Gamma-ray bursts

Gamma-ray bursts (GRBs) are bright flashes of gamma rays coming from the cosmos. They occur roughly once per day, typically last for tens of seconds, and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this Review, we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglow.     

The costs of the soviet empire

A comprehensive framework is developed and applied to estimate the economic costs incurred by the Soviet Union in acquiring, maintaining, and expanding its empire. The terms "empire" and "costs" are explicitly defined. Between 1971 and 1980, the average ratio between empire costs and Soviet gross national product was about 3.5 percent; as a ratio to Soviet military spending, empire costs averaged about 28 percent. The burden imposed on Soviet economic growth by empire costs is also considered, as well as rates of change in these costs, and the important political, military, and strategic benefits associated by the Soviet leadership with maintenance and expansion of the empire. Prospective empire costs and changes in Soviet economic constraints resulting from the declining performance of the domestic economy are also considered.     

Technology assessment, soviet style

The Soviet Union is actively considering two plans to divert large northern lakes and rivers to the south of the country. If adopted, these would rank among the most expensive and complicated engineering projects ever undertaken, with unforeseeable but possibly far-reaching environmental effects. The plans, now at an advanced stage, have aroused a spirited public controversy, providing an unusual glimpse of Soviet policy-making and technology assessment. Major decisions are due by 1985. The question is, what will happen to the quality and openness of this debate as the political stakes rise and the time of decision draws near?