Tiny presolar grains include C polymorphs, carbides, nitrides, oxides, silicates, metallic Fe-Ni, and organic compounds. Rare CAIs and AOAs contain refractory oxides and silicates. Major phases in type-3 OC include olivine and low-Ca pyroxene with variable FeO/(FeO+MgO), metallic Fe-Ni, troilite, and nearly exclusively within chondrules, crystallites of Ca-pyroxene, rare pigeonite, and tiny grains of merrillite. Whole-rock thermal metamorphism produced secondary phases: orthopyroxene, diopside, chromite, ilmenite, rutile, phosphate, and plagioclase. Diffusion facilitated by metamorphism causes increasing compositional homogeneity in olivine and pyroxene. Some minerals and mineraloids are formed at high shock pressure. These include lingunite and maskelynite from plagioclase; ahrensite, asimowite, poirierite, ringwoodite, and wadsleyite from olivine; akimotoite, bridgmanite, hemleyite, hiroseite, and majorite from orthopyroxene; chenmingite and xieite from chromite; tuite from merrillite; wangdaodeite from ilmenite; and TiO2-II from rutile. Parent-body aqueous alteration produced phyllosilicates, Ni-rich sulfides, Ni-rich metal phases, carbides, oxides, and small calcite crystals.

While most sustainability transitions researchers agree on the need for cross-disciplinary collaboration, such collaborations can be difficult in practice. Scholars often disagree on (a) how to understand the world (ontology) and (b) what constitutes important knowledge about transitions (epistemology). From this observation, this chapter explores ontological and epistemological debates in sustainability transitions research. It begins by outlining dominant frameworks, particularly the multi-level perspective (MLP), and their foundational assumptions drawn from evolutionary economics and science and technology studies (STS). The chapter identifies two main criticisms of the MLP: the need for an expanded epistemic focus and ontological critiques from proponents of ‘flat ontologies’ and critical realists. It then discusses new epistemological approaches that challenge the dominant narrative that transitions primarily emerge through innovation journeys. These criticisms focus on capitalism, coloniality, and justice, highlighting how mainstream transition studies tend to externalise such concerns. The chapter concludes by supporting radical theoretical pluralism as key to understanding sustainability transitions’ increasing complexities.

The first asteroid, Ceres, was discovered on the first night of the nineteenth century. There are now more than 800,000 numbered asteroids. Numerous properties link most meteorite groups to asteroids. These include cooling rates, the presence in some specimens of solar-wind gas, formation ages and CRE ages, orbital parameters, and the retrieval of chondritic material from asteroids visited by spacecraft. In addition, the spectral reflectance properties of meteorites match those of particular asteroids. Space-weathering can account for differences between OC spectra and those of S-complex and Q-complex asteroids. Ordinary-chondrite parent asteroids probably initially had an onion-shell-like structure due to internal heating by 26Al. These bodies were likely collisionally disrupted and gravitationally reassembled while still hot.

Chondrule types include porphyritic (FeO-poor and FeO-rich), barred olivine, radial pyroxene, granular, and cryptocrystalline. Chondrules in unequilibrated OC tend to have unfractionated refractory lithophile abundances; metallic components include one enriched in refractory siderophiles and one in common and volatile siderophiles. Although most chondrules are a few hundred µm in diameter, microchondrules (0.8-40 µm) and macrochondrules (0.5–5 cm) also occur. Compound chondrules include enveloping, sibling, and adhering varieties. Some chondrules have fine-grained rims, others igneous rims. Relict grains survived the most recent chondrule melting. Calcium–aluminum-rich inclusions (CAIs) and amoeboid olivine aggregates (AOAs) are very rare. Matrix material occurs mainly as chondrule rims and isolated lumps. Carbon-rich aggregates and clasts contain poorly graphitized C, amorphous C, metallic Fe-Ni, and minor chromite. A few H chondrites contain halite. Opaque assemblages include metallic Fe-Ni, sulfide, and oxides. Some shocked OC contain metallic Cu. Large metal nodules formed by impact-induced vaporization and fractional condensation. Many shocked OC exhibit silicate darkening, and many are breccias with a variety of clasts. Some OC are regolith breccias enriched in solar-wind-implanted noble gases.

Social practice theories have become increasingly prominent in sustainability transitions research. By drawing attention to everyday life and social dynamics as key issues in sustainability transitions alongside technologies, infrastructures, and policies, practice theories provide valuable contributions to transition research, governance, and intervention design. Instead of focusing solely on individual behaviours or structures, they view practices - collective patterns of human activity - as the central unit of analysis, emerging from and at the same time shaping (infra)structures and behaviours. Therefore, practice theories can be fruitfully utilised as an alternative or complementary perspective on sustainability transition frameworks to identify, explain and address the social dynamics of change. In this chapter, we show how social practice theories can be used to study - as well as to bring about - innovations and disruptions for sustainability transitions. We start by providing a concise overview of what practices are and how they change. We also showcase an example of a practice theory-inspired change initiative as well as discuss the main differences, similarities, and synergies of social practice theories and the multi-level perspective of socio-technical transitions. We end with outlining some of the on-going debates and further research needs.

The principal methods used in experimental and observational science typically involve hypothesis testing, follow-ups on serendipitous discoveries, the use of new analytical tools (instrumental, numerical, or statistical) to examine extant samples or data sets, the acquisition of new samples to analyze, and the formulation of theoretical models. Many studies, including those in meteoritics and cosmochemistry, employ several of these methods.

The Deep Transitions framework expands sustainability transitions research by analysing the long-term co-evolution of multiple socio-technical systems. It argues that current system configurations drive both environmental crises and social inequalities. Unlike traditional transition studies, which focus on single systems, Deep Transitions links historical trajectories - such as the Industrial Revolution - to the First Deep Transition, marked by fossil-fuel reliance, mass production, and unchecked resource use. The framework integrates sustainability transitions theory with longwave economic cycles, emphasizing shared meta-rules in shaping industrial modernity. Empirical applications include historical analyses of mass production, international governance, and wars as landscape shocks. The envisioned Second Deep Transition aims to reconfigure socio-technical systems towards planetary sustainability and social equity. Future research should refine the framework through empirical testing, engagement with socio-ecological systems, and governance innovations. Deep Transitions challenges conventional approaches by highlighting systemic inertia, global inequalities, and the need for a just transition.

Ordinary-chondrite petrologic types range from unheated type-3.00 to highly recrystallized type-6 samples. During metamorphism, olivine grains in ferroan chondrules become depleted in Cr2O3 as Cr2O3 variability decreases. Matrix olivine grains become more ferroan and bulk matrix loses C, metal, and sulfide. Metamorphism induces whole-rock loss of some H2O, C, noble gases, and volatile mobile elements. Type-6 OC contain homogeneous mafic silicates. The maximum metamorphic temperatures in OC ranged from ~200-260ºC for type 3.00 to ~820-930ºC for type 6. Asteroids were heated mainly by 26Al early in Solar System history and by collisions afterwards. Some OC were annealed after shock. Shock also caused microstructural mineral dislocations. Brecciation and melting can occur during collisions. Indigenous water may be mobilized during heating, leading to aqueous alteration of matrix material and chondrule glass. Carbide-magnetite assemblages and fayalite-silica associations are produced during alteration. Some asteroids of OC composition were melted – IVA iron meteorites were derived from the metal core of one such differentiated asteroid.

This chapter discusses the role of visions, expectations, and socio-technical imaginaries in shaping sustainability transitions. Imagining futures different from current socio-technical regimes is essential for legitimizing and mobilizing niche technologies and driving system change. More recently, mission-oriented and transformative innovation policies have emphasised envisioning and collective expectations in defining and implementing long-term goals. The chapter introduces the historical development of these concepts within sustainability transition studies, including transition management, strategic niche management, and technological innovation systems. It presents and compares various anticipatory practices and techniques for exploring and shaping transition dynamics. ‘Futuring methods’ such as scenario development, technology foresight, roadmapping, and modelling are not just neutral tools but shape political problems and solutions. The chapter concludes by illustrating the influence of visions, expectations, and imaginaries in the historical evolution of hydrogen futures and highlighting key research trends.

Orbits have been calculated for dozens of meteorite falls; they match those of many Near-Earth Asteroids. The Kirkwood Gaps are hiatuses in histograms of asteroid semi-major axes; few asteroids occur in these gaps. The gaps are caused by repeated gravitational tugs by Jupiter on asteroids with orbital periods that are simple fractions of Jupiter’s orbital period. Among the most efficient mechanisms for delivering asteroids to the Earth is the υ6 resonance associated with Saturn. The resonance occurs when there is a simple numerical ratio between the precession frequency of an asteroid’s longitude of perihelion and that of the mean precession frequency of Saturn’s longitude of perihelion.

Sustainability transitions involve complex, long-term societal changes shaped by diverse actors within dynamic structural contexts. This chapter takes a role based perspective, distinguishing between social roles, which evolve with societal values and priorities, and transition roles, which reflect actors’ engagement with transition dynamics. It explores conceptual and empirical applications, highlighting research trends and gaps. Social roles provide insights into institutional change over time, while transition roles reveal how actors strategically position themselves within transitions. Emphasizing the fluid and negotiated nature of roles, the chapter concludes by advocating for longitudinal studies on social roles and the use of transition roles as a boundary object for action-oriented, transdisciplinary sustainability research.

Sustainability transitions have often been described as involving ‘disruptions’. However, many writings in this field have been imprecise about what disruption means in the context of transitions, beyond the disruption of the status quo. References to disruptions in the literature have ranged from a discourse on disruptive niche innovations to disruptive landscape influences. A systematic literature review revealed that the conceptualisation of disruption was often imprecise and empirical studies were largely focused on the energy sector. In this chapter, we build on this definition of disruption and complement the understanding by reviewing the most recent literature, adding to the initial review. This chapter provides much-needed clarity on the conceptual confusion that has emerged and evaluates the links between the concept of disruption and the ways in which mainstream technologies, practices, and business models in socio-technical regimes need to be phased out, destabilised, or undergo decline. We conclude by examining the relevance of the concept of disruption to emerging scholarly and societal debates on just transitions.

OC parent bodies accreted from a mix of chondrules, chondrule fragments, grains of metallic Fe-Ni and sulfide, porous aggregates of fine-grained dust, and rare CAIs, AOAs, and tiny presolar grains. After accretion, the OC asteroids underwent thermal metamorphism, mainly due to the decay of 26Al. They initially developed onion-shell structures but suffered disruption and reassembly while still hot. Subsequent collisions produced a variety of breccias on each body. The L parent asteroid was destroyed by a catastrophic collision ~470 Ma ago.