night
Middletown produced another chart that showed the connection with the
Sun in a way that was even more convincing.

LATHAM. How was that?

NIEMAND. I said that the lines drawn down through the days of greatest
mental disturbance slanted slightly. On this second chart the squares
were dated under one another not at intervals of twenty-seven days, but
at intervals of twenty-seven point three days.

LATHAM. Why is that so important?

NIEMAND. Because the average period of solar rotation in the sunspot
zone is not twenty-seven days but twenty-seven point three days. And on
this chart the lines did not slant but went vertically downward. The
correlation with the synodic rotation of the Sun was practically
perfect.

LATHAM. But how did you get onto the S-Regions?

NIEMAND. Middletown was immediately struck by the resemblance between
the chart of mental disturbance and one he had been plotting over the
years from his radio observations. Now when he compared the two charts
the resemblance between the two was unmistakable. The pattern shown by
the chart of mental disturbance corresponded in a striking way with the
solar chart but with this difference. The disturbances on the Earth
started two days later on the average than the disturbances due to the
S-Regions on the Sun. In other words, there was a lag of about
forty-eight hours between the two. But otherwise they were almost
identical.

LATHAM. But if these S-Regions of Middletown's are invisible how could
he detect them?

NIEMAND. The S-Regions are invisible to the eye through an _optical_
telescope, but are detected with ease by a _radio_ telescope. Middletown
had discovered them when he was a graduate student working on radio
astronomy in Australia, and he had followed up his researches with the
more powerful equipment at Turtle Back Mountain. The formation of an
S-Region is heralded by a long series of bursts of a few seconds
duration, when the radiation may increase up to several thousand times
that of the background intensity. These noise storms have been recorded
simultaneously on wavelengths of from one to fifteen meters, which so
far is the upper limit of the observations. In a few instances, however,
intense bursts have also been detected down to fifty cm.

LATHAM. I believe you said the periods of mental disturbance last for
about ten or twelve days. How does that tie-in with the S-Regions?

NIEMAND. Very closely. You see it takes about twelve day