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?

October Planetary Update

Again, my theories on planetary formation survive another month, although if I were rewriting I would amend the literature survey a little. There were three papers of particular significance. 
 
Paniello (Nature, 490: 376) examined zinc isotope evidence from lunar rocks and concluded that the moon had an additional condensation step than Terran rocks. This is in accord with the generally accepted theory that the Moon was formed by the condensate from a collision of a body called Theia with Earth. By itself, this is unexceptional, however there was also a comment by Elliot (Nature, 490: 346) in which he notes that collisional models suggest the Moon should be made predominantly from material originating from Theia, in which case isotope distributions of non-volatile elements should match Theia, but they are essentially identical to those of Earth. Elliot suggests that this requires an extremely rapidly rotating Earth prior to collision, which seems unlikely. Elliot overlooked the option that Theia accreted at an Earth-sun Lagrange point (Belbruno and Gott. 2005. Astron. J. 129: 1724) either L4 or L5, in which case Theia would have the same isotopes. I favour that interpretation, mainly because my theory argues that Earth forms at the most favourable temperature for rocky accretion.
 
Shcheka and Keppler (Nature 490: 531) did me a favour. One big problem in accounting for earth's atmosphere is why is xenon depleted compared with argon, and to a lesser extent, krypton. One answer is that the initial atmosphere suffered strong hydrodynamic escape to space, which led to an enhancement of heavy xenon isotopes, but that should remove almost all the argon. These authors found that perovskite, which makes up much of the Earth's mantle, can dissolve up to 1% argon. The reason is, anomalies in perovskite (MgSiO3) arise through elements like aluminium getting in, which create holes that are roughly the same size as argon. Xenon, being bigger, does not fit. Under this scenario, the early hydrodynamic escape (powered by intense solar radiation on an atmosphere of retained accretion disk gases) of hydrogen and helium drags off most of the other elements, and subsequent argon is released, without heavy isotope enhancement, by volcanic degassing.
 
Cassata et al. (Icarus 221: 461) determined isotope ratios of trapped argon from the Martian meteorite ALH84001 and concluded that the atmospheric pressure on Mars at 4.16 Gy BP was < 400 mbar, and accordingly a CO2 atmosphere could not have had sufficient pressure to have sufficient greenhouse gas to permit water to flow. This strongly supports my theory, in which it was ammonia that dissolved in water and lowered the melting point. At first I got excited, because these authors used a C/N ratio that only made sense if the nitrogen ended up underground. That would strongly support my theory, but unfortunately it did not. Closer reading showed they assumed the C/N ratio.
 
Finally, you may wonder why I got involved with planetary formation theory. In the early 1990s, thanks to a persistent economic downturn, I had some spare time, so I wrote a science-fiction book about the colonization of Mars, in which the bad people were intending to get rich by floating junk shares/stock on Earth. (There were plenty of examples of fraud to learn from in the previous decade!) To expose the fraud, I needed an unexpected discovery, and in my background, I had published one paper arising from the idea that the CO2 atmosphere beloved of geologists would lead to basalt weathering and giving ferrous ions, which, in turn, could photochemically reduce CO2. We did some experiments and it does, but then I became concerned; what happened to the ferric ions? A few experiments showed that ferric ions are very aggressive at photochemically attacking carbohydrates and amino acids. Somehow, CO2 being part of the origin of life became much less attractive.
 
Accordingly, for my required "unexpected discovery", I tried for a reduced atmosphere, which would lead to massive underground deposits of urea. (Yes, I know it might go further, but . . .) My agent managed to persuade the editor of a major publisher to look at it, but the editor died. The replacement cleared the desk, and rejected my novel on the grounds it was too implausible. I was fairly confident "colonization of Mars" was not too bad for SciFi, with big money around, fraud is hardly implausible, so that left the reduced atmosphere. How dare a literary editor trash my chemistry! So I became involved. The experts say that thanks to UV radiation, ammonia would only last decades and so is irrelevant, nevertheless the only available sample of ocean from about 3.2 Gy BP has levels of ammonia in it approaching those of potassium. I back observations over "experts", even if the observers did not realize the significance of what they found. Incidentally, if anyone is interested, the offending book, Red Gold is now available as an ebook on Amazon, and I have included a précis of the theory in an appendix.
Posted by Ian Miller on Oct 27, 2012 12:24 AM Europe/London

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