Bluffing About Earth's Magnetic Field and Life's Chirality
The headlines might make one think evolutionists have finally scaled two monstrous hurdles for their theory.
Earth’s Magnetic Field
Evolutionary geologists have two big problems with Earth’s magnetic field: (1) explaining its origin and (2) explaining its longevity. We saw Nature reporting last January (1/25/16) about an energy crisis in leading theories of how a geodynamo started in Earth’s core. The best theories as of 2012 could not keep the dynamo running for more than 1/5 the assumed age of the Earth. Now, Nature reports new “Direct measurement of thermal conductivity in solid iron at planetary core conditions.” An international team succeeded in characterizing the behavior of iron at the high temperatures and pressures assumed to exist in the core. “Attempts to describe thermal transport in Earth’s core have been problematic, with predictions of high thermal conductivity at odds with traditional geophysical models and direct evidence for a primordial magnetic field in the rock record,” they say. “…. The result is in agreement with palaeomagnetic measurements indicating that Earth’s geodynamo has persisted since the beginning of Earth’s history, and allows for a solid inner core as old as the dynamo.” Science Daily portrayed this experimental result from a lab as evidence that the “energy necessary to sustain the geodynamo has been available since very early in the history of Earth.”
In the same issue of Nature, a Japanese team reports “Experimental determination of the electrical resistivity of iron at Earth’s core conditions.” Their results are not encouraging for believers in billions of years. If the core has low electrical resistivity, electrons can move faster and dissipate heat quicker. “The low electrical resistivity of iron indicates the high thermal conductivity of Earth’s core, suggesting rapid core cooling and a young inner core less than 0.7 billion years old,” they say. “Therefore, an abrupt increase in palaeomagnetic field intensity around 1.3 billion years ago may not be related to the birth of the inner core.”
Putting these two findings together, David Dobson writes for Nature that the findings seem contradictory. He sets up the core competency problem:
In 2012, first-principles numerical simulations indicated that the thermal conductivity of liquid iron in the outer core is so high that this region might act as a pump that pushes heat towards the core–mantle boundary faster than convection can. If, as these controversial studies suggest, the core is losing heat at such a high rate, it means that the magnetic field must work in previously unimagined ways, and that the solid inner core must be less than a billion years old — a mere babe in planetary terms. In this issue, Ohta et al. (page 95) and Konôpková et al. (page 99) report studies that experimentally tested the simulations’ results using complementary, but distinct, approaches and come to different conclusions.
How can geophysicists reconcile the high thermal conductivity with the low electrical resistivity? Dobson can only surmise that one or both teams used wrong assumptions, made experimental errors, or drew wrong conclusions. But neither team can keep the field going for the full assumed age of the Earth (4.5 billion years).
The discrepancy makes a big difference to estimates of when the inner core formed, and hence when Earth generated a stable magnetic field — the inner core could be as little as 700 million years old, about the same age as complex life; or as much as 3 billion years old, about three-quarters of Earth’s age.
Three billion years is only two-thirds the assumed age of the Earth. What changed after the first one-third? And what about other planets and moons that have magnetic fields, with and without iron cores?
Cooper and Rios announce with gusto in PNAS that meteorites have been found with a substantial excess of right-handed sugar molecules over the left-handed forms. This “enantiomeric excess” holds true for both rare and common sugars, they claim. “Such data indicate that early meteoritic compounds may have influenced the enantiomer profile of subsequent biological sugars and their derivatives.” Since life uses only the right-handed (dextro or D-) form, evolutionists have long wondered how that arose.
Inside the paper, though, the alleged excesses are only around 55%. One outlier, xylonic acid, has a claimed excess of 82%, but this 5C sugar is a metabolite of vitamin C that is excreted in the urine. Generally, the more carbons (4C to 6C), the more the excess, but there are exceptions. The authors do not provide any firm mechanism that would produce the slight excesses; in life, the sugars in DNA and RNA are 100% right-handed. The researchers mention old standbys that might be involved—circularly polarized light and magnetic fields from stars—but those are reversible mechanisms. They conclude with mere suggestions of possible roles in life. As usual, more research is needed.
Asymmetric meteoritic compounds may have either played a direct role in the formation of the first homochiral biological polymers or influenced the chirality of their subsequent syntheses. It now seems possible that the EE of two meteoritic classes of compounds, sugar acids (D) and amino acids (L), qualitatively match the excesses of the corresponding classes in extant biology. However, although we have used criteria (rare compounds/enantiomer and isotope ratios) in attempts to discern extraterrestrial from Earth material in the present samples, it is critical that current and future space missions capable of enantiomer analysis examine and/or return samples of carbonaceous material to verify laboratory enantiomer measurements of meteoritic compounds.
They did not address the dilution problem (the quantity of homochiral material required to be delivered), the racemization problem (keeping the excesses from reverting to 50:50 mixtures), or the probability problem (calculating the chance of getting only homochiral sugars to link up).
These papers are important for showing that the very best that secular scientists can find does not solve their problems. These problems have existed for well over a century.
For philosophers of science, one should question whether carefully-designed experiments in a lab dealing with tiny samples can speak to a planet’s core many hundreds of miles in diameter, where variations in temperature and composition are likely. One should also ask what relevance scattered fragments of delicate sugars could have over vast oceans. And even if there was a “substantial” enantiomeric excess in some meteorites, could not the excesses go the other way in other samples, averaging out to racemic? What would maintain the excess once the meteorites land? What would prevent their racemizing in any hypothetical primordial soup?
Researchers should be more reserved about the relevance of their findings to these major questions. To say the results “may have… played a role” in the origin of life or of the Earth’s magnetic field is very misleading. State the facts and let the reader decide.