Documents / Hearing transcript
This is the printed record of a July 29, 1968 symposium on unidentified flying objects held by the Committee on Science and Astronautics of the U.S. House of Representatives, chaired by Rep. J. Edward Roush. The committee heard statements from six scientists: J. Allen Hynek, James E. McDonald, Carl Sagan, Robert L. Hall, James A. Harder and Robert M. L. Baker. It also printed papers from Donald Menzel, Stanton Friedman, Frank Salisbury and others. Hynek argued that puzzling UFO reports from competent witnesses deserve serious scientific study.
“Nevers”43 pages
90 I should first emphasize that the distances between the stars are absolutely huge. Light, faster than which nothing can travel, takes 4 1 / 2 years to get from here to the nearest star. Mr. Rousx. Excuse me, isn't that a rather arbitrary statement? Dr. SAGAN. I don't think so. Perhaps you can tell me why you think it might be, then I can tell you why I think it isn't. Mr. ROI7SH. In my opening statement I referred to the new audacity of imagination John Dewey had spoken of. I'm thinking of imagina- tive terms, not factual terms. Dr. SAGAN. Let me say in a sentence, why most physicists believe no material object can travel faster than light. That takes us into ques- tions of the theory of relativity, which has had previous encounters with congressional committees, and perhaps we don't want to go into that in very great detail. But the essential point is that in making a few, very few assump- tions, one of which was, the one we are talking about, nothing goes faster, Einstein was able to then derive a whole body of predictions which are confirmed in vast detail. Therefore, if someone says that is not a good idea, that things can travel faster than light, then they have to come up with a physical theory which explains everything we know in a way that is consistent with the idea that you can travel faster than light. No one has succeeded in doing that. Many physicists, have tried. Therefore,the present belief is that you can't. But that, of course, is a time-dependent statement. It may be that this isn't the ultimatetruth. In physics, as in much of all science, there are no permanent truths, There is a set of approximations, getting closer and closer, and people must always be ready to revise what has been in the past thought to be the absolute gospel truth. If I might say, to revise opinions, is one which is frequent in science, and less frequent in politics. [Laughter.] Dr. SAGAN. So ' in the context of contemporary science, I'm obviously speaking in that context, one cannot travel faster than light. So the distances between the stars are extremely large. Of course, any contemporary space vehicle would take a ridiculous amount oftime to get from here to anywhere else,. but we are not talking about contemporary space vehicles. The queston,"Is there any conceivable method of traveling from one place to another very close to the speed of light, and therefore get reasonable transit times?" involves extrap- olations of technology of a very difficult sort. However, let me merely say at least some people who have looked into the subject have con- cluded that it is not out of the question, even with contemporary principles of science, to imagine vehicles capable of traveling close to the speed of light, between the stars. This doesn't mean that it happens. There may in fact be insuperable engineering difficulties we don't know about, but there is nothing in the physics that prohibits interstellar space flight. So any estimate of how likely it is that we would be visited by an extraterrestrial intelligent civilization, depends not only on how many of them are there, but on what kind of transport they have, and how often they launch their space vehicles, even very optimistic estimates for all these numbers, gives a conclusion that an advance civilization comes here very rarely. But I again emphasize the great uncertainty in any of these numerical estimates, as they involve parts of science we don't know very much about.
Hearing transcript, from the govinfo collection. The PDF is mirrored here; the original link is under it. 256 pages are in the text index: search them above, or from the library's search.