The image showed six exposures of the ring, together with streaked trails of background stars. Smith reported that the thickness of the ring was less than 30 kilometers, and that it extended to a point 128 000 kilometers from the center of Jupiter, or 57 000 kilometers above the clouds. In response to this discovery, scientists were eagerly planning to alter the Voyager 2 encounter sequence to try to obtain additional information on the ring. The newspapers carried stories of the ring discovery on Thursday, March 8. One story was seen by two University of Hawaii astronomers, Eric Becklin and Gareth Wynn-Williams, who were observing at Mauna Kea Observatory, at an altitude of 4200 meters on the Big Island of Hawaii. Within two days they had succeeded in detecting the rings by their reflected sunlight, at an infrared wavelength of 2.2 micrometers, providing a rapid confirmation of the Voyager discovery. As the plasma measurements from the Io flyby were analyzed, an additional clue to the origin of sulfur and oxygen was revealed. Herb Bridge reported the detection of sulfur dioxide (SO₂), the simplest molecule composed of these two atoms. The high-resolution tape-recorded pictures of Io baffled imaging scientists. A number of features looked like volcanic flows; together with the absence of impact craters, these features indicated a geologically active planet. A central point of discussion was the recent theoretical work on Io by Stanton Peale of the University of California and two NASA scientists, Pat Cassen and Ray Reynolds. These authors had just published a paper in the March 2 issue of _Science_ showing how tidal heating from Jupiter’s gravity could melt the interior of Io. They wrote that “widespread and recurrent surface volcanism might occur.” It began to look as if the prediction had been correct. Thursday, March 8.