Christmas, Carl Sagan, and extraterrestrials

        At this festive season, what topic could be more appropriate for this blog than Carl Sagan's 1977 Christmas lectures at the Royal Institution in London?

        In my previous blogpost I insisted that Carl Sagan may have theorized a possible 10,000 visits to Earth by ETs in his 1962 paper, but he certainly did not hold that opinion for very long. I made reference to his Christmas lectures for support of that proposition, and I'm about to give chapter and verse on that.

        The overall title of the six-lecture series was "The Planets," and it was Carl Sagan at his best--urbane, charming, fluent and full of good information. The R.I. demonstrators were at their best too, providing excellent models and other visual aids to make this sometimes difficult subject accessible. In the last lecture, titled Planetary Systems Beyond our Sun, Sagan started by talking about techniques for detecting exoplanets. Today those techniques have been refined but the general principles are still the same. He talked about the Drake equation, as a way of estimating how many intelligent civilizations there are in the galaxy, and then embarked on an analysis of how radio contact might be established. This included an intriguing demonstration of how a three-dimensional model of a formaldehyde molecule might be transmitted as a message of 29,791 binary digits. The intent of such a message, he said, might be to direct our attention to the natural frequency of formaldehyde where a more elaborate message would be found. He then went on to say this:

47:55 One often comes upon some other ideas about extraterrestrial intelligence -- namely, why go to all this trouble with radio telescopes when the extraterrestrials are already here? We sometimes hear something like that. The ideas are often expressed in terms of unidentified flying objects, and in terms of ancient astronauts. Now there's nothing silly about being able to fly between the stars. We are already doing it although at an extremely slow pace. It's taking us about 80,000 years to go from here to the nearest star with our present space vehicles. But other civilizations more advanced than we might very well be able to do it in much shorter periods of time--so maybe we are, or have been, visited. It's not ridiculous. On the other hand, it's such an important contention that we should demand only the most rigorous standard of evidence. And my judgement is that on the ancient astronaut business what happens is people look at big buildings constructed long ago and say "My goodness, I don't know how that big building was built, probably people from somewhere else built it." Yes--maybe from Egypt, but not from some other star. These ideas often show an ignorance of archaeology--our ancestors were smart, they could build big. There's no artifact in early human history, so far as I know, which requires extraterrestrial intervention.

Likewise, on unidentified flying objects, there are things seen in the sky which are unidentified--that's what an unidentified flying object is, it means we don't know what it is. It doesn't mean it's a space vehicle from somewhere else. And there ought to be things in the sky that we don't understand--the sky is very rich in phenomena--astronomical, meteorological, optical and man-made phenomena. And therefore only a very reliable sighting of an extremely exotic object ought to be considered in any way relevant to our problem of life elsewhere.  And to the best of my knowledge, there are lots of exotic reports, but none of those exotic reports are reliable. For example, a 30-foot diameter metallic shaped object lands in a suburban garden. A seamless door opens. A metallic robot walks out, picks a flower, smells it, pets the cat, waves to a lady hiding behind her sliding glass door, turns on his heel, enters the UFO, the seamless door closes and it takes off into space. Now that I would call an exotic story--no question about it. But when we look closely into that, it turns out no-one in all of Long Island, New York City, besides the old lady noticed that this had happened. And the cat was unavailable for corroborative evidence.  And that's an example of an exotic story that isn't reliable. On the other hand there are reliable stories, lots of people see something, that are not exotic--a light in the sky. There are no cases where 200 people see something as exotic as what I just said, no cases where there's a piece of the spacecraft that someone captures and sneaks into a laboratory so they can investigate it. No-one has ever managed to steal the captain's log book. And until that sort of thing happens, it seems to me we must be very cautious and skeptical because extraordinary claims require extraordinary evidence. It would save us a lot of trouble if those fellows  would come here, instead of us having to go out and find them. I'm not opposed to it--it's just that there isn't a smidgen of good evidence to support those ideas. I wish it were otherwise. 

It's very unlikely I'll be blogging again until 2017, so best wishes to all.