Young Earth Research Articles

Transport properties of Mg 2SiO 4 liquid at high pressure: Physical state of a magma ocean

We use a flexible potential model to perform large-scale molecular dynamics simulations on self-diffusivity and viscosity of Mg 2SiO 4 melt up to pressures of 32 GPa and over a temperature range of 2600 to 3200 K. We find that self-diffusivity decreases and viscosity increases uniformly with pressure, the latter from values of 10 − 2 Pa s at 0 GPa to 10 − 1 Pa s at 32 GPa (2600 K). Both transport properties can be readily fit with a closed Arrhenius expression over the whole pressure and temperature range considered. Independent estimates of self-diffusivities and viscosity allow us to examine their relation through the Stokes–Einstein and the Eyring equations. While at low pressures the SiO 4 tetrahedron seems to be the viscous flow unit, bare ion diffusion becomes more dominant at high pressure. Combining previous simulation results on thermodynamic properties with the current viscosity simulations we compute a magma ocean adiabat and the associated viscosity profile. We find that viscosity in the magma ocean is ∼ 2 · 10 − 2 Pa s near the surface, and that it increases by less than 0.5 log-unit up to 35 GPa. Combining scenarios for magma ocean dimensions in the young Earth with thermodynamic properties and viscosity of Mg 2SiO 4 melt we compute a magma ocean Rayleigh number Ra in the range of 10 28 and 10 29, putting the magma ocean in the dynamic regime of hard turbulence. Using scaling relations for the Nusselt number Nu at very high Ra we estimate the heat flux of the magma ocean to be in the range of 10 18 to 10 19 W.

The Potential for Low-Temperature Abiotic Hydrogen Generation and a Hydrogen-Driven Deep Biosphere

The release and oxidation of ferrous iron during aqueous alteration of the mineral olivine is known to reduce aqueous solutions to such extent that molecular hydrogen, H2, forms. H2 is an efficient energy carrier and is considered basal to the deep subsurface biosphere. Knowledge of the potential for H2 generation is therefore vital to understanding the deep biosphere on Earth and on extraterrestrial bodies. Here, we provide a review of factors that may reduce the potential for H2 generation with a focus on systems in the core temperature region for thermophilic to hyperthermophilic microbial life. We show that aqueous sulfate may inhibit the formation of H2, whereas redox-sensitive compounds of carbon and nitrogen are unlikely to have significant effect at low temperatures. In addition, we suggest that the rate of H2 generation is proportional to the dissolution rate of olivine and, hence, limited by factors such as reactive surface areas and the access of water to fresh surfaces. We furthermore suggest that the availability of water and pore/fracture space are the most important factors that limit the generation of H2. Our study implies that, because of large heat flows, abundant olivine-bearing rocks, large thermodynamic gradients, and reduced atmospheres, young Earth and Mars probably offered abundant systems where microbial life could possibly have emerged.

Threshold effects in assembling a cell on a young planet

Molecules in the young Earth's oceans underwent a finite number C of collisions during the time interval which elapsed between Earth's formation and the emergence of life. The finiteness of C sets an upper limit G on the number of constituent molecules which could have been randomly assembled into a genetic molecule from a reservoir of the relevant constituent molecules for use in the first cell. A viable cell requires a certain minimum number of genes in order to be functional: this means that the genetic material must include a minimum number M of the constituent molecules which encode for information. The question we address here is: is it mathematically possible for G to take on values which are at least as large as M? The answer is Yes, provided that we allow for the fact that there is a large amount of flexibility (non-specificity) in the operation of biological molecules. When this flexibility is allowed for, we find that G can be comparable to M provided that the mass of constituent molecules which were available in the pre-biotic Earth exceeded a certain threshold. Our estimates indicate that a mass on the order of a few tons would satisfy the threshold.

Protestant Responses to Darwinism in Denmark, 1859–1914

From the 1870s onwards, Charles Darwin's theory of evolution, published in On the Origin of Species (1859) and Descent of Man (1871), was an important topic among the followers of the influential theologian N.F.S. Grundtvig (1783-1872). The Grundtvigians constituted a major faction within the Evangelical-Lutheran Established Church, which included more than ninety percent of the population in the period 18591914.This article demonstrates the influence of local contexts on the reception of scientific ideas by analyzing how specific aspects of intellectual culture made the Grundtvigian reactions to Darwin's theory different from Protestant denominations in America and Britain. Firstly, Grundtvig's critique of Lutheran scriptural theology and his preference for the living word to the letters of the Bible legitimized liberal interpretations of Scripture. Secondly the philosophy of the Soren Kierkegaard protagonist, Rasmus Nielsen, made it possible for Grundtvigians to draw radical distinctions between science and faith. This specific Danish Protestantism, as the clergyman Frederik Jungersen phrased it in 1873, led the way for liberal Grundtvigians in coming to terms with Darwinism in the first decades of the twentieth century.1PROTESTANT RESPONSES TO EVOLUTIONIn recent decades historians have paid considerable attention to religious responses to Darwinism. Studies have revealed a variety of reactions to evolution depending on local contingencies, which has made it impossible to uphold any grand narrative of the dissemination of Darwinism.2 In his study of Calvinist attitudes toward Darwinism in Princeton, Belfast, and Edinburgh, David N. Livingstone thus emphasizes the importance of place in the reception of evolution.3 The historical complexities shaped by local contexts have been further demonstrated by scholars, who have explored the responses to Darwinism in a wide range of Protestant denominations in Britain and America.4 From the 1870s, when evolution was generally accepted among British and American scientists, liberal and even some orthodox theologians advocated various kinds of theistic evolutionism. It was not until the 1920s that creationists, who rejected evolution in general and human evolution in particular, took center stage in American Protestant answers to the Darwinian challenge. While many Protestant theologians in the decades around 1900 accepted that God had created the living world, including man, through evolution, very few embraced the specific Darwinian mechanism of natural selection that was often said to have atheistic implications. Instead liberal theologians, in line with many naturalists, often applied Lamarckian concepts of use-inheritance and teleological development and prevalent ideas of progress that were seen as consistent with viewing evolution as a meaningful process and the unfolding of the Creator's plan. According to James R. Moore, Peter J. Bowler, and Frederick Gregory this was the common way for liberal Christians to respond to organic evolution at least in the English-speaking world. It offered an acceptable compromise between science and faith. However, this article demonstrates that this strategy did not dominate in Denmark, where a separation model of science and faith was a more widespread approach when embracing the theory of evolution.5While studies by Jon H. Roberts and Ronald L. Numbers reveal considerable differences within the leading Protestant denominations such as Calvinists, Baptists, Lutherans, Episcopalians, and Methodists in their attitudes toward evolution, they detect no significant differences among the groups. Numbers notes however that theological convictions sometimes influenced how people viewed Darwin's theory.6 This was especially the case when we move from the Protestant mainstream into distinctive groups such as the Seventh-day Adventists and the Pentecostals. In the case of the Adventists, their hyper-literalism and strong support for youngearth creationism owed much to the inspired writings of their founding prophetess Ellen G. …

A full-sphere convection-driven dynamo: Implications for the ancient geomagnetic field

The solid inner core of the Earth formed at 2–3 Ga as a result of the gradual cooling of the Earth’s deep interior plays an essential role both energetically and dynamically, in the generation of the Earth’s present magnetic field. In the early stage of the Earth’s evolution, however, the entire core was made of molten liquid. Understanding convection-driven dynamo in a full sphere is hence of importance in elucidating the dynamics of the young Earth and its ancient magnetic field. We present a numerical convection and dynamo model for the full sphere using a finite element method. A large effort is made to efficiently parallelize the dynamo model so that it can take the full advantage of modern massively parallel computers. It is found that sustaining the full sphere dynamo – driven by convective flows in the absence of the tangent cylinder without imposing any boundary conditions at the center – is more difficult than that in spherical shells. Furthermore, the morphology of the magnetic field generated by the full sphere dynamo is largely dominated by non-dipolar components, indicating the structure of the ancient geomagnetic field prior to the onset of inner-core crystallization would be different from the current geomagnetic field.

Water on the Moon

The Moon is not wet like Earth, and it doesn’t have frozen icecaps like those on Mars. But it might be just a tiny bit damp, both inside and on its surface.

Presumptions of Worth and Pedagogical Imperatives

John Tillson’s thoughtful essay covers tremendous ground in limited space. Tillson does a terrific job highlighting many of the central concerns of religious education both in British and U.S. contexts. The thrust of his argument questions the point of pursuing open-ended discussions on matters that are settled, or as he says, “dead options.” As I understand him, Tillson’s point is that to the degree that an issue is truly open-ended, then Michael Hand’s notion of nondirective instruction, instruction where the goal is consideration of a range of views, is appropriate. Tillson, however, doubts that many religious claims are in fact truly open-ended. Therefore, our choices, he says, are all “unattractive.” According to Tillson, in considering all kinds of religious views and claims we (a) run the risk of having to remain non-committal on matters like holocaust denial or young earth creationism; (b) must also include discussions of atheist and agnostic claims, as well as flying spaghetti monster claims, which (c) inevitably leads to figuring out what to remove from the curriculum in order to make space for all of these open-ended discussions. Instead, he concludes, religious education is best if limited to a survey of the history of religions and perhaps the cultural contributions of religions over time.

The young Earth and the story of the early Archaean rocks of West Greenland

Broadly the science of geology has passed through a number of distinct phases. In the early days attention was focussed on establishing a stratigraphic framework, concentrating on fossils and lithologies—the days of mapping and systematizing of sedimentary successions and the uncovering of the succession of life. Later, in the early twentieth century, geologists became much more interested in igneous rocks. By the 1960s attention turned to the ocean basins, culminating in the acceptance of the paradigm of plate tectonics. At the end of the 1960s, one area of geology that remained relatively little understood was the huge span of time represented by the Precambrian, about 80 per cent of Earth's history. By the 1960s this was changing. Radiometric dating was beginning to show the relative ages of such terranes and new methods of mapping were beginning to be used.

Plate tectonics began in Neoproterozoic time, and plumes from deep mantle have never operated

Archean, Paleoproterozoic, and Mesoproterozoic rocks, assemblages, and structures differ greatly both from each other and from modern ones, and lack evidence for subduction and seafloor spreading such as is widespread in Phanerozoic terrains. Most specialists nevertheless apply non-actualistic plate-tectonic explanations to the ancient terrains and do not consider alternatives. This report evaluates popular concepts with multidisciplinary information, and proposes options. The key is fractionation by ca. 4.45 Ga of the hot young Earth into core, severely depleted mantle, and thick mafic protocrust, followed by still-continuing re-enrichment of upper mantle from the top. This is opposite to the popular assumption that silicate Earth is still slowly and unidirectionally fractionating. The protocrust contained most material from which all subsequent crust was derived, either directly, or indirectly after downward recycling. Tonalite, trondhjemite, and granodiorite (TTG), dominant components of Archean crust, were derived mostly by partial melting of protocrust. Dense restitic protocrust delaminated and sank into hot, weak dunite mantle, which, displaced upward, enabled further partial melting of protocrust. Sinkers enriched the upper mantle, in part maintaining coherence as distinct dense rocks, and in part yielding melts that metasomatized depleted-mantle dunite to more pyroxenic and garnetiferous rocks. Not until ca. 3.6 Ga was TTG crust cool enough to allow mafic and ultramafic lavas, from both protocrust and re-enriched mantle, to erupt to the surface, and then to sag as synclinal keels between rising diapiric batholiths; simultaneously upper crust deformed ductily, then brittly, above slowly flowing hot lower TTG crust. Paleoproterozoic and Mesoproterozoic orogens appear to be largely ensialic, developed from very thick basin-filling sedimentary and volcanic rocks on thinned Archean or Paleoproterozoic crust and remaining mafic protocrust, above moderately re-enriched mantle. Subduction, and perhaps the continent/ocean lithospheric dichotomy, began ca. 850 Ma – although fully modern plate-tectonic processes began only in Ordovician time – and continued to enrich the cooling mantle in excess of partial melts that contributed to new crust. “Plumes” from deep mantle do not operate in the modern Earth and did not operate in Precambrian time.

What’s the Matter with Kansas?: The Development and Confirmation of the Evolutionary Attitudes and Literacy Survey (EALS)

The present survey was designed to assess predominant regional belief systems and the roles these beliefs play in science understanding and attitudes, and curricular effectiveness in colleges and universities. To this end, we created a wide variety of theory-driven subscales (lower order factors) reflecting, for example, exposure to evolutionary material, young earth creationist beliefs, moral and social objections, political ideology, endorsement of intelligent design fallacies, knowledge (and distrust) of the scientific enterprise, and attitudes of evolutionary theory’s relevance in several domains (e.g., sciences and humanities). We also included potentially important demographic variables (e.g., rural upbringing, family size). Finally, we assessed openness to experience, a key facet of personality. Hierarchical Structural Equation Modeling (SEM) analysis showed the 16 constructs to have a theoretically meaningful and quantitatively coherent higher order factor structure. In this large Kansas sample of university students, creationist reasoning and conservative orientation (political and religious) were negatively associated with exposure to evolutionary theory, knowledge about it, and positive attitudes toward its relevance. At the same time, exposure to the theory was positively associated with knowledge and positive attitudes. Importantly, though most Kansas-specific demographic variables (e.g., rural origins) were largely unrelated to outcomes of interest in this university-based sample, the personality factor openness to experience appears to be highly relevant for several higher order factors (e.g., exposure, knowledge and relevance, and creationist reasoning). We close with implications for educators and the next steps in survey development.

Astrocatalysis—Abiogenic synthesis and chemical evolution at pregeological stages of the Earth’s formation

The Earth’s biosphere appeared in a self-organization process along with the appearance of the Solar System. It is shown, based on the methods of self-organization examination and existing knowledge, that major stages of the chemical evolution in the early development of the biosphere include the “cold prehistory of life” in dense molecular nebulae, “pre-planetary chemocoenosis,” “RNA-world” in a circumsolar nebula, and primary biocoenoses of protocells (life) on the planetary bodies. Estimates for carbon in the primordial biosphere on the young Earth’s surface give 2.4 × 1019 kg. The decay of the primordial Earth’s biomass and biogeochemical cycles in 2.5 Myr led to the “planet of bacteria” with 2.0 × 1015 kg of biota in the Proterozoic (at the time of an oxygenated atmosphere). The main parameters (pressure, temperature, and state of catalytic solid phase) are estimated for these stages of the early evolution of life. It is shown that the abiogenic synthesis of the primordial matter was preformed in the Solar System on a grand scale with practically every atom in nanoparticles-catalysts participating. Selection among catalytically active nanoparticles worked towards the ability to synthesize high molecular compounds in a protoplanetary disk. Autocatalysts participated in the preplanetary chemical evolution, beginning from such simple substances as ethylene or glycolaldehyde. Primary synthesis of autocatalysts depended on external sources of energy, e.g., on ultraviolet radiation.

God is in the Data: Epistemologies of Knowledge at the Creation Museum

In contemporary American public culture, interest groups increasingly mobilise social constructionist arguments in order to discredit strains of scientific knowledge. According to Latour [2004. Why Has Critique Run out of Steam? From Matters of Fact to Matters of Concern. Critical Inquiry, 30:225–48], the field of science studies has contributed to this trend by exposing the ways that scientific facts are socially mediated. In this article, I examine how a narrative of social construction is articulated in the Creation Museum, a young earth creationist museum in Northern Kentucky, USA. I compare the epistemology of science in the Creation Museum with that of conspiracy theory and of social constructionist science studies. I examine how, in the Creation Museum, social constructionist critique is combined with a framing of the Bible as a source of factual data. It is argued that science studies, conspiracy theory and creationism overlap in their critiques of the transparency and objectivity of science. However, they diverge in terms of the degree of recursivity they allow.

The Theos/ComRes survey into public perception of Darwinism in the UK: A recipe for confusion

A survey of the general public in the UK, conducted in 2008, suggested that more than half of the British population are unconvinced by Darwinism. That survey, conducted by the polling company ComRes on behalf of the theological think-tank Theos, reported its full findings in March 2009 and found them to be "complex and confused." This paper argues that the confusion identified may have been partly engendered by the way in which the survey questionnaire was constructed and that the survey itself, not simply its respondents, was confused. A source of the confusion, it is argued, could be found, first, in the definitions used for the four positions of young earth creationism, theistic evolution, atheistic evolution and intelligent design. Second, a failure to define the key terms "evolution" and "science," used in some of the survey questions, resulted in responses that were difficult to interpret.

The key role of the redox status in regulation of metabolism in photosynthesizing organisms.

The redox status of the cell is described by the ratio of reduced to non-reduced compounds. Redox reactions which determine the redox state are an essential feature of all living beings on Earth. However, the first life forms evolved under strongly anoxic conditions of the young Earth, and the redox status probably was based on iron and sulphur compounds. Nowadays, redox reactions in cells have developed in strict connection to molecular oxygen and its derivatives i.e. reactive oxygen species (ROS). Oxygen has started to accumulate on the Earth due to oxygenic photosynthesis. All aspects of aerobic life involve ROS, reactive nitrogen species (RNS), antioxidants and redox regulation. Many different redox-active compounds are involved in the complex of redox processes, including pyridine nucleotides, thioredoxins, glutaredoxins and other thiol/disulphide-containing proteins. Redox regulation is integrated with the redox-reactions in photosynthesis and respiration to achieve an overall energy balance and to maintain a reduced state necessary for the biosynthetic pathways that are reductive in nature. It underlies the physiological and developmental flexibility in plant response to environmental signals.

The Fe-rich clay microsystems in basalt-komatiite lavas: importance of Fe-smectites for pre-biotic molecule catalysis during the Hadean eon.

During the Hadean to early Archean period (4.5-3.5 Ga), the surface of the Earth's crust was predominantly composed of basalt and komatiite lavas. The conditions imposed by the chemical composition of these rocks favoured the crystallization of Fe-Mg clays rather than that of Al-rich ones (montmorillonite). Fe-Mg clays were formed inside chemical microsystems through sea weathering or hydrothermal alteration, and for the most part, through post-magmatic processes. Indeed, at the end of the cooling stage, Fe-Mg clays precipitated directly from the residual liquid which concentrated in the voids remaining in the crystal framework of the mafic-ultramafic lavas. Nontronite-celadonite and chlorite-saponite covered all the solid surfaces (crystals, glass) and are associated with tiny pyroxene and apatite crystals forming the so-called "mesostasis". The mesostasis was scattered in the lava body as micro-settings tens of micrometres wide. Thus, every square metre of basalt or komatiite rocks was punctuated by myriads of clay-rich patches, each of them potentially behaving as a single chemical reactor which could concentrate the organics diluted in the ocean water. Considering the high catalytic potentiality of clays, and particularly those of the Fe-rich ones (electron exchangers), it is probable that large parts of the surface of the young Earth participated in the synthesis of prebiotic molecules during the Hadean to early Archean period through innumerable clay-rich micro-settings in the massive parts and the altered surfaces of komatiite and basaltic lavas. This leads us to suggest that Fe,Mg-clays should be preferred to Al-rich ones (montmorillonite) to conduct experiments for the synthesis and the polymerisation of prebiotic molecules.

Geodynamo, Solar Wind, and Magnetopause 3.4 to 3.45 Billion Years Ago

Stellar wind standoff by a planetary magnetic field prevents atmospheric erosion and water loss. Although the early Earth retained its water and atmosphere, and thus evolved as a habitable planet, little is known about Earth's magnetic field strength during that time. We report paleointensity results from single silicate crystals bearing magnetic inclusions that record a geodynamo 3.4 to 3.45 billion years ago. The measured field strength is approximately 50 to 70% that of the present-day field. When combined with a greater Paleoarchean solar wind pressure, the paleofield strength data suggest steady-state magnetopause standoff distances of < or = 5 Earth radii, similar to values observed during recent coronal mass ejection events. The data also suggest lower-latitude aurora and increases in polar cap area, as well as heating, expansion, and volatile loss from the exosphere that would have affected long-term atmospheric composition.

Evolution explained: Darwin's greatest modern advocate speaks out

In The God Delusion Richard Dawkins stated that he was not writing with the intent of converting committed theists but, rather, with the aim of influencing those who were undecided between belief and atheism. After reading The Greatest Show on Earth, I imagine that Dawkins is likewise trying to convince the undecided rather than the hard-core creationists. On the opening page he compares the teacher of evolution to teacher of Roman history whose class is continually disrupted by a baying pack of ignoramuses who vociferously assert that the Roman empire did not exist. Some might wonder whether less confrontational tone would be more effec- tive in getting the reader on board. I am not so sure. Dawkins gives the example of Wendy Wright, the president of 'Concerned Women for America', who was inter- viewed for the Channel Four documentary The Genius of Charles Darwin. She re- peatedly questions the existence of intermediate fossils, whilst Dawkins repeat- edly ripostes that they are in the museums if only she would care to look. When one listens to Wendy Wright and the many people like her (see some of the risible crea- tionist videos on YouTube) one feels that they are lost cause. However, for anyone who is unsure about the case for evolution and is willing to actually read about the evidence, then The Greatest Show on Earth is brilliant exposition. Each chapter deals with different aspect of the case and then asks how this could be explained by young earth creationism (creationists who believe that

Darwin's Straw God Argument

In the controversy between Darwinian evolution and Intelligent Design, the fonver is commonly portrayed as science and the latter as theology or phitosophy. Yet Charles Darwin's "one long argument" in The Origin of Species was heavily theological. In particular, Darwin argued that the geographical distribution of living things, the fossil record, vestigial organs, and homologies were "inexplicabte on the theory of creation," but made sense on his theory of descent with modification. In this context, "The theory of creation" did not imply young-earth creationism, but a God conceived by Darwin to create all species separately, arbitrarily, and perfectly. In the many instances when the evidence was not sufficient to support his positive case for descent with modification, Darwin would simply declare that the only altemative-the "theory of creation"-was not a scientific explanation. Darwin's followers often argue similarly. Thus, arguments for Darwinian evolution, in both its ordinal and modem forms, are commonly bound up with arguments from theology and philosophy.

Why didn't the young Earth freeze?

Why didn't the young Earth freeze?

Meteorite Kr in Earth’s Mantle Suggests a Late Accretionary Source for the Atmosphere

Noble gas isotopes are key tracers of both the origin of volatiles found within planets and the processes that control their eventual distribution between planetary interiors and atmospheres. Here, we report the discovery of primordial Kr in samples derived from Earth's mantle and show it to be consistent with a meteorite or fractionated solar nebula source. The high-precision Kr and Xe isotope data together suggest that Earth's interior acquired its volatiles from accretionary material similar to average carbonaceous chondrites and that the noble gases in Earth's atmosphere and oceans are dominantly derived from later volatile capture rather than impact degassing or outgassing of the solid Earth during its main accretionary stage.