These messages will continue. They will come rather slowly. That is unavoidable since I am traveling, giving lectures, writing a book on my area of expertise, and continuing various mathematical research projects. You are welcome to reply to my messages, or not reply, as you wish. I will post any replies that I receive from you. That is just a simple courtesy.

         My promised message about Gerald Feinberg and his ideas concerning how life might come to exist in oceans on Ganymede, Callisto, and Europa will come soon. The situation as it stands is exceedingly unfair and I want to make an attempt to help remedy it. I actually feel that it is my obligation to do that.

         I am not impressed by your attempt to dismiss the work of Feinberg and others by twisting things around so that only Hoagland could possibly have all the pieces to the puzzle, as you put it. Your "reasoning" and your version of history are absolutely wrong. It is extremely small of you to even take that stance.

         This message will primarily concern the same issue as my last - Hoagland and the idea that an ocean exists on Europa. Most of the points that you mention in your last message are answered rather fully in my article "The origin of this page." I don't feel it necessary to repeat everything.

         But the problem remains, and it is this. There is a widely-believed myth that Hoagland was the first to propose the idea that an ocean exists on Europa, and that he was therefore far in advance of the scientific community on that idea. That myth has been around for a long time, at least as far back as 1993. This I know because Jonas Angstrom told me that it was one of the factors in his decision to give Hoagland an Angstrom medal, and that occurred in 1993.

         I also know that the myth still exists to this day. My articles about Europa, and the small amount of publicity they have received, have made a difference, but they have not solved the problem. The couple of pages on the Enterprise Mission website where one can find some reference to Cassen, Peale, and Reynolds have made little difference. They are just whispers in a corner, and rather begrudging, distorted, and late-coming at that.

         Several months ago I had a brief e-mail exchange with a noted science journalist. He told me that he had believed (before I contacted him) that Hoagland was the originator of the idea that Europa might have an ocean because "everyone" said that was so, even some NASA scientists as he recalled. Putting aside the issue of blame, it is Hoagland's responsibility to do what he can to correct the problem. My last message proposed something concrete that he can do (or you, on his behalf). It is not a perfect solution, but will make a substantial difference, much more than my own efforts can. It is probably the most that one can hope for from Hoagland.

         Mr. Bara, "europa.html" is not the cause of the myth. That would be difficult to trace. But that page has many links to it, both from within the Enterprise Mission website and from other sites. Also, anyone who wishes to read Hoagland's article The Europa Enigma will probably come to it by the internet and read "europa.html" first. It has misled people in the past. I document that on my website. As it stands, it simply perpetuates the myth and continues to mislead people. If it is drastically revised, as I have urged in my last message, then it can help to eliminate the myth. This would work if the revisions are made with complete fidelity to the history as it can be documented by the papers and the articles written at the time, which are available in any university library. You continually distort this history, and state things which are factually incorrect. I suppose that you are just repeating what you hear from Hoagland.

         The myth is wrong. Richard Hoagland contributed nothing to the idea that an ocean might exist on Europa. All that he did was express his amateurish opinion that the theories about the existence of such an ocean were correct. He gives reasons for his opinion in The Europa Enigma. They are unsound reasons, and would not even convince scientists today with the much better photos now available. However, he did contribute to popularizing the idea and he did base his speculations about life on the idea, both of which are worthwhile contributions.

         I do not understand why it is relevant how well-known the idea was at the time. That would not change the fact that Hoagland was not the originator of the idea. I have mentioned in the past that it was a rather well-known idea, enough to spur speculation about life by a number of people. I feel that I have stated my point clearly enough (e.g. in my historical article) and that it is borne out by the examples of such speculations which I found. Other examples exist too. Richard Grossinger (who wrote the introduction for The Monuments of Mars) mentions such speculations by scientists in his book The Night Sky (published in 1981), but he could not recall any details when I asked him about it and I never was able to trace it down myself.

         Many people did know about the idea, and in some cases, even the scientific literature behind it. I don't mean that everyone knew it. For example, if I recall correctly, I did not know about it at that time. For another more relevant example, it is obvious from his Toronto Star article that Terence Dickinson was unfamiliar with the idea until Hoagland told him about it, as you have stated. In fact, that is a pretty sad case about which I will say more below.

         But Isaac Asimov knew about the idea and mentions it in his book Extraterrestrial Civilizations, published in 1979. Duncan Lunan and his fellow members of ASTRA in Scotland knew about it in the mid-1970s. Gerald Feinberg knew about it in early 1979 and refers specifically to the work of Consolmagno and Lewis in his book Life Beyond Earth (co-authored with Robert Shapiro, published in 1980).

         The Voyager II scientists knew about the theory and the scientific literature about it. They discuss the theory at length in their article about the Voyager II mission which appeared in Science (November, 1979). They discuss the cracks. They discuss the dark stains around the cracks, suggesting that they may be due to fluids which came up from below at some time in the past.

         The National Geographic article about the Voyager mission (January, 1980) and the NASA publication Voyage to Jupiter both mention the theory, offering it as one possible explanation of the observational data concerning Europa.

         These articles are describing what the scientists were thinking at the time of the Voyager mission. Steven Squyres also states that the theory of an ocean on Europa was discussed at the time. He is a witness.

         In your May 3rd message, you write

Actually, Cassen, Reynolds and Peale were the only ones to make any kind of detailed, coherent theory about an ocean on Europa,...

Wrong, Mr. Bara. Why have you not read my article An Ocean on Europa? and examined the papers discussed there? What about the paper Structural and Thermal Models of Icy Galilean Satellites by Consolmagno and Lewis? This was published in 1976 in the volume JUPITER: Studies of the interior, atmosphere, magnetosphere, and satellites. The paper is 16 pages and argues in favor of the theory that Ganymede, Callisto, and Europa all have oceans which have existed for billions of years and STILL EXIST, due to radioactive decay in the cores. The article is based on theoretical arguments and computer simulations, and includes predictions of the depth of the oceans.

         The preface of the volume in which this article appeared states that the intention is to present the "state-of-the-art" findings and theories concerning the Jupiter system. It is not an obscure publication in any sense of the word.

         There are earlier papers by Lewis too, and another later one by Consolmagno and Lewis. I cannot check this right now (since I am in Korea, and don't have access to an astronomy library), but I recall that one of the papers Lewis published in 1971 appeared in Icarus, a rather prestigious journal, and was about 12 pages. One of the main themes of those papers (four altogether, amounting to perhaps 40 or so pages) is the question of the existence of liquid water oceans on Ganymede, Callisto, and Europa, both in the past and the present.

         As I stated earlier, the 1976 paper of Consolmagno and Lewis clearly predicts that such oceans have existed for billions of years and still exist.

         The paper that Hoagland's discussion in The Europa Enigma is based on is a four-page article which appeared in Geophysical Research Letters in 1979. It contains a mathematical analysis of the possibility that the tidal forces of Jupiter could produce enough frictional heat in the crust to maintain a liquid water ocean below. It is a marvelous idea, which I believe was new at the time. (I have not found it elsewhere in the prior literature.) Unfortunately, their analysis in that paper was weakened considerably because of a mathematical error which was noticed later.

         However, those same authors did write a rather comprehensive paper in 1980, discussing the possibility of oceans on Europa, Ganymede, and Callisto, entitled Structure and Thermal Evolution of the Galilean Satellites. The paper also contains a rather thorough account of the earlier scientific literature on the topic. They do not completely rule out the possibility of oceans on Ganymede and Callisto. They state that the existence of oceans on those bodies might be possible if there is significant contamination in the water of dissolved salts or ammonia. They are more optimistic about Europa because of the role that tidal heating might play due to the eccentricity of the orbit.

         You write

"Previous models had supposed that an ocean ONCE MAY HAVE EXISTED -- but it was now frozen (Europa being too small to retain a significant radioactive heat source over billions of years ...)."

Again, this is wrong. Are you just making this up? The Consolmagno-Lewis theory did predict that oceans still exist on Callisto, Ganymede, AND Europa, as I have already mentioned. This is not just my version of history. It is what I have read in the literature. You can find the relevant quotes in my article An Ocean on Europa. However, as I report there, it is true that this was debated. Cassen and Reynolds challenged the idea in 1978, primarily for Callisto and Ganymede. But even for those moons, the 1980 article by those authors backs off a little on that challenge.

         The theory of Cassen, Peale, and Reynolds proposed in their 1979 paper Is there liquid water on Europa? was also challenged in the scientific literature. This is just normal scientific debate.

         Let me be more specific about things that should be changed on "europa.html."

Eliminate any hint or suggestion that Hoagland was ahead of the scientific community concerning the idea that Europa might have an ocean, or that it was in any sense his idea. This means that it must be made clear that this was an idea seriously considered by the scientists in 1979 and earlier.

Eliminate the cut-away illustration of Europa, or at least point out that this was the model suggested by scientists such as all the ones that I referred to above. Those models differ in predictions about the depth of the ocean, thickness of the crust, and the mechanism which maintains them. But none of those differences show up in the illustration.

         The question that I raised in my previous message still remains: Does Richard C. Hoagland want people to believe that he was the originator of the idea that an ocean exists on Europa? Or does he not?

         Mr. Bara, I have not ignored the fact that there are references to the work of Cassen, Peale, and Reynolds in The Europa Enigma. I did not mention it in my last message because it does not solve the problem. This is quite obvious because the myth about Hoagland's role concerning the idea of an ocean on Europa has flourished despite whatever Hoagland has written in his twenty-year old article. But I do discuss it in my essay The origin of this page on my website. I also mentioned it in the letter that I wrote in June, 1997 about Europa and Hoagland. I know that you have a copy of that letter. There I express the opinion that an attentive reader of Hoagland's article should realize that the idea of an ocean on Europa did not originate with Hoagland.

         That was my opinion at the time. I recall rereading those pages where he discusses that idea several times, trying to figure out how a reader who knew nothing about the history of the idea would interpret what is found there. I was not a typical reader since I did know something about the history.

         Readers of The Europa Enigma would certainly realize that it was Cassen, Peale, and Reynolds who predicted that Jupiter`s tidal forces on Io would cause extensive volcanic activity on that moon. That is stated clearly enough. But the fact that that it was those very same scientists who proposed that Jupiter's tidal forces might maintain an ocean on Europa is not quite so clearly stated. Mr. Bara, perhaps it would not be as easy as you think for readers to pick that fact up.

         Consider the case of Terence Dickinson. It's a pretty sad case to be sure. He was the editor of Star & Sky. He must have read Hoagland's article attentively. But it seems quite clear that he truly believed that it was Richard C. Hoagland who was the first to propose the possibility of an ocean on Europa. In the Toronto Star article that he wrote in 1997, he clearly and unambiguously attributes both the idea of such an ocean, AND the idea that tidal forces might be the reason that such an ocean exists, to Hoagland. Dickinson complains that Hoagland has not received due credit for his ideas about Europa. The ideas he is referring to include the specific ideas that he recalls hearing from Hoagland on two occasions.

         He quotes Hoagland as saying (at JPL):

"It's a crust of ice. And there's water below it."

And then Dickinson writes:

"Later, as he was working on the article, Hoagland phoned me from his home in Oakland, California, to tell me, with growing enthusiasm, about how all the pieces fit. Europa, he said, had a rocky core that was heated by gravitational tugging from Jupiter's three other large moons. As those moons swung close to Europa, then retreated, the varying gravitational forces squeezed and relaxed the rocky core, heating it in the process.

This, he said, would melt the icy crust that apparently cloaks the Jovian moon. Only the outer surface, which is exposed to the intense cold of space, remains frozen. The ocean below could easily contain more water than is in Earth's oceans. And like in Earth's oceans, he went on, life could exist near volcanic vents.

         Hoagland's ideas about Europa appeared as the cover story in the January, 1980, issue of 'Star & Sky'. Given the potential importance of the concept, I issued a news release to coincide with the issue's publication. It was picked up by all the major news services and the story ran in hundreds of newspapers. It appeared in 'The Toronto Star' on December. 27, 1979, under the headline 'By Jupiter! Maybe there is alien life in space'.

         Then, instead of Hoagland's ideas appearing in textbooks, NASA brochures and other publications about the solar system, they were ignored. Today, Hoagland almost never receives credit for his Europa work.

         Mr. Bara, Dickinson makes no distinction between what he heard Hoagland whisper at JPL and what Hoagland told him in the later phone conversation. Did Hoagland come up with both the idea of an ocean and the tidal heating theory by himself, or just one and not the other, or perhaps neither? Dickinson clearly believes the first. Why would Dickinson complain about Hoagland not receiving credit for those ideas if he knew that they had been proposed previously by other people?

         It seems far more likely to me that Hoagland came up with neither idea himself. But we will never know for certain - neither you nor me. Dickinson has no way of knowing either. Only Hoagland knows the truth about that.

         I do not believe that Dickinson was trying to mislead anyone in his Toronto Star article. I never had that opinion, and I am sorry if you misunderstood that. Perhaps I am jumping to a conclusion, but I believe that Hoagland was merely telling Dickinson what he himself had heard while hanging around NASA, and that none of it was original. Please note that I cannot say that he was intentionally trying to deceive Dickinson.

         So if Terence Dickinson failed to realize that it was Cassen, Peale, and Reynolds, and not Hoagland, who came up with the idea that tidal heating might preserve an ocean of liquid water on Europa, then how can you expect the average reader of The Europa Enigma to pick it up? Especially after reading the introductory page "europa.html."

         I will patiently wait for your revision of "europa.html."

---Ralph Greenberg