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Cosmic sponge. NASA
released this image of Saturn's icy moon Hyperion today to
oohs and aahs. Snapped by the Cassini spacecraft on 26
September, it reveals a uniquely spongy appearance of the
185-kilometer-long moon that mission team members are
tentatively attributing to the erosional powers of "dirt". The
dark material visible at the bottom of the densely packed
impact craters seems to have absorbed extra solar heat that
ate into the underlying ice, deepening normally saucer-shaped
craters into honeycombs. (Photo: JPL/NASA)
Petite propulsion.
For insects that zip across the surface of water, even a
smooth pond isn't entirely flat. Along the shore, surface
tension creates a steep mountain of liquid from their
perspective. To make the jump,
water gliders and others deform the surface into a dimple with
their legs, researchers report 29 September in Nature.
By letting their front legs dip into the water, capillary
action generates enough force to pull them right up to the top
of the slope without moving a limb. (Photo: Lucy Mendel,
David Hu, and John Bush)
Shipshape. The
Mary Rose, a warship that served Henry VIII's navy for
35 years before sinking in 1545, is facing a new enemy. Soft
clay on the ocean floor preserved the relic until it was
raised in 1982, but now sulfur compounds are oxidizing to
sulfuric acid in the ship's timbers, according to a report
published online 26 September in the Proceedings of the
National Academy of Sciences. Researchers are currently
testing ways to halt the process, for example by removing iron
compounds that catalyze the acid formation. (Photo: Mary
Rose Trust)
Still smokin'.
Volcanologists celebrated the first anniversary of the ongoing
dome-building eruption of Mount St. Helens 23 September as the
mountain continued to ooze a pickup truck's worth of hot rock
every second. Geochemical analyses now suggest that some of
the emerging rock solidified from magma freshly squeezed from
a great depth, not just from leftovers of the early 1980s
eruptions. That reinforces researchers' expectations that the
current eruption could go on for years or even decades.
(Photo: John Ewert and Jim Vallance, USGS)
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