In most cases, the newly formed elements that are not incorporated into the neutron star or black hole are dispersed back into the interstellar medium and become incorporated into the next generation of stars and planets Whittet, Life cycle of stars, for both Sun-like stars and massive stars. Protoplanetary disks are diffuse regions of gas and dust and are the eventual birthplaces of stellar and planetary systems. During the gravitational collapse of a molecular hydrogen cloud, conservation of angular momentum causes the cloud's rotation to increase, and the rotation causes the cloud to flatten into a disk.
The center of the disk contains the newly forming star, and the disk is the site of planet formation. Planetary bodies are widely believed to have formed through the method of core accretion Ida and Lin, Under this paradigm, dust accretes over time to produce rocky bodies known as planetesimals that range from kilometer size to approximately the size of Earth's Moon. These bodies interact gravitationally with each other, colliding and accreting to produce planetary embryos Moon- to Mars-sized solid bodies or being broken apart by violent collisions.
An alternative planet formation model that has been hypothesized is that of gravitational instability Zel'Dovich, ; Boss, In the instability model, protoplanetary disks fragment during the collapse of the disk, creating high-density regions that rapidly pull in surrounding material to form planetary bodies.
This model, however, has not been widely adopted by the modeling community and encounters difficulties in producing the observed architecture of extrasolar planetary systems. As such, we will focus on the accretion model. In the planetary accretion model, planets with relatively high metallic and rocky content, such as Mercury and Earth, are expected to form closer to their host star. Conversely, planets with greater volatile content molecules that have low boiling points , such as the giant planets of the outer Solar System, are expected to form farther from their host star.
The latter group of planets can become much more massive than their rocky counterparts due to addition of extra mass in the form of accreted volatiles. This explanation is consistent with—and historically driven by—the arrangement of planets in the Solar System: smaller, rocky planets exist closer to the star and larger, volatile-rich planets farther from the star. However, Jupiter-mass and Neptune-mass exoplanets have been found closer to their host than Mercury is to the Sun Butler et al. Combined, core accretion and orbital migration form the general framework for planet formation, both within our solar system and within extrasolar planetary systems Kley and Nelson, Two dominant models have emerged under the planetary accretion paradigm to explain the formation of planets and long-term evolution of the Solar System: the Grand Tack model, which focuses on planet formation Walsh et al.
Both models involve large-scale migration of the giant planets before settling in their current orbits and can explain a variety of features of the Solar System. However, they focus on very different time periods Nice occurred approximately million years after the Solar System formed, while the Grand Tack occurred within the first 5 million years. The two models also have somewhat different end results in that the Nice model reproduces the outer Solar System well, while the Grand Tack reproduces the inner Solar System. The Grand Tack model addresses formation events that occurred in the earliest stages of the formation of the planets within the Solar System.
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Under this model, Jupiter and subsequently Saturn began their formation considerably closer to the Sun than they are now approximately 3. Once large enough, both protoplanets began to experience type II migration wherein they were coupled to the gas disk and slowly migrated inward, along with the gas.
This migration brought the bodies in to 1. As they migrated outward, they encountered Uranus and Neptune and caused the outward migration of these two planets to their current orbits. The Grand Tack model has the benefit of explaining the structure and composition of the asteroid belt. There are two very different types of asteroids in the asteroid belt—ordinary chondrites and carbonaceous chondrites—which have very different compositions and therefore must have formed in different locations.
According to the Grand Tack model, the giant planets scatter planetesimals throughout the disk as they migrate outward from 1. Some of these are scattered inward, which results in the introduction of carbonaceous chondrites to the asteroid belt and explains the presence of two vastly different types of asteroids within the asteroid belt—ordinary chondrites in the inner asteroid belt and carbonaceous chondrites in the outer belt.
The Grand Tack model allows for the combination of the two types in one location. The formation of Mars has been difficult to simulate correctly, as most models produce planets that are too massive Wetherill, ; O'Brien et al. One solution to this problem is to truncate the disk of planetesimals that accrete to produce the terrestrial planets at 1 AU Hansen, The Grand Tack model provides a mechanism to achieve this, as the presence of a still-forming Jupiter at 1.
The Nice model, on the other hand, is focused on the evolution of the Solar System and results from the giant planets Jupiter, Saturn, Neptune, and Uranus initially being located farther from the Sun and closer to each other. Dynamical interactions with a large remnant planetesimal population result in orbital instabilities for Jupiter and Saturn.
These orbital instabilities resulted in gravitational interactions with Uranus and Neptune, also affecting their orbits. Subsequent gravitational interactions between the giant planets and a planetesimal disk on the outer edges of the Solar System not only produce the influx of impactors observed in the inner Solar System during the Late Heavy Bombardment LHB period see Section 3. The Nice model can also explain not only the structure of the asteroid belt but also some of the compositional variations observed therein Levison et al.
This initial model has been modified, with the giant planets being suggested to have initially started in a quadruple resonance Levison et al. Combined together, the Nice and Grand Tack models may represent the formation and evolution pathway of the planets within our solar system and potentially within other extrasolar systems.
For further details regarding terrestrial planet formation models, see Morbidelli et al. See also Chapter 6 for more information on our current knowledge of planets in other solar systems. Once a planet forms under any model there can be further changes that result in the differentiation of elements between layers Chambers, During this differentiation, relatively dense components such as iron, nickel, or metallic hydrogen tend to sink to the center to form the planet's core, whereas relatively less dense materials such as silica and gases become preferentially incorporated into the mantle and crustal layers above.
Differentiation plays a major role in the distribution of elements in a planetary body. Earth formed via accretion see Section 3. The age of Earth was established based on the combination of both Earth-based and meteoritic samples. Earth-based evidence includes the age of the oldest minerals currently persevered on Earth's surface 4. Meteoritic evidence includes the age of the first solids to condense within the Solar System, known as calcium-aluminum inclusions 4. Earth accreted and differentiated over a 10— million-year time period, based on the hafnium- tungsten Hf- W isotope system.
Hafnium is a lithophile i. Tungsten, on the other hand, is a siderophile and as such portioned into the core during Earth's formation. Thus, the observed W enrichment in Earth's crust relative to other W and Hf isotopes must be a result of Hf decay, meaning formation and differentiation must have occurred while Hf was still active and present within the system. Thus, the formation of Earth commenced no earlier than 10 million years after the formation of the Solar System Kleine et al. There is some debate about whether a rapid accretion 10—30 million years or slower accretion 50— million years occurred, based on the timing of the Moon-forming impact discussed below.
This issue currently remains unresolved. The Hadean marks the first geological eon in Earth's history and spans the period from the end of the accretion to the beginning of the Archean eon at 3. During the Hadean, impactors pummeled proto-Earth. The most dramatic event during this period occurred within the first million years of Earth's history. According to the most widely accepted hypothesis, this is when young Earth collided with a Mars-sized object, which led to the formation of the Moon Canup and Asphaug, Heat from the impact left Earth's surface in a molten state, and due to the lack of an atmosphere immediately following impact, cooling occurred quickly.
Within million years a solid basaltic crust reformed. Steam escaping from the crust and gases released from volcanoes generated the prebiotic atmosphere and contributed to the formation of oceans see Section 3. Eventually, delivery of the late veneer material essentially ceased. According to the most well-known, though not universally accepted, hypothesis, this terminated with the LHB period between 4. Some geological models suggest that Earth could not have been continuously habitable during this period because the impacts would have sterilized the planet Maher and Stevenson, However, there is some debate as to the global lethality of such impacts Sleep et al.
The emergence of life as we know it requires the presence of a variety of volatile elements and species. However, Earth's feeding zone is believed to have been dry and depleted in volatiles species that readily enter into the gaseous phase due to a lower temperature of vaporization , especially water based on the volatile-poor composition of the innermost asteroids. As such, delivery of these species or their precursors needed to occur during the formation and early evolution of Earth.
Water delivery is understood to have occurred throughout the formation of Earth, primarily through the accretion of asteroidal material, with comets and other sources providing limited water. Organics were delivered via asteroids, with a very small amount being derived from cometary material. Given their ice-rich composition, comets were originally suggested as the primary source of Earth's water e. This idea has since been largely discredited due to the low probability of cometary collisions with Earth Morbidelli et al.
Although water-poor in comparison with comets, asteroidal material has also been suggested as a water source, given its higher probability of colliding with Earth Morbidelli et al. This scenario has been altered somewhat by the Grand Tack model discussed previously, see Section 3.
Currently, our understanding is that the bulk of Earth's current water was derived from material analogous to asteroids and planetary embryos, delivered early in Earth's history, and later from larger planetary embryos that formed the outer, volatile-rich regions of the protoplanetary disk.
This model has traditionally been difficult to simulate Raymond et al. Although it is unlikely that a significant fraction of the earliest water delivered would be retained, the later water delivery by embryos would supply sufficient water to account for Earth's water budget. Impacts from comets and asteroids delivered a variety of organics to early Earth, even though they provided only a very small fraction of Earth's water budget Morbidelli et al. The interstellar medium, asteroids, and meteorites have been shown to host organics necessary for life Sephton, ; Ehrenfreund and Cami, ; Pizzarello and Shock, The inventory of organics synthesized from the elements in interstellar space contains at least identified species, including the simplest amino acid, glycine C 2 H 5 NO 2.
Additionally, formaldehyde, cyanide, acetaldehyde, water, and ammonia—all precursors in different synthesis pathways for amino acids—have been detected. Amino acids are molecules that contain an amine group, a carboxylic acid group, and a side chain, which play a prominent role in modern biology as the primary building blocks of proteins. During the formation of the Solar System, some of this interstellar organic material would have been integrated in the presolar nebula the gas cloud from which the Solar System condensed—see Section 3.
Impacts of these objects specifically asteroids delivered volatile organics to ancient Earth Chyba and Sagan, Sample return missions provide some of the best data about the composition of early impactors, as returned samples will have the most pristine records of the earliest Solar System Matzel et al. Additionally, comets likely contributed small amounts of carbonaceous material during the heavy bombardment 4. A surprise from the initial analysis of the Stardust samples retrieved from the comet Wild 2 was that the mineralogy was similar in composition to inner Solar System asteroids Ishii et al.
Other major extraterrestrial sources of carbon include interplanetary dust particles and carbonaceous meteorites Chyba et al. The Japan Aerospace Exploration Agency JAXA mission Hayabusa returned samples from the asteroid Itokawa, the study of which confirmed that asteroids are also similar in composition to ordinary meteoritic chondrites Tomoki et al. These extraterrestrial sources would have added to the endogenous inventory of carbon already existing on early Earth Chyba and Sagan, Phosphorus is often the limiting resource for biological systems on Earth, as it is essential for all known life, but the geochemical cycling of phosphate is slow, and most phosphate minerals are insoluble Pasek, A challenge for prebiotic chemistry is, therefore, to find sources for reactive and soluble phosphorus Bryant and Kee, ; Pasek, In particular, meteorites may have been an important source of reactive phosphorus—such as the P-bearing ions pyrophosphate and triphosphate, key components for metabolism in modern life—a likely requirement for the emergence of life Pasek and Lauretta, Once delivered to proto-Earth and early Earth, geological activity provided many of the volatiles necessary for the emergence of life.
In particular, Earth's early atmosphere formed via volcanic degassing see Section 3. This composition was at least mildly reducing, although how reducing it was is debated Tian et al. Reactions of these volatiles in a weakly reducing early atmosphere could have produced molecular precursors to life see Section 3. In addition, recycling of bioessential elements such C, N, O, and P on modern Earth is important to sustained habitability see Chapter 5 and may have been crucial in the early development of life on Earth Sleep, There is evidence that life on Earth was well established as early as 3.
However, the ages of the most ancient fossils are difficult to determine and typically subject to debate e. If life was in fact thriving as early as 3. The first is that life may have originated before or during the LHB and survived this tumultuous period in the early history of Earth.
This viewpoint is strengthened by evidence that indicates Earth may never have been fully sterilized during the LHB Abramov and Mojzsis, A second possibility is that, just after the LHB, the conditions on primitive Earth were conducive to the rapid emergence of life Oberbeck and Fogleman, ; Sleep et al. Because He burning gives off more energy than H burning, the Sun has become brighter over the course of Earth's geological history. This leads to the faint young Sun paradox: a planet with Earth's current atmospheric composition orbiting the faint early Sun would have had cold global temperatures that would have frozen all water at the surface of the planet, yet there is evidence for liquid water on early Earth.
One resolution is that the early atmosphere was probably very different from the atmosphere of modern Earth and may have contained higher levels of greenhouse gases Pavlov et al. This is still an area of extensive research, and no definite theory has been widely accepted. By the start of the Archean, global oceans covered most of the surface of Earth. Evidence of mineral interactions with water suggest that oceans may have started to form by 4.
Water would have degassed along with volatiles such as N 2 and CO 2 to form the primitive atmosphere. Condensation of the steam produced from volcanic degassing would have occurred as Earth cooled and led to the formation of global oceans. However, it is widely agreed that the primary source of water on Earth was delivery by material similar to C-type asteroids Morbidelli et al. These stages are shown in Fig. Events of the five described stages could have been overlapping in time and space, and it is often difficult, if not impossible, to uniquely assign particular processes to one stage.
General schemes of possible stages of prebiotic evolution. Credit: K. Adamala, adapted from scenario proposed by Eigen and Schuster, To understand how life could have originated, we need to understand the types of environments that were present on Earth, the energy sources and raw materials that were available, the chemical reactions that might have been possible given the environmental conditions, and the processes that would have set a sequence of events in motion that resulted in the origin of life.
Section 3. Each would have provided unique sources of energy, specific raw materials, and different mechanisms to facilitate chemical reactions. Apart from organic synthesis, three broad categories of reactions would have been required, including concentration of ingredients from a dilute medium, selection of biochemically useful compounds, and polymerization of monomers. Several possible microenvironments are listed in Table 1. The various sources of energy, the availability of raw materials, and the numerous types of chemical processes that could have taken place on early Earth are discussed in the sections below.
Table 1. This table is not meant to be exhaustive but rather to list commonly discussed settings and requirements. All these environments, as well as many others, could have been interconnected by various mixing processes. Energy would have been required for a variety of necessities for the origin of life: the synthesis of important prebiotic precursors, concentration of potentially reactive solutes, energetically unfavorable polymerization reactions, global mixing of prebiotic reactants and products, and metabolisms Deamer, ; Deamer and Weber, This energy could have been provided in various environments from ultraviolet UV and visible light see Chapter 7 for an introduction to the electromagnetic spectrum , chemical reduction—oxidation redox processes, and geothermal heat.
Visible and UV radiation could only have been available near the ocean's surface or on land, since UV radiation cannot penetrate far into water. Geothermal energy could have been available at hydrothermal sites such as vents on the seafloor and provided both heat to increase rates of reactions as well as redox gradients Simoncini et al. See Section 4. These redox gradients provide both reduced and oxidized compounds in relatively close physical and temporal space.
This redox disequilibrium creates the potential for energy-releasing redox reactions to occur. In fact, all modern organisms drive metabolic synthesis reactions by using electrochemical energy from redox reactions. Even photosynthetic organisms, which derive their energy from sunlight, use redox reactions as part of the mechanism by which this energy is harnessed see Chapter 4. Some researchers have therefore suggested that early metabolisms developed in environmental settings where redox gradients occur naturally Baross and Hoffman, ; Martin and Russell, Lateral transport and mixing could have brought together reaction products from various settings around the globe.
One of the most commonly used definitions of life is that it is a chemical reaction system capable of Darwinian evolution see Chapter 2. The complex chemical reaction systems that exist today must have originated as a result of a long series of simpler, more primitive processes. The initial raw materials for these chemical reactions are the individual chemical elements, which react with each other and combine to form molecules. While many molecules, including organic carbon molecules, can form abiotically without the intervention of life , one of the characteristics of life is the presence of highly complex organic carbon compounds that are not known to form by any nonliving processes see Chapter 7 for more detail.
Theories about the origin of life must therefore explain how complex organic molecules could have formed see Section 3. The characteristics of the microenvironments on early Earth would have directly influenced the type of chemical processes—prebiotic chemical reactions—that could have taken place and led to the origin of life.
The environment of prebiotic reactions on Earth is considered to be predominately aqueous Nisbet and Sleep, Some processes are postulated to take place in the gas phase in the atmosphere Dobson et al. The prebiotic ocean was radically different from the modern ocean Derry and Jacobsen, Some have suggested that, unlike the oceans of today, the early ocean was more alkaline, lower in Mg and Ca cations, and lower in NaCl Kempe and Degens, Others have concluded that the early ocean was similar to those of the present, perhaps even mildly more acidic given the higher abundance of atmospheric CO 2 gas Grotzinger and Kasting, Large gradients in pH and alkalinity probably occurred in the vicinity of hydrothermal vents Holm, On modern Earth, vent fluids can range from pH 2 to pH 11, depending on whether they are driven by magmatic heating or serpentinization, and it is likely that both processes occurred under prebiotic conditions.
Many prebiotic chemistry processes may have occurred in lagoons or pools, where tides drove cyclic changes of concentrations that provided the increase of concentration necessary for increasing the yields and efficiency of the prebiotic reactions Nelson et al. Another setting that has been gaining support in recent years is the oceanic crust with its associated hydrothermal alteration zones.
Multiple experimental and theoretical studies have demonstrated that organic synthesis, polymerization, and selection of compounds can occur under hydrothermal conditions Baross and Hoffman, ; Martin et al. The advantages of subaerial lagoons and hydrothermal systems were perhaps combined in terrestrial hot springs Mulkidjanian et al. Importantly, hydrothermal vents may exist on icy moons such as Enceladus Glein et al. If life exists on those bodies, then it would underscore the importance of hydrothermal processes in prebiotic chemistry.
The range of temperatures available for prebiotic reactions vary greatly. Also, the temperatures postulated for the actual origin of life vary, some hypotheses favoring a hot environment Miller and Lazcano, , others favoring a cold environment Bada and Lazcano, The average temperature on prebiotic Earth may have been higher than it is today Arrhenius, , but this is a topic of current debate. Given the lower luminosity of the young Sun and uncertainties about the abundance of greenhouse gases and continental area at the time, it is also possible that Earth cooled down relatively quickly to lower temperatures after its formation Sleep et al.
For prebiotic chemistry, the average surface temperature is less important than the occurrence of liquid water at the surface. Evidence for liquid water dates back to 4. Favorable temperatures for specific reactions could have been encountered in environmental niches, such as in local ice caps or hydrothermal systems. In all modern life-forms, enzymes lower the activation energy of numerous biochemical reactions necessary to sustain the living cell. In a world of prebiotic chemistry, none of those enzymes would have been available; hence important steps in the origin of life would have had to take advantage of a nonbiological catalytic mechanism or arise with the slower kinetics of uncatalyzed reactions.
Nonbiological catalysts that would have been available on prebiotic Earth include naturally occurring minerals such as clays Meng et al. Other mechanisms that facilitated reactions could have been the concentration of reactants in compartments or on surfaces, and evaporation. Examples of concentrating processes include progressive shrinkage of brine pockets in sea ice during freezing Kanavarioti et al.
All these mineralogical and hydrological subsettings would have exchanged reactants and products via various mixing processes, which would include ocean and atmospheric circulation; thermal convection in the subseafloor; tidal interaction; and catastrophic events such as impacts, seismic activity, or volcanic eruptions.
Stereoselectivity is a key feature of many modern biological reactions see Chapter 4 , but it is unknown at what stage in the origin of life stereoselectivity arose. There are numerous studies on obtaining stereoselective enantiomerically enriched products in putative prebiotic reactions between monomers Popa, Even the smallest possible enantiomeric enrichment could be significant in prebiotic synthesis, as it could build up over time or in subsequent reactions Mason, Some, however, consider that, on prebiotic Earth, obtaining any enantiomerically enriched products was impossible, and the abiogenic synthesis was either achiral or occurred elsewhere Salam, In mixtures of products from processes that researchers agree are abiotic i.
Some inorganic processes, such as polarized light Balavoine et al. When some chiral asymmetry is introduced to the pool of substrates or catalysts, it can be amplified in the subsequent reactions, resulting in almost enantiomerically pure mixtures Soai et al. However, given the fact that prebiotic processes likely had a huge reaction volume and many hundreds of years to accumulate products, single-digit percentage yields may have been sufficient. Also, in prebiotic processes, several analog compounds often have similar activity.
Often prebiotic reactions result in a whole class of compounds, different species with a certain functional group, rather than a single well-defined product structure. The low yields and lack of selectivity are among the major problems of prebiotic chemistry Sutherland and Whitfield, Modern biochemical processes, and most probably those of the first cell metabolism, are very selective.
This high selectivity is achieved by using advanced enzymatic machinery. One of the biggest challenges of prebiotic chemistry synthesis of building blocks and protobiology assembling the simplest biochemical reaction cycles is to control the selectivity of the syntheses. A recently highlighted example of such a niche is the pore space of rocks that preferably adsorb long over short oligonucleotides Kreysing et al. Prebiotic chemistry is the study of chemical reactions that result in the formation of organic carbon molecules, without the involvement of biological catalysts.
This covers chemical reactions that take place under conditions such as those of the primordial Earth environment or the interstellar medium, where organic molecules can be synthesized from inorganic building blocks Guillemin et al.
Organic carbon molecules, such as precursors to lipids, nucleotides, amino acids, and carbohydrates, were necessary building blocks for the origin of life, but there is little agreement as to what the principal source would have been McCollom, ; Trainer, One of the first origin-of-life experiments, the Miller-Urey experiment Miller, , produced amino acids and other organic compounds by passing an electric charge through a mixture of gases that were considered to be components of Earth's early atmosphere at the time of the experiment H 2 O, CH 4 , and H 2 , see Section 3.
Impactors and interplanetary dust could also have delivered organic material Chyba and Sagan, ; Pizzarello and Shock, ; Schmitt-Kopplin et al. The chemical processes that occur in hydrothermal vents, particularly those driven by serpentinization, are known to produce organic compounds through abiotic reactions. This could have resulted in the abiotic production of formate, acetate, methane, and larger hydrocarbons, including potentially amino acids, on early Earth McCollom and Seewald, ; Proskurowski et al.
Vents of this type may have been common on early Earth if oceanic crust was richer in olivine e. Many simple organic compounds can be obtained with high yields in redox reactions catalyzed by iron, which was present in prebiotic, non-oxidizing oceans in much higher concentrations than in present-day oceans Derry and Jacobsen, and might have served as a redox catalyst on prebiotic Earth Cairns-Smith, Ammonia, as a source of nitrogen for prebiotic synthesis of amino acids and amines, is readily synthesized by iron-catalyzed reduction of inorganic nitrites in simulated prebiotic ocean conditions Summers and Chang, Amino acids and other simple carboxylic acids can also be synthesized in iron-catalyzed redox reactions Schoonen et al.
Various methods of prebiotic amino acid synthesis have been described Pascal et al. One of the oldest known methods of amino acid synthesis, the Strecker synthesis Fig. Although currently known catalysts are not likely to have been available under prebiotic conditions, it is not impossible that some other types of chiral catalysts would have been used in the Strecker syntheses on primordial Earth. Amino acid synthesis in the Strecker reaction. However, recent studies show that, in the case of short side chain natural amino acids, the reaction does not proceed beyond the stage of di- and tripeptides Eliash et al.
A readily available source of carbohydrate derivatives on prebiotic Earth was reactions in the atmosphere that resulted mainly in formaldehyde formation. This simplest aldehyde can be formed under a variety of conditions, including UV irradiation of the primordial atmosphere composed of H 2 O, CO 2 , and H 2 Pinto et al. Various other aldehydes and sugars can be synthesized by condensation of formaldehyde Weber, or by direct synthesis pathways similar to those of formaldehyde formation. Formaldehyde is also a substrate in the formose-type reactions—the sugar polymerization—which has been proposed as a historically first prebiotic route to obtain various mixtures of sugars Breslow, ; Fig.
Example of a prebiotic sugar synthesis: elements of the formose reaction system. It has been shown that amines as amino acid derivatives or free primary amines also can effectively catalyze sugar backbone formation Weber, Long-chain carboxylic acids can be synthesized in Fisher-Tropsch-type syntheses, producing aliphatic chains and carbonyl groups in the inorganic gas condensations catalyzed on the mineral beds McCollom et al.
Several methods of prebiotic synthesis of heterocyclic nucleobases, pyrimidines, and purines are known Pavey et al. All four nucleobases can be synthesized from formamide, in the reaction catalyzed by various inorganic mineral catalysts Saladino et al. Cyanoacetaldehyde condensation, catalyzed by guanidine hydrochloride, is a possible pathway to pyrimidines, and starting from thiourea, a thiopyrimidine product can be obtained Robertson et al.
Hydrogen cyanide condensation in the presence of ammonia yields purines and purine derivatives Lowe et al. Phosphorus was probably introduced into prebiotic synthesis at an early stage of prebiotic evolution Macia et al. Phosphorus can be obtained from various inorganic sources Brown and Kornberg, For example, phosphonic acid, synthesized from sodium phosphite Fig. In fact, extraterrestrial delivery of the phosphide mineral schreibersite may have introduced a highly reactive form of phosphorus into prebiotic chemistry Pasek et al.
Phosphonic acid synthesis based on inorganic sources of phosphorous; pathway proved by the existence of vinyl phosphonic acid in the Murchison meteorite De Graaf et al. A separate branch of prebiotic chemistry research is focused on the problem of polymerization of previously synthesized building blocks. Various studies have shown that amino acids can randomly polymerize to peptides Plankensteiner et al. The exact mechanism and conditions of such polymerizations are now the subject of extensive study. All major organic functional groups can therefore be synthesized prebiotically; there are known reactions that can lead to the formation of amines, carboxylic acids, aldehydes and ketones, and heterocycles.
All key components of the metabolic reactions can be synthesized, in various pathways leading to the amino acids, carbohydrates, lipids, and nucleobases. Also, inorganic sources of phosphorus and sulfur can be used to introduce these atoms to the organic compounds Fig. Examples of prebiotic syntheses of major organic molecules.
Red: nucleic acid building blocks; blue: peptide building block; green: membrane building blocks. Faustus: That Damned Woman sees the grandiose protagonist rewritten as a woman trading sacrifices to travel across centuries and alter the fabric of history. The legend of Doctor Faustus follows the twists and turns in the demise of a scholar who — growing bored of traditional studies — sells their soul to the devil in exchange for the powers of black magic. Drawing together the famous interpretations of the Faustus myth by Marlowe and Goethe as well as a wide range of other re-imaginings, the play asks grand questions about sacrifice and legacy.
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Half a century later, this family, like millions of others, has re-discovered what it means to be Jewish in the first half of the 20th century. Based on the hit film, Pretty Women is a modern Cinderella story. A businessman hires an escort to spend the weekend with him, but before long, the two learn that their connection goes beyond a simple transaction.
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Grammy award-winning Nmon Ford plays Orfeus. This epic tale of humanity versus leadership centres on a young woman with the courage to defend her beliefs — whatever the cost. Ava is a twenty-something Londoner. Following the death of her estranged father, she journeys to Iran in search of his past and her extended family.
Exploring the rich culture and thriving art scene of this oft misunderstood country, Ava is swept into a world of raves, raids and illicit love, all whilst negotiating family politics, Tehran traffic and the morality police. Based on real-life testimonials, this new play by Nadia Fall offers a tender and witty snapshot of modern life in Iran.
The huge-hearted, smash-hit musical arrives at the magnificent London Coliseum from next April for a strictly limited week season. A leading British doctor with a radical plan to save the NHS and a Silicon Valley billionaire with a radical plan to halt climate change, meet outside an abandoned train on a salt flat in South America. For Kimsa and his daughter who live there, the arrival of these strangers initially seems like an opportunity.
Things are tense. People are on the edge. The Third Intifada is right around the corner. But on a contested piece of land near their village of Beit al-Qadir, this couple is about to go dogging. A lecturer in Chile. A study group in the USA. A torture instructor in Argentina. A hangman in Mexico. An asylum. A woman locked in a windowless cell, with no memory as to who she is, or how she arrived there.
When spiritualist medium Mrs Lyall requires a new assistant, this nameless woman seems the perfect candidate. The story concerns a character called George, a fictionalised version of the artist, who immerses himself in the painting. Leon and Troy are best mates trying to figure out their place in the world amid mounting unemployment and simmering racial tensions. Ambitious Texan oil executive Mac MacIntyre arrives in Scotland on a mission to buy a small seaside village and replace it with a refinery.
Before the locals get rich, they must decide what their home is worth. Following a triumphant sold-out season, Joseph and the Amazing Technicolor Dreamcoat will return to The London Palladium for a strictly limited season of just 77 performances in summer Released as a concept album in , the stage version of Joseph and the Amazing Technicolor Dreamcoat has become one of the worlds most beloved family musicals. The multi-award-winning show, which began life as a small scale school concert, has been performed hundreds of thousands of times including multiple runs in the West End and on Broadway, international number one tours, and productions in over 80 countries as far afield as Austria and Zimbabwe and from Israel to Peru.
Cush Jumbo makes her Young Vic debut as a new kind of Hamlet for this generation.
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A smash-hit at Chichester Festival Theatre and in the West End, this irresistibly charming show returns to London in to make a summer splash! When a letter arrives from the mother they thought was dead, twins Racine and Anaia travel from the Dirty South to the California desert and a yellow house with teal shutters. They are on a mission to avenge her past and ready to take down anyone who stands in their way. This is a personal response to the Nanjing Massacre, otherwise known as the Rape of Nanking. In an explosive time for political discourse around the world, Nanjing asks: what does it mean to fight hatred and love one another?
It comes to the Royal Court as part of a tour of the seven countries which make up its story. We all want to meet people from history. The trouble is everyone is dead! Will you conquered by King William? Will you sink or swim with King Henry I? Will Thomas Becket get the chop? Are you scared to scale the Tudor scaffold?
Join the gorgeous Georgians as they take over England! Break into Buckingham Palace and hide from the Queen! Watch out for the witch of World War Two! Free-spirit carnival barker Billy Bigelow's love for the curiously soulful Julie Jordan persists beyond the circles of time. Calling all brave heroes! Enter into a magical world of myths and legends in this fantastical new interactive show for all the family. Unveil a myriad of dark secrets and come face to face with some of the most magnificent monsters and terrifying beasts ever to walk the earth.
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