Surprisingly successful (or failed) predictions? Options

[elakdawalla]

In response to my recent plea for questions for Planetary Radio, I got this one, mentioning an event I hadn't been aware of.

Back in 1979, literally a week or so before Voyager I encountered Jupiter, a planetary scientist published a paper (in Science, I believe) postulating that tidal forces created by Jupiter's gravitational pull would trigger volcanic eruptions. It was a remarkably prescient article. There must be other examples of successful predictions of conditions on other planets or their moons. It would be fascinating to learn about them.

Here's the Science article he refers to.

Does anybody else know some other examples of spectacularly successful predictions that were actually published by researchers? (Lots of people speculate, but I think it's probably rarer to get this stuff past peer review.) And, for fairness, what about spectacularly unsuccessful predictions?

--Emily

[JRehling]

On the errant-prediction end, the first thing that comes to my mind are the many models of planetary system accretion, which I always thought were quite cool (the TV series Cosmos showed some sample output) that never predicted hot Jupiters.

But there are so many examples, we could focus just on the most flagrant. Just consider what was said about Venus before anyone peeked beneath the clouds. Jungle? Oceans?

Famously, Thomas Gold predicted that a lunar lander might sink into powdery dust, never to be seen again. Boy, was Mrs. Armstrong glad he was wrong.

Pre-spaceflight, many including Patrick Moore predicted that the Moon's craters would prove to be volcanic in origin.

An epic success would be the prediction of Neptune's existence. It depends on how impressed you want to be. Given enough evidence, nothing is surprising. Was the case for Neptune on the basis of perturbation so solid that predicting its existence was actually unimpressive?

The return of Halley's Comet is a similar case. Halley saw the pattern in the data, and I'm sure there was plenty of noise (after all, it isn't the only comet). It was a bold and falsifiable prediction that proved to be valid.

I think Ralph Lorenz among others described certain aspects of Titan pretty accurately when all we had were poor IR global maps and lots of indirect measurements.

[Mariner9]

I thought everyone knew about the Io volcanoes being predicted, and that prediction being published, before the Voyager 1 flyby.

But then I suppose that just goes to show two things. One, people tend to assume that the things they know are common knowledge. Two, that I'm getting older than some people, and was already an adult with an avid interest in these things at the time that Voyager was launched. I was reading everything I could get my hands on in those days (and still am), and the Io story was a antecdote that people loved to tell.

Another one that I think is common knowledge, but may not be, is that Carl Sagan correctly predicted that the seasonal changes in albedo on Mars was due to the dust storms moving dust around on the Martian surface. I'm not clear if he thought the dust was light or dark, if he thought the dust was dark then he had the prediction somewhat backwards (I think that the reddish dust gets blown off the underlying rock and bedrock, exposing a darker grayish surface).

I think he also predicted that the Venus surface would turn out to be very hot, precluding the ideas of oceans and jungles.

In both cases I beleive he (and possibly collaborators) published these predictions.

I'm not so old that I remember the Mars and Venus results being published. I may have been alive at the time, but was still watching saturday morning cartoons and learning to ride a bicycle.

[Mariner9]

On the "boy were we wrong" side of things, much more recently there is the case of asteroid regolith. I think that before we got to Eros it was commonly thought that for the most part asteroids as small as Eros could not hold onto soil and boulders after impacts... because the gravity was so low that the debris would all be flung out at higher than escape velocity. Turned out that NEAR found lots of debris and soils.

Even after that, it was felt that REALLY small asteroids, like say Itakowa, could not hold onto small rubble, so it would be just one large fragrment left over from some earlier larger asteroid breakup.

Oops. Turns out Itakowa was a classic flying rubble pile with boulders ranging in size from 50 odd meters, down to small pebbles. So much for thinking that the Hayabusa mission was heading towards an unremarkable target.

[Littlebit]

Hannes Alfven's predictions of both the solar and galactic Electromagnetic fields - big surprises

From His Nobel Prize Biography:
http://www.alfvenlab.kth.se/hannes.html

His work on the cosmic-ray problem led him to propose in 1937 the existence of a galactic magnetic field. Because interstellar space was, then, held to be a vacuum, it was widely believed that there could be no interstellar magnetic field because the magnetic field of individual stars, declining in a vacuum as 1/r3, would be too weak to fill interstellar space. Alfvén proposed that interstellar space could contain sufficient plasma to carry electric currents that would produce the required field locally. Only much later was the existence of the galactic magnetic field confirmed, and, as is typical of many of his contributions, without formal recognition of his original proposal.

It is also worth mentioning that I don't know of anyone who successfully predicted what would happen when Deep Impact ploughed into Tempel 1.

Another surprise; the rocky strata Haybusa wondered into on 'It is quick'.

The twisted rings of Saturn were a big surprise...does anyone know if anyone predicted this?

[stevesliva]

I think he also predicted that the Venus surface would turn out to be very hot, precluding the ideas of oceans and jungles.

That raises the question of whether reasonable conclusions from analysis of radiotelescope observations are "predictions." Like the Van Allen Belts were discovered... not predicted, at least by Van Allen.

I think we're looking here for predictions that are not the direct inference of observation. Like the Kuiper Belt or the Oort cloud. And of course there are the predictions that aren't exactly controversial, like "There will be Neptunian Trojan Asteroids." But then again, there are the failed predictions based on observation like Vulcan, Nemesis, and Planet X.

[ngunn]

I believe that in 1955 the then British Astronomer Royal went on record as saying that space travel was "utter bilge". Two years later . . . .
Maybe someone can confirm the details.

Oh yes, and Fred Hoyle predicted that the Big Bang theory (his coining) was doomed to fail. Successful or unsuccessful? I don't know, but spectacular either way!

[helvick]

Jonathan Swift's prediction in "Voyage to Laputa" (1726) that Mars had two close in moons was definitely a prediction not based on any actual data.

[JTN]

Jonathan Swift's prediction in "Voyage to Laputa" (1726) that Mars had two close in moons was definitely a prediction not based on any actual data.

Did that pass peer review then?

[Tom Tamlyn]

I remember reading that there had been a prediction in (I think) Astronomy Magazine to the effect that Comet Shoemaker-Levy 9 would slip into the atmosphere of Jupiter without any noticeable commotion.

I believe I read this in "Shoemaker by Levy."

TTT

[Elias]

The physical justification for the existence of a solar wind + the solar wind spiral by Eugene Parker. Rejected twice by peer review journals (solar wind):

Eugene Parker realised that the heat flowing from the Sun in Chapman's model and the comet tail blowing away from the Sun in Biermann's hypothesis had to be the result of the same phenomenon, which he termed the "solar wind".[4][5] Parker showed that even though the Sun's corona is strongly attracted by solar gravity, it is such a good conductor of heat that it is still very hot at large distances. Since gravity weakens as distance from the Sun increases, the outer coronal atmosphere escapes supersonically into interstellar space. Furthermore, Parker was the first person to notice that the weakening effect of the gravity has the same effect on hydrodynamic flow as a de Laval nozzle: it incites a transition from subsonic to supersonic flow[6]

Opposition to Parker's hypothesis on the solar wind was strong. The paper he submitted to the Astrophysical Journal in 1958 was rejected by two reviewers. It was saved by the editor Subrahmanyan Chandrasekhar (who later received the 1983 Nobel Prize in physics).

In January 1959, the first ever direct observations and measurements of strength of the solar wind were made by the Soviet satellite Luna 1. However, the acceleration of the fast wind is still not understood and cannot be fully explained by Parker's theory. Shortly thereafter, an unambiguous solar wind measurement was performed by Neugebauer and collaborators using the Mariner 2 spacecraft [7].

[Bjorn Jonsson]

Jupiter's ring was predicted from Pioneer particles and fields data back in 1976 if memory serves. I don't remember where I read this, possibly in the Voyager 1 special issue of Science (which I do not have at the moment).

Spectacularly incorrect Venus predictions: Oily oceans and jungles.

Incorrect Jupiter predictions: That Io would be the Rosetta stone for deciphering surface ages in the Jovian system due to its rocky composition and as a consequence heavily cratered surface. That the surfaces of Ganymede and Callisto would look very smooth and without craters because these two satellites are composed largely of water ice.

[jsheff]

The existence of craters on Mars seemed to come as a total surprise during the Mariner 4 flyby of the planet in 1965, and led to the view that Mars was more Moon-like than Earth-like. But there were some skilled observers using large observatory telescopes that claimed in the 1940's and 1950's to be able to see craters on Mars, among them E.E. Barnard, R.B. Baldwin, C.L. Tombaugh, and E.J. Opik. If my memory serves me well, Steven James O'Meara, whose eyesight is lengendary, claims to be able to see them now; I wouldn't doubt it.

John Sheff
Cambridge, MA

[tasp]

JPL folks were cautioned to be on the look out for moons with moons, and moons with rings during the ramp up to the Voyager flybys.

{I think I saw this on the Nova episode 'Resolution on Saturn', but I might be wrong}


If someday it turns out the Trojanettes (and maybe Hyperion, too) are tidally divested sub satellites, and that the Iapetan equatorial ridge is an orbitally decayed ring system, I would be thinking that was some pretty awesome advice for 1980/1.

[dvandorn]

Well, hmm -- not only a prediction, but "established fact" well into the 20th century was that space was actually filled with "aether," a gaseous medium that filled the void between the planets and stars.

Also, in the arena of lunar predictions, there are all of the crazy predictions by Spurr and Green, including the idea that the lunar seas were dried-up ocean beds. (As Don Wilhelms put it, the Moon is neither Spurrish or Greenish... .) And, more subtle but just as wrong, there were the predictions by the photogeology team that the Descartes and Cayley formations represented highland volcanics.

-the other Doug