Read The Year Without Summer for Free Online Page A

supposed
     to envelope [sic] the opake [sic] and solid body of the sun.” Even those who supported
     this concept found it difficult to imagine how any gap within a liquid could remain
     unfilled; one contributor to the Gentleman’s Magazine in Britain likened it to “no less a miracle than the passage of the Israelites through
     the Red Sea.” Perhaps, suggested a writer in the Baltimore American , “the Sun has cast forth several immense bodies, and … there is a danger of one of
     them coming in contact with our little tiney [sic] globe, when, in the horrible crash,
     we may experience another deluge, or suffer a terrible conflagration!”
    No one in 1816 understood that sunspots are formed by variations in the strength of
     the magnetic field that surrounds the sun. Occasionally, a portion of the magnetic
     field grows strong enough that the field coils back on itself and punctures the surface
     of the sun, a process which inhibits the fusion reactions that produce solar energy.
     This in turn reduces the temperature of the sun’s surface at the point of the puncture.
     Since the brightness of the sun’s surface is proportional to its temperature, the
     sunspots appear darker than the rest of the sun.
    Scientists in Europe and the United States had regularly recorded sunspot activity
     with telescopes since the early seventeenth century, when several astronomers, including
     Galileo, first observed them. Most of the earliest sunspot observations were taken
     during the period now known as the Maunder Minimum—named for the English scientist
     Edward Maunder—that extended from 1645–1717, when sunspot activity was at an unusually
     low level. The near disappearance of sunspots in the 1650s puzzled astronomers, as
     did their sudden reemergence in the second decade of the eighteenth century.
    While individual sunspots occur almost randomly, the total number of spots follows
     a fairly predictable eleven-year cycle (a cycle that was discovered in 1844). But
     sunspot activity also varies over much longer periods of time which are less predictable
     and less regular than the short-term cycle. The eruption of Tambora coincided with
     another minimum in sunspot activity—the Dalton Minimum of 1790–1830. The Dalton Minimum
     was shorter and less intense than the Maunder Minimum, but it still resulted in a
     notable decrease in sunspot activity; hence the surprise exhibited by the appearance
     of a large sunspot in April 1816.
    According to one contemporary account, no sunspots of this magnitude had been witnessed
     in the United States since 1779. Moreover, observers could stare at the spot without
     the usual protection of shaded glasses, because the atmosphere lately had been filled
     with a curious thick haze—“a fine dust,” reported a Virginia newspaper, “very injurious
     to respiration.” “It had nothing of the nature of a humid fog,” noted an American
     physician. “It was like that smoking vapour which overspread Europe about thirty years
     ago.” And while sunspots typically are visible to the naked eye only when the sun
     is barely above the horizon, when the atmosphere has scattered much of the sunlight,
     this spot could be seen throughout much of the day. In fact, the aerosol haze from
     Tambora may have lengthened by as much as five times the usual window for viewing
     sunspots after sunrise and before sunset.
    Since most Americans had never witnessed the sunspots that routinely move across the
     face of the sun, this highly visible spot—much larger than usual—generated more apprehension
     than the haze. Some feared it was an omen of impending apocalypse, a “calamitous sign
     in heaven,” or a warning that “the sun may, in time … become wholly incrusted” with
     spots, “so as to plunge us at once into the unutterable darkness that characterized
     the primitive chaos.” Others predicted the huge spot would weaken the sun’s rays and
     permanently cool Earth’s