Robert W. Noyes

The author describes the formation of the Sun with its "run-of-the-mill" qualities, and its "quiet" face, then introduces the theatrics of magnetic activity -- sunspots, prominences, flares, the hot corona, solar wind.

Why do the tails of comets always always point away from the Sun? (Coronal solar wind! [198]).

As humankind wrestles with the so-called "energy crisis" we may be comforted by the steady and predictable availability of the Sun's output. We have always tapped this energy, and it lies at the heart of fossil fuels (decayed remains of earlier generations), wind energy (from the heating of the atmosphere), and even hydro-electric sources (water raised to high elevations by evaporation). But for practical purposes, the fossil fuels are nonrenewable--they required millions of years to store and can only be replenished at similar time-scales. Once consumed, gone in a flash. The short-lived fossil fuel era will only last a few centuries. [232]

The day of reckoning for fossil fuel depletion can be staved off by using nuclear fission reactors. However, the fuel for these reactors is uranium-235, which can be mined from the earth's crust. Fission is the splitting of atoms when struck by a neutron. Uranium-235 is the only naturally occurring fissionable isotope of uranium. The process is accompanied by a host of issues, none of which have been resolved: disposal, storage and transport of waste, radioactivity spewing accidents (including earthquakes and tsunamis), misuse and sabotage. Like fossil fuels, uranium-235 is nonrenewable, with a much more limited supply. While "breeder" reactors and fusion devices may prolong the era, it remains a limited resource.

The author thoroughly establishes the fact that solar energy is the sole source of energy with truly attractive features. It can be "mined" safely, and "burned" without increasing "acid rain" or the "greenhouse" effect. The drawbacks -- an unevenly distributed dilute form of energy--are safely and easily addressed. To produce solar energy equal to present US consumption would require less than 0.5 percent of the US land mass devoted to that purpose. This is less than the total area of the US which is covered with paved highways. While substantial--18,000 square miles or 1/6 of the area of the State of Arizona--it is not depleting.

As for the Sun, it will continue to shine for the next 5 billion years. Flares will probably become less violent. In the future, the luminosity of the Sun will be increasing in the next billion years. By the time the Sun is 10 billion years old, its radius will also be increased, and at the apex of its career as a red giant, its diameter will be 100 times its present size, and the surface of the Earth will be about 1700 degrees Kelvin, a waterless sea of molten lava. [255] To maintain our present temperature ranges, humankind will have to be relocating outward approximately 1.8 A.U., roughly between the orbits of Mars and Jupiter.… (more)