Infrasound, also known as low-frequency sound, describes sound waves with a frequency below the lower limit of human audibility. It cost $196billion over 40 years, ended the lives of 14 astronauts and managed to make less than half the flights promised. The pits also are the perfect size for cell storage, according to Thanga. On the moon, pits in the ground lead to lava tubes, now hollow, that reach down some 8o to 100 meters underground, making them ideal for protecting precious cargo from the lunar elements. But I think the same complexity is what makes them beautiful, he said.
infrasound is smaller than 2000000 miles.
( z0 have-degree :ARG1 ( z1 sound ) :ARG2 ( z2 small ) :ARG3 ( z3 more ) :ARG4 ( z4 distance-quantity :quant 2000000 :unit ( z5 mile ) ) )
(z0 / have-degree-91
    :ARG1 (z1 / sound-01)
    :ARG2 (z2 / small)
    :ARG3 (z3 / more)
    :ARG4 (z4 / distance-quantity
              :quant 2000000
              :unit (z5 / mile)))
infrasound is smaller than 2000000 miles .
z0 :ARG1 z1
z0 :ARG2 z2
z0 :ARG3 z3
z4 :quant 0
z0 :ARG4 z4
z4 :unit z5