scholarly journals Quantifying the origins of life on a planetary scale

2016 ◽  
Vol 113 (29) ◽  
pp. 8127-8132 ◽  
Author(s):  
Caleb Scharf ◽  
Leroy Cronin
Keyword(s):  
Parameter Estimation ◽  
Chemical Evolution ◽  
Planetary Systems ◽  
Origins Of Life ◽  
Bayesian Approaches ◽  
Planetary Scale ◽  
The Earth ◽  
Open Questions ◽  
Impact Ejecta ◽  
Molecular Complexity

A simple, heuristic formula with parallels to the Drake Equation is introduced to help focus discussion on open questions for the origins of life in a planetary context. This approach indicates a number of areas where quantitative progress can be made on parameter estimation for determining origins of life probabilities, based on constraints from Bayesian approaches. We discuss a variety of “microscale” factors and their role in determining “macroscale” abiogenesis probabilities on suitable planets. We also propose that impact ejecta exchange between planets with parallel chemistries and chemical evolution could in principle amplify the development of molecular complexity and abiogenesis probabilities. This amplification could be very significant, and both bias our conclusions about abiogenesis probabilities based on the Earth and provide a major source of variance in the probability of life arising in planetary systems. We use our heuristic formula to suggest a number of observational routes for improving constraints on origins of life probabilities.

scholarly journals Bioastronomy (Report of Iau Commission 51)

1991 ◽  
Vol 21 (1) ◽  
pp. 599-606
Author(s):  
Marx George
Keyword(s):  
Solar System ◽  
Chemical Evolution ◽  
Computer Technology ◽  
Large Scale ◽  
Planetary Systems ◽  
Origins Of Life ◽  
Systematic Survey ◽  
Radio Signals

In the recent years, science have become able to give more definite answers to the questions of the abundance of planetary systems, of the pathways of chemical evolution leading to the emergence of simple self-reproducing structures, to the origins of life within and beyond the Solar System. At the same time a new question has been raised: the duration of life-sustaining environment, what is a prerequisit for the emergence of technology. Thanks to the fast progress of computer technology, the search for intelligent radio signals has become affordable. The number of observatories participating in this venture increases rapidly. Preparations are in progress for a large scale systematic survey.

Chemical evolution of interstellar dust, comets and the origins of life

1989 ◽  
Vol 14 (2) ◽  
pp. 103-131 ◽  
Author(s):  
J. Mayo Greenberg ◽  
Nansheng Zhao ◽  
Joniek Hage
Keyword(s):  
Chemical Evolution ◽  
Interstellar Dust ◽  
Origins Of Life

Medianatures

2018 ◽  
Vol 9 (1) ◽  
pp. 103-106
Author(s):  
Jussi Parikka
Keyword(s):  
Planetary Scale ◽  
Nature And Culture ◽  
The Earth ◽  
Visual Technologies

The article outlines the concept of medianatures. The term is a neologism and in debt to Donna Haraway’s rather eloquent and important coinage naturecultures that already functioned to mark the constant co-becomings of supposedly separated spheres of nature and culture. Medianatures is a further elaboration that elaborates the tie between the earth materialities that are mobilized for technological infrastructures, visual technologies, applications and devices, and the onto- epistemological stance that then feeds back into understanding those planetary scale earth materialities in the first place: the techniques of vision, observation, calculation, and circulation that are part of the governance of the earth and its various localities.

Prebiotic studies on the interaction of zirconia nanoparticles and ribose nucleotides and their role in chemical evolution

2021 ◽  
Vol 20 (2) ◽  
pp. 142-149
Author(s):  
Avnish Kumar Arora ◽  
Pankaj Kumar
Keyword(s):  
Electron Microscopy ◽  
Metal Oxide ◽  
Metal Oxides ◽  
Chemical Evolution ◽  
Ribonucleic Acid ◽  
Zirconium Oxide ◽  
Origins Of Life ◽  
Neutral Ph ◽  
Interaction Studies

AbstractStudies on the interaction of biomolecules with inorganic compounds, mainly mineral surfaces, are of great concern in identifying their role in chemical evolution and origins of life. Metal oxides are the major constituents of earth and earth-like planets. Hence, studies on the interaction of biomolecules with these minerals are the point of concern for the study of the emergence of life on different planets. Zirconium oxide is one of the metal oxides present in earth's crust as it is a part of several types of rocks found in sandy areas such as beaches and riverbeds, e.g. pebbles of baddeleyite. Different metal oxides have been studied for their role in chemical evolution but no studies have been reported about the role of zirconium oxide in chemical evolution and origins of life. Therefore, studies were carried out on the interaction of ribonucleic acid constituents, 5′-CMP (cytidine monophosphate), 5′-UMP (uridine monophosphate), 5′-GMP (guanosine monophosphate) and 5′-AMP (adenosine monophosphate), with zirconium oxide. Synthesized zirconium oxide particles were characterized by using vibrating sample magnetometer, X-Ray Diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy. Zirconia particles were in the nanometre range, from 14 to 27 nm. The interaction of zirconium oxide with ribonucleic acid constituents was performed in the concentration range of 5 × 10−5–300 × 10−5 M. Interaction studies were carried out in three mediums; acidic (pH 4.0), neutral (pH 7.0) and basic (pH 9.0). At neutral pH, maximum interaction was observed. The interaction of zirconium oxide with 5′-UMP was 49.45% and with 5′-CMP 67.98%, while with others it was in between. Interaction studies were Langmurian in nature. Xm and KL values were calculated. Infrared spectral studies of ribonucleotides, metal oxide and ribonucleotide–metal oxide adducts were carried out to find out the interactive sites. It was observed that the nitrogen base and phosphate moiety of ribonucleotides interact with the positive charge surface of metal oxide. SEM was also carried out to study the adsorption. The results of the present study favour the important role of zirconium oxide in concentrating the organic molecules from their dilute aqueous solutions in primeval seas.

scholarly journals The interiors of Uranus and Neptune: current understanding and open questions

2020 ◽  
Vol 378 (2187) ◽  
pp. 20190474 ◽  
Author(s):  
Ravit Helled ◽  
Jonathan J. Fortney
Keyword(s):  
Solar System ◽  
Internal Structure ◽  
Planetary Systems ◽  
Space Missions ◽  
Current Understanding ◽  
Interior Structure ◽  
Distinct Class ◽  
Open Questions

Uranus and Neptune form a distinct class of planets in our Solar System. Given this fact, and ubiquity of similar-mass planets in other planetary systems, it is essential to understand their interior structure and composition. However, there are more open questions regarding these planets than answers. In this review, we concentrate on the things we do not know about the interiors of Uranus and Neptune with a focus on why the planets may be different, rather than the same. We next summarize the knowledge about the planets’ internal structure and evolution. Finally, we identify the topics that should be investigated further on the theoretical front as well as required observations from space missions. This article is part of a discussion meeting issue ‘Future exploration of ice giant systems’.

Iron-Catalyzed Cross-Coupling: Mechanistic Insight for Rational Applications in Synthesis

Synthesis ◽  
2017 ◽  
Vol 49 (15) ◽  
pp. 3269-3280 ◽  
Author(s):  
Tobias Parchomyk ◽  
Konrad Koszinowski
Keyword(s):  
Catalyst Activity ◽  
Cross Coupling ◽  
Short Review ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Open Questions ◽  
Carbon Carbon Bonds ◽  
Bond Homolysis ◽  
Molecular Complexity ◽  
Synthetic Application

Iron-catalyzed cross-coupling reactions provide a promising way to form new carbon–carbon bonds and build up molecular complexity. This short review presents recent advances in the synthetic application of these reactions as well as in the elucidation of their mechanism. It also highlights remaining problems and aims at pointing out ways toward possible remedies.1 Introduction2 Synthesis: Recent Accomplishments and Unsolved Problems2.1 Substrate Scope: Electrophiles2.2 Substrate Scope: Nucleophiles2.3 Catalyst Activity and Chemoselectivity2.4 Stereoselectivity2.5 Practical Aspects3 Mechanism: Recent Insights and Open Questions3.1 Transmetallation and Activation of the Iron Precatalyst3.2 Coupling via Oxidative Addition and Reductive Elimination3.3 Coupling via C–X Bond Homolysis and Radical Rebound3.4 Coupling via Bimolecular C–X Bond Homolysis3.5 Other Reactions of Organoiron Species with Electrophiles4 Toward Rational Reaction Improvement5 Conclusion

The role of the Microbial Conveyor Belt on Earth´s system resilience

2021 ◽  
Author(s):  
Mireia Mestre ◽  
Juan Höfer
Keyword(s):  
Human Impacts ◽  
Conveyor Belt ◽  
Earth System ◽  
Planetary Scale ◽  
Microbial Biogeography ◽  
The Earth ◽  
System Resilience ◽  
Global Biogeochemical Cycles

<p>Despite being major players on the global biogeochemical cycles, microorganisms are generally not included in holistic views of Earth’s system. The Microbial Conveyor Belt is a conceptual framework that represents a recurrent and cyclical flux of microorganisms across the globe, connecting distant ecosystems and Earth compartments. This long-range dispersion of microorganisms directly influences the microbial biogeography, the global cycling of inorganic and organic matter, and thus the Earth system’s functioning and long-term resilience. Planetary-scale human impacts disrupting the natural flux of microorganisms pose a major threat to the Microbial Conveyor Belt, thus compromising microbial ecosystem services. Perturbations that modify the natural dispersion of microorganisms are, for example, the modification of the intensity/direction of air fluxes and ocean currents due to climate change, the vanishing of certain dispersion vectors (e.g., species extinction or drying rivers) or the introduction of new ones (e.g., microplastics, wildfires). Transdisciplinary approaches are needed to disentangle the Microbial Conveyor Belt, its major threats and their consequences for Earth´s system resilience.</p>

scholarly journals Planet forming disks, debris disks and the Solar System

2019 ◽  
Vol 15 (S350) ◽  
pp. 207-215
Author(s):  
Inga Kamp
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
Planetary Systems ◽  
Theoretical Work ◽  
Structure Evolution ◽  
Debris Disks ◽  
Physical Processes ◽  
Disk Structure ◽  
Open Questions ◽  
Evolution Modeling

AbstractVLT instruments and ALMA with their high spatial resolution have revolutionized in the past five years our view and understanding of how disks turn into planetary systems. This talk will briefly outline our current understanding of the physical processes occurring and chemical composition evolving as these disks turn into debris disks and eventually planetary systems like our own solar system. I will especially focus on the synergy between disk structure/evolution modeling and astrochemical laboratory/theoretical work to highlight the most recent advances, and open questions such as (1) how much of the chemical composition in disks is inherited from molecular clouds, (2) the relevance of snowlines for planet formation, and (3) what is the origin of the gas in debris disks and what can we learn from it. For each of the three, I will outline briefly how the combination of theory/lab astrochemistry, astrophysical models and observations are required to advance our understanding.

Origins of Life: Open Questions and Debates

2017 ◽  
Author(s):  
André Brack
Keyword(s):  
Rna World ◽  
Stochastic Approach ◽  
Origins Of Life ◽  
Test Tube ◽  
Chemical System ◽  
Small Scale ◽  
Random Errors ◽  
Critical Feature ◽  
Open Questions ◽  
Simple Molecules

Stanley Miller demonstrated in 1953 that it was possible to form amino acids from methane, ammonia, and hydrogen in water, thus launching the ambitious hope that chemists would be able to shed light on the origins of life by recreating a simple life form in a test tube. However, it must be acknowledged that the dream has not yet been accomplished, despite the great volume of effort and innovation put forward by the scientific community. A minima, primitive life can be defined as an open chemical system, fed with matter and energy, capable of self-reproduction (i.e., making more of itself by itself), and also capable of evolving. The concept of evolution implies that chemical systems would transfer their information fairly faithfully but make some random errors. If we compared the components of primitive life to parts of a chemical automaton, we could conceive that, by chance, some parts self-assembled to generate an automaton capable of assembling other parts to produce a true copy. Sometimes, minor errors in the building generated a more efficient automaton, which then became the dominant species. Quite different scenarios and routes have been followed and tested in the laboratory to explain the origin of life. There are two schools of thought in proposing the prebiotic supply of organics. The proponents of a metabolism-first call for the spontaneous formation of simple molecules from carbon dioxide and water to rapidly generate life. In a second hypothesis, the primeval soup scenario, it is proposed that rather complex organic molecules accumulated in a warm little pond prior to the emergence of life. The proponents of the primeval soup or replication first approach are by far the more active. They succeeded in reconstructing small-scale versions of proteins, membranes, and RNA. Quite different scenarios have been proposed for the inception of life: the RNA world, an origin within droplets, self-organization counteracting entropy, or a stochastic approach merging chemistry and geology. Understanding the emergence of a critical feature of life, its one-handedness, is a shared preoccupation in all these approaches.

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