The storms closed in again, but by the time they cleared once more, Rizzo had completed the image-amplifier for me. Now, with the tiny telescope I had, I could see almost as far as a professional instrument would allow. I could even lie comfortably in my bunk, watch the amplifier's viewscreen, and control the entire set-up remotely. Then it happened. At first it was simply a curiosity. An oddity. * * * * * I happened to be studying a Cepheid variable star--one of the huge, very bright stars that pulsate so regularly that you can set your watch by them. It had attracted my attention because it seemed to be unusually close for a Cepheid--only 700 lightyears away. The distance could be easily gauged by timing the star's pulsations.[1] [Footnote 1: _Astronomers have been able, since about 1910, to estimate the distances of Cepheid variable stars by timing their pulsations. The length of this type of star's pulsation is a true measure of its intrinsic brightness. Comparing the star's actual brightness to its apparent brightness, as seen from Earth, gives a good value for the star's distance._] I talked Rizzo into helping me set up a spectrometer. We scavenged shamelessly from the dome's spare parts bin and finally produced an instrument that would break up the light of the star into its component wavelengths, and thereby tell us much about the star's chemical composition and surface temperature. At first I didn't believe what I saw. The star's spectrum--a broad rainbow of colors--was criss-crossed with narrow dark lines. That was all right. They're called absorption lines; the Sun has thousands of them in its spectrum. But one line--_one_--was an insolently bright emission line. All the laws of physics and chemistry said it couldn't be there. But it was. We photographed the star dozens of times. We checked our instruments ceaselessly. I spent hours scanning the star's "official" spectrum in the microspool reader. The bright emission line was not on the catalogue spectrum. There was nothing wrong with our instruments. Yet the bright line showed up. It was real. "I don't understand it," I admitted. "I've seen stars with bright emission spectra before, but a single bright line in an absorption spectrum! It's unheard-of. One single wavelength ... one particular type of atom at one precise energy-level ... why? Why is it emitting energy when the other wavelengths aren't?" Rizzo was sitting on his bunk, puffing a cigaret. He blew a cloud of smoke at the low ceiling. "Maybe it's one of those laser signals you were telling me about a couple weeks ago." I scowled at him. "Come on, now. I'm serious. This thing has me puzzled." "Now wait a minute ... you're the one who said radio astronomers were straining their ears for nothing. You're the one who said we ought to be looking. So look!" He was enjoying his revenge. I shook my head, and turned back to the meteorological equipment.