There is a long and celebrated history of skepticism about political parties in the United States, stretching back to George Washington’s farewell address in which he warned against partisan factions and, of course, to Madison’s Republic, in which majority factions are equated with tyranny. The skepticism of people like Madison and Washington at the founding is echoed by contemporary critics who lament current manifestations of partisanship in national politics ranging from partisan attacks (and defenses) of Supreme Court nominees, to obviously biased information spread by presidential spokespeople (and leaders of the opposing party to the current administration, of whichever party), to the antics on display at national nominating conventions or campaign rallies. Many close observers of American politics worry about the effects of partisan polarization on gerrymandering, policymaking, gridlock, and extremism.

Compared with stars, the region between them, called the interstellar medium or “ISM,” is very low density; but it is not a completely empty vacuum. A key theme in this chapter is that stars are themselves formed out of this ISM material through gravitational contraction, making for a star–gas–star cycle. We explore the characteristics of cold and warm regions of the ISM and their roles in star formation.

We now consider why stars shine with such extreme brightness. Over the long-term (i.e., millions of years), the enormous energy emitted comes from the energy generated (by nuclear fusion) in the stellar core, as discussed further in Chapter 18. But the more immediate reason stars shine is more direct, namely because their surfaces are so very hot. We explore the key physical laws governing such thermal radiation and how it depends on temperature.

This chapter explores what is known as the Cosmic Microwave Background (CMB), what it is, how it was discovered and our recent efforts to measure and map it. In general, the analysis finds remarkably good overall agreement with predictions of the now-standard “lambda CDM” model of a universe, in which there is both cold dark matter (CDM) to spur structure formation, as well as dark-energy acceleration that is well-represented by a cosmological constant, lambda. From this we can infer 13.8 Gyr for the age of the universe.

The timescale analyses in Chapter 8 show that nuclear fusion provides a long-lasting energy source that we can associate with main-sequence stars in the H–R diagram. This chapter addresses the following questions: What are the requirements for H to He fusion to occur in the stellar core? And how is this to be related to the luminosity versus surface temperature scaling for main-sequence stars? In particular, how might this determine the relation between mass and radius? What does it imply about the lower mass limit for stars to undergo hydrogen fusion?

We walk through the different epochs and eras of the universe, going forward in time from the Hot Big Bang. In the earliest universe, radiation (photons) dominated over matter. As the universe cools, electrons are able to recombine with protons, then helium and other light elements were formed in the first few minutes. Cosmic inflation is posited to overcome several problems, but investigations to probe and perhaps confirm inflation are ongoing.

This chapter gives a brief overview of observational astronomy, using optical instruments and other wavelengths. We present a general formula for the increase in the limiting magnitude resulting from an increased telescope aperture. For light of particular wavelength, the diffraction from a telescope with a specific diameter sets a fundamental limit to the smallest possible angular separation that can be resolved.

Observations of binary systems indicate that main sequence stars follow an empirical mass–luminosity relation L ~ M 3. The physical basis for this can be understood by considering the two basic relations of stellar structure, namely hydrostatic equilibrium and radiative diffusion. In practice, the transport of energy from the stellar interior toward the surface sometimes occurs through convection instead of radiative diffusion; this has important consequence for stellar structure and thus for the scaling of luminosity.

Imagine a person who readily admits he’s not much interested in politics, often doesn’t vote, and isn’t well informed about candidates and their policy stands. To make this discussion more concrete and personal, let’s call this individual Brian. It is obvious that Brian does not meet the expectation of a self-interested citizen actively pursuing his interests through political participation. If Brian is typical of many citizens, the foundations of Madison’s theory of representative government would seem to be jeopardy.

The dawn of the third millennium saw prophets of doom foretelling the end of civilization. Central to this climate of fear was the willful destruction of the environment and, more precisely, the harm caused by climate change. In the Caribbean, such fears were confirmed by rising temperatures, the increased intensity of extreme weather events, the devastation of coral reefs, species extinctions, the virulence of viral diseases, and rising sea levels. Globally, nineteen of the hottest years ever recorded occurred in the first twenty years of the twenty-first century. The oceans were at their warmest in 2019, and global greenhouse gas emissions hit a record high. These alarming indicators of environmental deterioration had far-reaching ramifications in politics, economy, and society. Indeed, the challenges faced by the Caribbean in the first twenty years of the twenty-first century occurred in the context of a changing global geopolitical climate that affected most aspects of life, from health and material welfare to identity, sovereignty, and culture. For the Caribbean, the home of the hurricane, a perfect storm was brewing.