Back to the Moon with Nuclear Rockets

Tidal bore, with suloys atop, spreading into Spencer Gulf, taken by the Shuttle Endeavor,at 170 nautical miles altitude. Note the city of Adelaide at the head c fthe estuaryon the east side of the Gulf of St. Vincent. The white line crossing the /o ver rightof the image was a contrail from a commercial jet aircraft.none in the Alboran Sea. Was this the result of the turbulencefrom the Gibraltar solitons? Or does the Alboran Sea havesome other dynamic action that precludes the formation ofspiral eddies; that is, were we to learn the generating forcesof the spirals in the first place?Throughout the next 12 years, there was no certain answerto those questions. We finally concluded that the solitons movingthrough the Alboran Sea were too energetic to permit theformation of spiral eddies. Beginning with the flight of ShuttleEndeavor in May 1996, that conclusion was shown to be erroneousby a series of outstanding photographs of the easternhalf of the Alboran Sea. From just west of the longitude ofCabo de los Muertos, spiral eddies, intricately interwoven,were observed cascading into the western Mediterranean, orvice versa (see photo, p. 40). To the west, to the approaches tothe Strait of Gibraltar, none but the large-scale turbulence ofsolitons seems present.Suloys: The Strangest Waves of AllFor centuries, seamen have described lines of unusual andchaotic waves that extend across the ocean's surface. Sometimescurved, in other cases straight or in irregular "globby"bands, the state of the sea is of furious, precipitous, steep waves.The first published descriptions of chaotic wave-lines wereby Matthew Fontaine Maury in his 1857 edition of The PhysicalGeography of the Ocean. Maury gleaned the informationfrom the thousands of ship logs available to him in the archivesof the U.S. Naval Observatory. In every case, the state of thesea was so unusual in the experience of the ship's master, thatthe log entries were in great detail.Such chaotic waves were encounteredin every sea and ocean and inevery season, and although the waveheights, widths, and lengths of thezones differed (some extended fromhorizon to horizon), the common denominatorswere winds of speeds lessthan 1 5 knots, and a rather mild sea.There was usually an intense hissing,roaring sound from the wave line, audiblefrom distances of several kilometers.Of course, those were thedays of sailing ships, with little extraneoussounds to mask that of thewaves. Even so, some witnesses havecompared the sound with that of apassing train, or the sounds from busyAbbey Road in London.During mild, moonlit nights, conditionsmay permit wave lines to beeasily observed. Such was the experienceof Dr. Paul Scully-Power inthe Tasman Sea while cruisingthrough a dead calm in May 1975,aboard HMAS Kimbla. On the bridgeat 0100 hours, he was startled by abroad, moonlit band of white ruffledwater, stretching across the ship'scourse as far as he could see in eitherdirection. On his request, theship was stcjpped immediately in the middle of the choppywater.The Kimb a has a length of 50 meters; the wave-line's widthwas less tha i the ship's length. Paul quickly set about launchingexpend; ble bathythermograph probes (XBTs), one afteranother. He managed to obtain 20 measurements of temperatureto deptl is of 200 meters before the ship drifted out of thewave line.At first git nee, the continuous temperature traces appearedto indicate ciaotic temperature inversions, ranging from 0.4°Cthrough dep hs of a few centimeters, to those of 2°C+, extendingthrough tens of meters. When the depths of the major inversionswe e plotted against time, however, it was clear thatthe tempera ures defined a cluster of internal waves, less than50 meters v ide and extending to the greatest depths of theprobes: 200 meters!No furthe measurements were possible because of the demandingcruise schedule. (In addition, both the captain andScully-Powc ' rather lost interest when they decided that the interminablyong line of white ruffled water was not a dumpfrom a Swan Lager tanker.) Nonetheless, the data taken thatnight in the Tasman Sea make up the only definitive set takenwithin a cha Dtic wave line.Of more tian casual interest in this regard is a 1983 Japanesereport o "a mysterious underwater acoustic effect" associatedwith " iomes" and distinct from conventional surfacewaves. As a chaotic wave line is approached, one would expectan inte isification of ambient noise over that from surfacewaves. Afte all, the chaotic wave action is far greater withinthan outsid !—great enough to "bang and thump the hull to21stCENTL RY Summer 1999 41