a fracture where the mare surface
“opened” like a cooling joint. “But
since the scientists have studied
the pictures,” Irwin wrote, “the most
popular theory is that Hadley Rille
was probably a lava tube that collapsed.”
All around the two men were
enormous slabs of basalt and the geologists in the back room in Houston
quickly began pressing for them to
move further downslope, though Joe
Allen was becoming nervous. Looking at televised pictures, it seemed to
him as though they were right on the
edge of a precipice.
In fact, the rille had no dramatic
“drop”; rather, it resembled the gentle shoulder of a hill, and t