Is science sometimes in danger of getting tunnel vision? Recently published ebook author, Ian Miller, looks at other possible theories arising from data that we think we understand. Can looking problems in a different light give scientists a different perspective?

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Archive for April, 2014
Only two papers qualified for inclusion in two months, so perhaps I should remind readers that the criterion for qualification is that the paper was relevant to my theory of planetary formation, which differs from the standard one in that the reason matter accretes is because of some chemical feature, including physical chemistry, whereas standard theory just assumes planetesimals accrete by some unknown mechanism. The consequences of my approach is that because what happens with chemistry is highly temperature dependent, the various bodies of the solar system should fall into different groups (centred around a planet) with properties of the group if they are small enough. (Gas giants simply collect everything, but their moons qualify.)
 
So with that in mind, there were two announcements that I found surprisingly satisfying. The first was the announcement of the discovery of a "clump" of carbon monoxide gas of about 0.09% the mass of the moon in the debris disk of Beta Pictoris. (Dent et al, Science 343: 1490 – 1492) This gas clump was argued to be a region of enhanced collisions of many objects, the collisions there being a result of mean motion resonance with an unseen giant planet that is greater than 10 earth masses, or from the remnants of a collision of Mars-mass planets. There is tentative evidence to favour the first interpretation. The authors suggested a giant planet at 60 A.U would provide a 2:1 resonance.
 
Why do I find that of interest? Well, based on dust distributions and my theory, I considered the planets to be as follows: Uranus equivalent at 68 A.U., Neptune equivalent at 114 A.U., with resonances at 82 A.U. 3:4 with the Uranus equivalent and 3:2 resonance with the Neptune equivalent. The bodies causing the collisions should have originated from around Neptune or from the equivalent of a Kuiper Belt, assuming similar dynamics to our system. Now, the reason I find this important is because only objects from this distance are cold enough to accrete carbon monoxide in the ices that make up the core. (Jupiter has carbon monoxide, but Jupiter accreted most of its gas gravitationally from the disk, and thus accreted all available gas.) My argument is that it is the presence of the carbon monoxide (and nitrogen) that enabled objects that would cause Neptune and Kuiper belt objects to accrete. As an aside, this explains why Neptune is bigger and denser than Uranus: carbon monoxide and nitrogen were far more prevalent than methane and argon, the gases that started Uranian accretion. Accordingly Neptune will accrete more solids, although once it gets big enough, Uranus will accrete gases faster because of the higher gas density. However, back to the issue. The gravitational field of the Neptune equivalent will stir up objects reasonably close to Neptune, and lead to such collisions. There should be other planets there (and one is known somewhat closer to the star) but there is no corresponding "clump" of carbon monoxide. That does not prove anything, but at least it is in accord with what my theory would predict.
 
The second announcement was that a second Sedna-like object, 2012VP113 with a perihelion distance of 80 A.U. has been found (Trujillo and Sheppard, Nature 507: 471 – 474). Such objects are sufficiently far away that they do not interact gravitationally with any other known planet. One interesting feature of these is that each has a relatively high eccentricity (VP  0.7, Sedna 0.86), and such eccentricities would usually be interpreted as arising from an acute gravitational interaction with something else, There appear to be no objects between 50 and 75 A.U., at least of any size, which raises the question, how do such bodies form. One possibility raised was gravitational interactions with a super earth, possibly as far away as 250 A.U.
 
How does that affect my theory of giant planet formation? That is difficult to say. The theory assumes that the ice planet cores accrete by ices sticking together when they strike each other due to an icy constituent melting and refreezing. (Vapour pressure is not relevant because the gases are occluded in water ice channels. Such ices have been made and are stable at very low pressures.) If so, my theory allows for another ice planet, or at least icy bodies, provided neon is the brazing component. The problem then is, where would the planet be? The variables are, the temperature below the melting point where collisions are effective, the heating function of the accretion disk, the orbital velocities, and the initial temperature. By simple extrapolation of the temperature relationship used for the other giant planets, the answer is 95 A.U., but the problem then is that this assumes that the initial gas temperature was zero. If something is proportional to A – B , if B is only at worst a few per cent of A, then given all the other uncertainties, errors in B can be ignored, but if B is approaching A, it is really serious. When we get down to neon, such failures in the approximations will make a big difference. There is a test: the bodies such as Sedna should contain neon below the surface, if I am correct, but how to find out?
Posted by Ian Miller on Apr 13, 2014 11:36 PM BST
I started this off by asking how the ancients could prove the Earth goes round the Sun, so I had better come up with an answer. (Rather interestingly, no reader has. Perhaps I have no readers!)
 
My answer actually follows in part one of the arguments that Galileo used, although he did not quite get it right. First, it has to be possible, so it is necessary to demonstrate the Equivalence Principle, namely that all things fall at the same rate. However, before doing that, you have to get rid of Aristotle's constrained motion. In my novel Athene's Prophecy, I had my Roman protagonist project a small arrow through water and through air, thus demonstrating the presence of frictional dissipative forces. Once you have got that far, you can drop different weights, but ones that are not going to suffer unduly from air friction. Once you accept that all things fall at the same rate in a constant field, then orbital motion becomes possible, even if you do not know the field is inverse square in nature. However, there is a difference between "possible" and "is".
 
In my view, you can do it with tides. In the second book of this trilogy, shortly to be available, my Roman goes to France for the invasion of Britain and sees the big tides in France. The correlation with the position of the Moon is sufficient to realize that the Moon is the cause, but how? Even now, most people would argue the Moon pulls the water towards it, but this is only partially correct. It is obvious there are no tides in lakes, and indeed if you attribute a gravitational force to the Moon, it is nowhere nearly as strong as Earth's at the surface. Further, if everything is falling at the same rate, then the water should be falling at the same rate as the rock, and everything should stay in the same place. So, what is wrong with that argument?
 
When devising a theory, when you run into something like that, the first thing to do is not to abandon your thoughts but rather ask, what is being missed? In this particular case, two things should strike you. First, there are two tides a day. If tides were simply due to attraction, there should be only one, because a single force cannot push and pull both at the same time. The second thing that should occur to you is that just maybe the size of the planet should be included. Now the cause of the tides becomes obvious. The orbital velocity of the planet determines the velocity at the centre of the planet, and as the body get further from the centre, the force is weaker, and consequently the orbital velocity at that point is slower. The tides arise because the changes due to the size of the earth do not correspond to what is required by the orbits at those points. Note that to make that work, the ancients would have to conclude that the force towards the centre attenuates with distance. It does not need the inverse square relationship, but it does require attenuation.
 
Thus the point nearest the Moon is moving too slowly for its distance while the moon's force is stronger, and there is an accelerating component towards the Moon. Of course, the force towards the centre of the earth is still much stronger, so there is no net motion. However, there are points not directly below. Now there is a vertical and a horizontal component, and while the vertical component is overwhelmed by the Earth's gravity, there is no opposing force to the horizontal component, and the water flows sideways to form a wave crest that follows the Moon. The second tide arises because the point farthest from the Moon is moving too fast for the attenuated force there, and the water sustains an accelerating force away from the centre, and this too has components when the water is not on the moon-earth line. The two tides prove the Earth must be moving. If it is moving, and the Sun stays the same size, it must be moving in a circle around the Sun, and by the same argument, there will be a further pair of waves due to the sun tide. That proves the heliocentric theory, with reservations.
 
You now face a problem: you appear to have shown that the Earth goes around the Moon, and not vice versa. In such a case, it is helpful to create a fictitious situation and test the limits. Thus you could ask, what would happen if the Earth and the Moon were the same mass? Which goes around which? The answer is obviously that since each receives equivalent forces, each behaves exactly the same way, and hence each moves around a common "centre of mass". (The ancients may not have put it like that, but they could make that qualitative argument.)
 
The next point in devising a theory is, when you get something you feel should be correct, you should use it to make a prediction. The prediction would ideally predict something that you did not know, but because there are so many observations it may be necessary to simply unify some points that are known. In this case, you should argue that if the Moon causes two tides, so should the Sun, but because it is further away, its effects are weaker. You therefore predict two waves, each with two crests that travel around the Earth, one in phase with the Moon, the other with the Sun. A little bit of geometry and the knowledge of how a wave behaves and you can start to predict relative tidal heights at different times during a lunar period. When you start doing that sort of thing, you begin to know that you understand something.
 
The purpose of the above has been to show one way how theories can be formed, but I have also hoped to show something of classical science, and how difficult it is to understand something for the first time. It is also interesting to consider how science is taught at schools. I wonder how many pupils are merely told that the tides arise because the moon pulls on the water?
Posted by Ian Miller on Apr 2, 2014 3:34 AM BST