\ argument and UFO reports is the fact that objects have been reported to land and take off. Having arbitrarily settled on a design for a ship employing annihilation of matter for power and a horribly inefficient photon drive for thrust, Markowitz proceeds to imagine this starship entering the atmosphere of Letters a planet and landing on its surface, us- ing the full fury of its interstellar drive, a process akin to docking the Forrestal UFO Consensus I agree with Markowitz (“The physics and metaphysics of unidentified flying objects,” 15 Sept., p. 1274) that extraterrestrial control of UFO’s is unlike- ly. Nevertheless I find his arguments unconvincing. First, a minor point—he seems to imply that Hynek is inconsistent when he states that UFO’s have been seen by “scientifically trained people” but have not been seen by “trained ob- servers.” I think the distinction here is reasonably clear. In this age of lasers. superpower microwaves, and superconducting magnets, his appeal to the law of StefanBoltzmann seems curiously unimaginative. as does his dependence upon solid surfaces to deflect high-energy particles. He arrives at a power required for interstellar flight of 3 * 10" watts. noting that it is 30 times the world’s electric generating capacity. An equally pertinent comparison would be to note that it is only 300 times the power of a single Saturn V, andthat on/y a single decade of development effort separates that vehicle from its 300 times smaller predecessor! In any case. why does an interstellar vehicle need an acceleration of Ig? On the other hand, a ship for such a voyage would probably weigh much more than 5000 kilograms. So in the end, one must agree that a satisfactory interstellar propulsion system is quite beyond the capability of our present technology. But his arguments in no way prove or imply that it is beyond someone else’s—or even beyond what we will have 100 years from now. As far aS proving that interstellar flight use a specific impulse of 3 x 10" seconds to lift off the earth when 1000 seconds or less would do? In short, the use of an interstellar space ship to explore within our atmosphere seems about as likely as the use of airliners to explore the bottom of the sea. Why suggest that a 1000-year trip duration should make the voyagers anxious to meet us formally? An alternative deduction would be that another hundred years, more or less, is of little consequence to them. The fact that Columbus did not hesitate to talk to the Indians was not without consequences that were unfortunate for Eur- ope and tragic for the Indians. Per- haps our interstellar visitors have learned to be more cautious—and con- siderate. Finally, the suggestion that “hard- of physics are valid.” The non sequitur is blatant: Markowitz has proven only that his own design does not explain reports of takeoffs or landings. He has revealed his own haste to arrive at a particular conclusion. When Markowitz “assumes for purposes of discussion” the existence of technically advanced beings, one might expect that this assumption would play a part in the discussion, but evidently the implications of such an assumption have escaped his notice. A technically advanced race just a cosmic clock-tick ahead of us in achievement would not only have inconceivably advanced sci- just like observations of any other in- would drop the matter? The only valid argument against extraterrestrial visitors is, carried out with a casualness that would shock our poverty-stricken souls. It is no more possible for us to expand our minds enough to encompass what will be the truth in a thousand years than it would have been for Charlemagne to teresting phenomena, seems constructive. But why insist, on the other hand, that the Air Force should completely I believe, a statistical one. The probability of there being a civilization ad- vanced enough, near enough, and dili- gent enough to find us is simply not very high. RICHARD J. Rosa Aveo Everett Research Laboratory, 2385 Revere Beach Parkway, Everett. Massachusetts 02149 I acknowledge Markowitz’ analysis of the UFO problem, and wish him well in the next field to which he lends just as we propose to do? And why the contents of UFO reports. The one link between Markowitz’ theoretical 8 DECEMBER 1967 ports of landings andlift-offs of UFO's are not reports of spacecraft controlled by extraterrestrial beings, if the laws entific ability, but technological skill be- of the technical community to peruse, ments are simply irrelevant. His argument that the ground should be seared and radioactive where a UFO has touched down also seems irrele- vant. Isn’t it probable that such voyagers would use “excursion modules” have never been observed, Markowitz concludes, “Hence, the published re- data” cases should be published for all his attention, since he has apparently finished this one. He cannot depart quickly enough, however, to escape the objections of those he left standing amid the shambles. His entire argument against the possibility of extraterrestrial control of UFO’s rests on theoretical violates the laws of physics. his argu- by running it up onto a beach. Since the obvious results of such foolishness grounds, and bears no relationship to yond our comprehension. Such beings effectively command immense wealth; what would seem to us impossibly ambitious, ruinously expensive, and even frivolous undertakings would be speculate on the present gross national product of France, without even a word for 10°. The contrast between the notion of an advanced civilization’s mode of transport {as one may legitimately attempt to imagine it) and Markowitz’ sketchy design for a starship is ludicrous. Of course there may not de any advanced civilization, or any starships. Nobody can go beyond premise-bound speculations on those subjects, and even our speculations are denied the use of physical principles and effects that remain undiscovered. WILLIAM T. POWERS Dearborn Observatory, Northwestern University, Evanston, [linois 60201 1265