The Apollo Program – More Memories from Fifty Years Ago.

As most will know, it is fifty years ago since the first Moon landing. I was doing a post-doc in Australia at the time, and instead of doing any work that morning, when the word got around on that fateful day we all downed tools and headed to anyone with a TV set. The Parkes radio telescope had allowed what they received to be live-streamed to Australian TV stations. This was genuine reality TV. Leaving aside the set picture resolution, we were seeing what Houston was seeing, at exactly the same time. There was the Moon, in brilliant grey, and we could watch the terrain get better defined as the lander approached, then at some point it seemed as if the on-board computer crashed. (As computers go, it was primitive. A few years later I purchased a handheld calculator that would leave that computer for dead in processing power.) Anyway, Armstrong took control, and there was real tension amongst the viewers in that room because we all knew if anything else went wrong, those guys would be dead. There was no possible rescue. The ground got closer, Armstrong could not fix on a landing site, the fuel supply was getting lower, then, with little choice because of the fuel, the ground got closer faster, the velocity dropped, and to everyone’s relief the Eagle landed and stayed upright. Armstrong was clearly an excellent pilot with excellent nerves. Fortunately, the lander’s legs did not drop into a hole, and as far as we could tell, Armstrong chose a good site. Light relief somewhat later in the day to watch them bounce around on the lunar surface. (I think they were ordered to take a 4-hour rest. Why they hadn’t rested before trying to land I don’t know. I don’t know about you, but if I had just successfully landed on the Moon, and would be there for not very long, a four-hour rest would not seem desirable.)

In some ways that was one of America’s finest moments. The average person probably has no idea how much difficult engineering went into that, and how everything had to go right. This was followed up by six further successful landings, and the ill-fated Apollo 13, which nevertheless was a triumph in a different way in that despite a near-catastrophic situation, the astronauts returned to Earth.

According to the NASA website, the objectives of the Apollo program were:

  • Establishing the technology to meet other national interests in space.
  • Achieving preeminence in space for the United States.
  • Carrying out a program of scientific exploration of the Moon.
  • Developing human capability to work in the lunar environment.

The first two appear to have been met, but obviously there is an element of opinion there. It is debatable that the last one achieved much because there has been no effort to return to the Moon or to use it in any way, although that may well change now. Charles Duke turns 84 this year and he still claims the title of “youngest person to walk on the Moon”.

So how successful was the scientific program? In some ways, remarkably, yet in others there is a surprising reluctance to notice the significance of what was found. The astronauts brought back a large amount of lunar rocks, but there were some difficulties here in that until Apollo 17, the samples were collected by astronauts with no particular geological training. Apollo 17 changed that, but it was still one site, albeit with a remarkably varied geological variety. Of course, they did their best and selected for variety, but we do not know what was overlooked.

Perhaps the most fundamental discovery was that the isotopes from lunar rocks are essentially equivalent to earth rocks, and that means they came from the same place. To put this in context, the ratio of isotopes of oxygen, 16O/17O/18O varies in bodies seemingly according to distance from the star, although this cannot easily be represented as a function. The usual interpretation is that the Moon was formed when a small planet, maybe up to the size of Mars, called Theia crashed into Earth and sent a deluge of matter into space at a temperature well over ten thousand degrees Centigrade, and some of this eventually aggregated into the Moon. Mathematical modelling has some success at showing how this happened, but I for one am far from convinced. One of the big advantages of this scenario is that it shows why the Moon has no significant water, no atmosphere, and never had any, apart from some water and other volatiles frozen in deep craters at the South Pole that almost certainly arrived from comets and condensed there thanks to the cold. As an aside, you will often read that the lunar gravity is too weak to hold air. That is not exactly true; it cannot hold it indefinitely, but if it started with carbon dioxide proportional in mass, or even better in cross-sectional area, to what Earth has, it would still have an atmosphere.

One of the biggest disadvantages of this scenario is where did Theia come from? The models show that if the collision, which happened about 60 million years after the Earth formed, occurred from Theia having a velocity much above the escape velocity from Earth, the Moon cannot form. It gets the escape velocity from falling down the Earth’s gravitational field, but if it started far enough further out that would have permitted Theia to have lasted 60 million years, then its velocity would be increased by falling down the solar gravitational field, and that would be enhanced by the eccentricity of its trajectory (needed to collide). Then there is the question of why are the isotopes the same as on Earth when the models show that most of the Moon came from Theia. There has been one neat alternative: Theia accreted at the Earth-Sun fourth or fifth Lagrange point, which gives it indefinite stability as long as it is small. That Theia might have grown just too big to stay there explains why it took so long and starting at the same radial distance as Earth explains why the isotope ratios are the same.

So why did the missions stop? In part, the cost, but that is not a primary reason because most of the costs were already paid: the rockets had already been manufactured, the infrastructure was there and the astronauts had been trained. In my opinion, it was two-fold. First, the public no longer cared, and second, as far as science was concerned, all the easy stuff had been done. They had brought back rocks, and they had done some other experiments. There was nothing further to do that was original. This program had been a politically inspired race, the race was run, let’s find something more exciting. That eventually led to the shuttle program, which was supposed to be cheap but ended up being hideously expensive. There were also the deep space probes, and they were remarkably successful.

So overall? In my opinion, the Apollo program was an incredible technological program, bearing in mind from where it started. It established the US as firmly the leading scientific and engineering centre on Earth, at least at the time. Also, it got where it did because of a huge budget dedicated to one task. As for the science, more on that later.

Why do we do science?

What is the point of science? In practice, most scientists use their knowledge to try to make something, or solve some sort of problem, or at least help someone else do that. (Like most occupations, most junior ones turn up to work and work on what they are told to work on.) But, you might say, surely, deep down, they are seekers of the truth? Unfortunately, I rather fancy this is not the case. The problem was first noted by Thomas Kuhn, in his book, “The structure of scientific revolutions”. In Kuhn’s view, scientific results are almost always interpreted in terms of the current paradigm, i.e. while the data are reproduced properly, they are interpreted in terms of current thinking, even if that does not fit very well. No other theory gets a look-in. If a result does not conform to the standard theory, the researcher does not question the standard theory. The first effort is to find some way of accommodating it, and if that does not work, it may be listed as a question for further work, in other words the researcher tries to persuade someone else to find a way of fitting it to the standard paradigm rather than taking the effort to find an alternative theory.

According to Kuhn, most science is carried out as “normal science”, wherein researchers create puzzles that should be solved by the standard paradigm, in other words, experiments are set up not to try to find the truth, but rather to confirm what everyone believes to be true. This is not entirely unreasonable. If we stop and think for a moment, an awful lot of such research is carried out by PhD students, or post-doctoral fellows. The lead researcher has submitted his idea as a request for funding, and this is overseen by a panel. If you submit something that would not get anywhere within the current paradigm, you will not get funding because the panel will usually consider this to be a waste of time. On top of that, if you are going to include a PhD student in this work, that student needs a thesis at the end of his work, and that student will not thank the supervisor for coming up with something that does not produce results that can be written up. In other words, the projects are chosen such that the lead researcher has a very good idea as to what will be found, and it will be chosen so that it is unlikely to lead to too great an intellectual challenge. An example of a good project might to make a new chemical compound that might be a useful drug. The project might involve new synthetic work, there will be problems in choosing a route, but the project will not founder on some conceptual problem.

Natually, the standard paradigm clearly must have much going for it to get adopted in the first place. It cannot be just anything, and there will be a lot of truth in it, nevertheless as I mentioned in my first ebook, part 1 of “Elements of Theory”, any moderate subset of data frequently has at least two theories that would explain the data, and when the paradigm is chosen, the subset is moderate. If all that follows it to investigate very similar problems, then a mistake can last. The classic mistake was Claudius Ptolemy’s cosmological theory, which was the “truth” for over 1600 years, even though it was wrong and, as we now recognize, with no physical basis. If you wish to find the truth, you might follow Popper and try to design experiments that would falsify such a theory, but PhD theses cannot be based like that as it is too risky that the student will find nothing and fail to get his degree through no fault of his.

What brought these thoughts on was a recent article in the journal Icarus. The subject was questioning how the Moon was formed. The standard theory of planetary formation goes like this. After the star forms, the accretion disk that remains settles the dust on the central plane, and this gradually congeals into larger bodies, which further join together when they collide, and so on, until you get planetesimals (objects about the size of asteroids) then, apart from the asteroids, eventually embryos (objects about the size of Mars) which gravitationally interact and form very eccentric orbits, and then collide to form planets (except for Mars, which is a remaining embryo). All such collisions once planetesimals form are random, and the underpinning material could have come from a very large region, thus Earth was made from embryos formed from material beyond Mars and Venus. The Moon was formed from the splatter arising from a near glancing collision of a Mars-sized body called Theia with Earth.

If you carefully measure the isotope ratios of samples of meteorites, what you find is that all from the same origin have the same isotope ratios, but those from different parts of the solar system have different ratios. As an example, oxygen has three stable isotopes of atomic weights 16, 17 and 18. We have carbonaceous chondrites from the outer asteroid belt, a number of samples from Vesta, some from Mars, and of course unlimited supplies from here. The isotope ratios of these samples are all the same from one source, but different between sources. We also have a good number of samples from the Moon, thanks to the Apollo program. Now, the unusual fact is, the Moon is made of material that is essentially identical to our rocks, at least in terms of isotope ratios.

This Icarus paper carried out simulations of planetary formation employing the standard theory, and showed that since the Moon is largely Theia, the chances of the Moon and Earth having the same ratio of even oxygen isotopes is less than 5%. So, what conclusion do the authors draw? The obvious one is that the Moon did not form that way; a more subtle one is that planets did not form by the random collision of growing rocky bodies. However, they drew neither. Instead, they really refused to draw a conclusion.

I should add that I have in interest in this debate, as my mechanism outlined in Planetary Formation and Biogenesis has the planets grow from relatively narrow zones, although the disk material is always heading towards the star to provide new feed. The Moon grows at the same distance as Earth (at a Lagrange point) from the star and hence has the same composition. The concept that the Moon formed at either L4 or L5 was originally proposed by Belbruno and Gott in 2005 (Astron. J. 129: 1724–1745) and I regard it as almost dishonest not to have mentioned their work, which predicts their result provided the bodies form from local material. Unfortunately, the citing of scientific work that contradicts the standard theory is not exactly frequent, and in my view, does science no service. The real problem is, how common is this rejection of that which is currently uncomfortable?

You may say, who cares? It may very well be that how the Moon formed is totally irrelevant to modern society. My point is, society is becoming extremely dependent on science, and if science starts to become disinterested in seeking the truth, then eventually the mistakes may become very significant. Of course mistakes will be made. That happens in any human endeavor. But, do we want to restrict them to unavoidable accidents, or are we prepared to put up with avoidable errors?