The large white ovals are about forty years old. Dr. Smith explained how they formed: Between 1939 and 1940, “where those three white spots exist right now, was a rather bright band similar to the north temperate zone we see on Jupiter right now. In that time period of a year or so, three darkish spots formed. A dark cloud spread out at each one of those three locations and just kept spreading longitudinally until the white material condensed between them.” In the end, everything was dark except for the three ovals, which have persisted ever since. Torrence Johnson of the Imaging Team commented on a photo of Io in which features resembling circular crater-type structures seemed to be visible. “Whatever they are, [those circular features] are approaching the size of the things that we would call basins if they were impact structures on other planets. We don’t really know whether they’re impact structures. They have some characteristics that look reminiscent of impact structures. They could be endogenic—volcanic in origin—or internally generated in some other way.” Johnson also showed another photograph of Io, this one taken against black sky, showing a “strikingly different face” looking, perhaps, like someone’s nightmare, glaring back at the intruder from Earth. One huge feature—a “bullseye” or “hoof print” on Io—appeared to be approximately 1000 kilometers long. No one had ever seen such a feature, and the imaging scientists could only speculate about its significance. [Illustration: Small-scale structures in the jet streams of Jupiter’s north tropical zone reveal details of atmospheric circulation. The small dark oval near the right edge of the zone may offer a glimpse deep into Jupiter’s atmosphere. Between the regularly spaced dark ovals near the bottom of the frame are more small-scale features that are being studied for their roles in Jovian atmospheric activity. The blue-gray regions along the shear line between the equatorial zone and the north equatorial belt also appear to be windows into the deeper regions of the atmosphere. This photo was taken February 19 by Voyager 1 from a distance of 14 million kilometers. [P-21160C]] A few days earlier, someone had posted in the Imaging Team area a quote from a 1975 review paper on the Jovian satellites by David Morrison and Joseph Burns. The section on Io began, “Io is one of the most intriguing objects in the solar system.” This statement seemed more and more appropriate as Voyager images improved. Johnson referred to this day as equivalent to the “late 1960s” in our study of the Jovian satellites. “We can see much more clearly than ever before, but still not clearly enough to provide understanding of what we are seeing.” Sunday, March 4.