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Testing Gravity. Before re-entering Falcon for the final time, Scott unexpectedly demonstrated his scientific —and theatrical—expertise. Holding a hammer in his right hand and a feather from the Air Force Academy's pet falcon Hungry in his left, Scott said, "I guess one of the reasons we got here today was because of a gentleman named Galileo, who a long time ago made a rather significant discovery about falling objects in gravity fields."
Scott was referring to Galileo's assertion that objects in the same field fall at the same rate of acceleration regardless of their weight. Only air resistance, Galileo told the skeptics of his day, caused a lighter object like a feather to descend more slowly. Because there is no lunar atmosphere, Scott had decided the moon would be a perfect stage for a Galilean gravity demonstration. It was. Feather and hammer hit the surface simultaneously, and Scott jubilantly said, "How about that? This proves that Mr. Galileo was correct."
After Scott and Irwin climbed back aboard Falcon, TV watchers on earth were treated to their first view of a lunar launch. Unlike the huge Saturn rocket, which lifts ponderously and, at first, almost imperceptibly from the pad, Falcon suddenly shot up like a jack-in-the-box. Left behind was the lander's lower stage, its gold insulation foil shredding and scattering in the engine's blast. Almost simultaneously, the tape-recorded strains of the Air Force song, Off
We Go into the Wild Blue Yonder, came from Falcon's radio. "Hey," said Scott, "a good smooth ride."
Busy Pilot. High overhead in Endeavour, Al Worden was making good use of his time. During his three lonely days of solo orbiting, he was busier than any previous command module pilot, working through a taxing schedule of scientific experiments. Worden's first important finding was his observation of relatively young volcanically formed cones at the edge of the Sea of Serenity. According to NASA scientists, this is the best evidence yet that the moon may have been volcanically active as recently as a billion years ago. Until now, many scientists thought that the moon's eruptions had ceased much earlier in its history.
The $10 million package of instruments crammed into an equipment bay of Endeavour's service module provided equally spectacular findings. A mass spectrometer detected an eruption of carbon dioxide gas and traces of hydrocarbons on the moon's far side. Such emissions could be a sign of continued volcanism (although scientists cautioned that they might have come from Endeavour itself). Working in conjunction with a laser altimeter, X-ray and gamma-ray spectrometers radioed evidence of the moon's chemical composition. Readings showed greater concentrations of aluminum in the lunar highlands than in the moon's maria. In addition, sensors detected a curious radioactive "hot spot" in the Sea of Storms.