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The Search for Extraterrestrial Intelligence (SETI) in the

Optical Spectrum


Fred Johnson: I'd like to address Drake's famous equation and the probability of solar systems being out in the galaxy. I think Drake was overly conservative. I think that the statistics to be totally different. Let me show you a bit of information. All astronomers know this particular curve which shows you the rotation rate of stars as a function of spectral class. It is something of an "S" curve with the F spectral class being in the middle and the G, K and M being at the very bottom. The difference is two orders of magnitude. The O, A and B type stars have a very high rotation rate relative to the G, K and M. Our sun is a G2, and the question is - it's a dilemma for the sun - how come the sun does not have the angular momentum? The angular momentum is associated with the major planets. It's a dilemma that I'd like to address.

I believe that - it's a surprise I'd like you to be aware of - that we may not really understand the origin of the solar system. There may be a completely different model out here. According to my thinking, I can reproduce Bode's law with a very simple model. Bode's law is the conservation of angular momentum, just given very simple assumptions. If that's the case (I may not be correct there - but, if I am correct in my interpretation), all stars go through a certain evolutionary process. The O, A and B are very young, yet they rotate very fast. Once they got to be G, K and M, they have lost their angular momentum because they have produced a solar system. If this interpretation is correct, then: 98% of the stars are G, K and M in our galaxy. So the probability of having solar systems out there is very high!

Now, the next question you might ask well, "Would they have planets?". I mention Bode's law, which gives you the relationships of the distances of the planets. If my model is correct, then my answer is "Yes, you would have planets out there at those distances". Would there be one planet that is at the distance which is like the Earth? Yes, I think so. I think there ought to be at least one at the distance where you have liquid water. That's the basis for life! Mars is too far away, and Venus is too close. All you need is just one planet at the correct distance.

Now, that changes the odds - I think - quite a bit for our discussion here. This would make it much more likely that there are planets out there. Another thing I'm going to say which is not controversial, the above is controversial, but the following is fact. My theory is still not accepted - not very well known yet.

However, consider this. The laws of physics are universal. Nobody ever questions them. Therefore, the laws of chemistry are universal; they are based on physics. Nobody ever challenges that either. Biology, based on chemistry; well, we don't know. We don't know what kind of biology we have out there because there are so many variables. The chances are that there is an enormous amount of chemistry in the galaxy. We now have a lot of evidence for this. Evidence from the interstellar medium and dust shows some of the other molecules that are seen - at least 50 molecules of miniature type. They are all seen to have the signature of organics in them. The evolution of molecules and planets so strongly suggests that there is a system out there that is driven to produce the possibility of life. At least the conditions for life are there. Whether there is any life - well this of course is what the whole thing is about. But at least the conditions are there.

Nature is very prodigious. Remember when animals breed, when the salmon breed, they produce a lot of eggs, just to get a couple of salmon out of there. I think nature might have done the same thing (throughout the galaxy). Things are overly abundant. The chances are that we are being bombarded with comets which have organics on them often enough. Many times, I think there is redundancy built in so that life might have started more than once in many more places. I think that we are kind of vain to think that we are alone, almost the same kind of thing as - I hope that I'm not treading on too many people's toes to say this: In the middle ages, we thought we were in the middle of everything. Then there was a big shock when we found out in the 1920's that our sun was not the middle of the galaxy, but somewhere in the boondocks. Now we are considering that - well - we are not alone! I think the time is ripe - the time is exceedingly ripe.

About messages, let me make one controversial statement here. We do have messages from a long time ago. Let me mention one that is unchanged that all of you are familiar with. We never thought about it as a message - the Bible. It was written at least 2500 years ago, maybe 3000 years. This gets back to the comment "Can we read the messages?". Are the messages in the bible as written down the same as we read them today? The answer is No! I've now looked at it in detail, and this is really another shock for you. There are at least half a dozen words in the Bible that we are not sure of their meaning. We lost the meaning from 2500 years ago. There are whole sentences in there that may have double meanings of which the double entendre is very subtle. I don't want to get into this now, but if you are interested, I will be happy to explain it to you some of these passages that I think have lost their meaning and had a different intent at the time. So here we have a message from human beings a long time ago, where we are not even sure of some of the messages. An interesting thought to consider. Thanks.

Charles Townes: OK. Barney, would you like to comment?

Barney Oliver: I would like to offer a comment on this rotation curve that you have produced: At the original 1961 SETI conference held at Green Bank (yes, that curve), Su-Shu Huang was present and offered that as a meaningful criterion for the selection of stars that might have solar systems, the idea being that the ones that had the low rotation rates in the primaries had planets around them and lost some of the angular momentum to the planets. That has fallen into discredit. I am not the person to tell you exactly why, but astronomers no longer think that that's a very meaningful criterion. Perhaps it has to do with the fact that even if you suggest that the globule out of which a star forms is only partaking of the rotation of the galaxy itself, it will end up with something like 100 to 200 times the angular momentum of an entire planetary system. It has to shed a lot more angular momentum than just its planets in the process of forming a star. Whether it has planets or not is not consequential.

Charles Townes: Other comments?


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