Here, I consider our current view of the universe. I start with the Hubble Ultra-Deep Field, which shows about 10,000 galaxies in a tiny field of view. The whole of the observable universe contains over two trillion galaxies. I discuss two important principles regarding the nature of the universe and our place within it. The cosmological principle holds that the universe is homogeneous provided that we make comparisons at a high enough level of spatial scale. The Copernican principle maintains that our position within the universe is not central. We are certainly not central in the solar system or the galaxy; whether we are central in the universe is a tougher question to grapple with. We are at the centre of our own observable universe, but by definition any other observer is at the centre of theirs. We then turn from seeing galaxies in general to seeing individual events. These include long-known phenomena such as the Crab Nebula, which was produced by a supernova explosion. They also include more recently observed events such as collisions of neutron stars. We end by looking at the relative power of radio signals produced by biological and non-biological sources.

Carbon-based life is the most probable, and hence the most common, form of life in the Milky Way, and indeed in the universe. However, it may not be the only form of life. We should keep an open mind on this; the King Carbon hypothesis should not give way to carbon chauvinism.

Chapter 2 discusses the structure of gaseous protoplanetary disks. It begins by explaining how observations can be used to infer disk mass, disk structure, and stellar accretion rate. The vertical structure of a gas disk in hydrostatic equilibrium is derived, and the considerations that determine the surface density and temperature profile of a passive disk are described. The concept of the condensation sequence is outlined, along with the ionization and recombination processes that determine the ionization state. Physical processes that can produce large-scale structure in disks - zonal flows, vortices, and ice lines - are discussed.

Chapter 4 covers the evolution of the solid component of protoplanetary disks, from dust through to the formation of km-scale planetesimals. The physics of how dust particles interact with the gas through aerodynamic drag is described, together with the consequences - vertical settling, radial drift, particle trapping, and particle pile-up. The outcome of particle collisions, and their theoretical description using the coagulation equation, are reviewed. Collective mechanisms for planetesimal formation via gravitational collapse are discussed, starting with the classical Goldreich-Ward theory, and concluding with the streaming instability of aerodynamically coupled mixtures of gas and dust.

Chapter 6 describes theoretical models for the formation of giant planets, and relevant observational constraints from the Solar System. The core accretion theory for giant planet formation is introduced, including the equations describing planetary envelope structure, the concept of a critical core mass, and illustrative evolutionary tracks for giant planet growth. Current knowledge of the internal structure of Jupiter, based on measurements of the gravitational field, is summarized. The conditions under which a massive gas disk becomes unstable and fragments are described, together with the likely outcome of disk instability.

Chapter 5 focuses on the formation of rocky planetary-scale bodies, including terrestrial planets, super-Earths, and giant planet cores. The concepts of gravitational focusing, shear and dispersion dominated encounters, and catastrophic disruption are introduced. A simple "particle in a box" statistical model for planetary growth is described, along with the ideas of orderly, runaway, and oligarchic growth. Factors that determine the planetesimal velocity dispersion, including viscous stirring, dynamical friction, and gas drag, are discussed. The regimes of pebble accretion, the conditions under which it operates, and the pebble accretion rate, are discussed. The standard model for the final assembly of the Solar System's terrestrial planets is outlined.

Chapter 7 covers processes that lead to the evolution of planetary systems. Planetary migration in gaseous disks is described, starting with an elementary derivation of the torque in the impulse approximation and continuing with a discussion of the physics of Lindblad and co-rotation torques. Type I and Type 2 planetary migration, gap opening, and eccentricity evolution are described. The regimes of secular and resonant dynamics are defined, together with an intuitive physical description of mean-motion resonance. Resonant capture, Kozai-Lidov dynamics, and planetesimal disk migration are discussed. The concept of Hill stability is introduced and derived, and the outcome of planetary system instability leading to planet-planet scattering is reviewed. The Nice model and the Grand Tack model for the early evolution of the Solar System are discussed. The size distribution resulting from a steady-state collisional cascade is derived, and stellar and white dwarf debris disk evolution described.

Chapter 3 introduces physical processes that lead to the evolution of gaseous protoplanetary disks. It begins with a derivation of the equation describing the evolution of a thin viscous accretion disk, a discussion of solutions, and introduction of the Shakura-Sunyaev alpha prescription. Hydrodynamic sources of angular momentum transport, including self-gravity, the vertical shear instability, and vortices, are discussed. Magnetohydrodynamic (MHD) sources of angular momentum transport are reviewed, starting with the magnetorotational instability in ideal MHD. The non-ideal induction equation of MHD is derived, and the importance of Ohmic diffusion, ambipolar diffusion, and the Hall effect for protoplanetary disks is reviewed. A simple model for angular momentum loss due to a magnetized disk wind is discussed. The chapter concludes with a description of disk dispersal via photoevaporation, and magnetospheric star-disk interaction.

Chapter 1 introduces key observational constraints for the theory of planet formation. It reviews the properties of the Solar System's planets and minor bodies, explains the principle of radioactive dating of primitive meteorites, and defines the minimum mass Solar Nebula. The main methods used to detect extrasolar planets - radial velocity monitoring, transits, direct imaging, microlensing, and astrometry - are introduced and compared. Observed properties of extrasolar planetary systems are reviewed, including the orbital distribution of planets, their mass-radius relation, and the dependence of planet frequency on stellar host properties. The concept of the habitable zone and the factors that influence planetary habitability are described.

Multi- and hyperspectral sensors in the visible to short-wave infrared (0.4–2.5 μm) are sensitive to spectral features caused by electronic charge transfer and transition metal crystal field band as well as molecular overtone absorptions. This chapter reviews several processing techniques used to map materials on planetary surfaces based on their reflectance spectra in this spectral region. Techniques that are reviewed include spectral matching in the form of spectral angle and spectral information divergence, linear and nonlinear spectral unmixing, partial unmixing/matched filters, and machine learning approaches in the form of self-organizing maps, neural network classification, and support vector machines.