three could not be conclusively determined to be composed of individual lights, but certainly they were not made up of two distinct rows of alternately spaced lights.
3. None of our sightings was either bright enough, nor in view long enough (3 seconds) to offer any possibility of being photographed.
4. Even if the lights we saw had been particularly rich in nonvisible ultraviolet light, they could not have been photographed without special equipment.
5. All of our sightings were close to the same speed of 30 degrees per second, at which speed it would be impossible to follow them with a camera accurately enough to obtain an unblurred image.

           W. I. Robinson
           A. G. Oberg
           W. L. Ducker
           E. F. George
           Lubbock, Texas

• Air Force experts had considered these objections of Professor Ducker and Doctors Oberg, Robinson and George. But they are still convinced that Hart was able to get exposures of the two groups he saw (4 seconds for each to cross the sky, 1-11/2 minutes apart) and found no reason to repudiate his pictures. — ED.

Sirs:
Your article overstates the strangeness of the fireballs it describes...

C. C. Wylie
Professor of Astronomy
University of Iowa
Iowa City, Iowa

• Although there were meteor falls during this period, Dr. LaPaz says: "Almost all of the green fireballs observed in the Southwest between December 1948 and December 1951 radiated from the circumpolar region of the sky. They came from points 35 to as much as 105 degrees distant from the Taurid fireball radiant, and therefore obviously were not related to this radiant." — ED.

Sirs:
It is rather chilling to see that our plans for hospitality include interceptions and recovery. It would be tragic indeed if the harmless and friendly behavior of these crafts from elsewhere were met with military destruction. Not only would the morals of such a course be a regrettable indication of man's immaturity, but the practical consequences might include drastic reprisals....

Mason Rose
Los Angeles, Calif

Sirs:
... The only reason the preponderance of this saucer-fireball-cigar activity is taking place in the American Southwest is that this is the area which has brought itself to interplanetary (or perhaps I should say, intergalaxial) attention. It was done so by virtue of the fact that it was the site used for the original A-bomb experiments....

Bill Ryan
San Diego, Calif.

• The Air Force, which has attempted to correlate the frequency and location of saucer reports with the testing of atomic weapons, has found no significant relationships. — ED.