Friday, March 4, 2016

Science from Above and Below

Science brought to the news discoveries and observations from above and below.

From Above
Pluto's Cthulhu

One of Pluto’s most identifiable features, Cthulhu (pronounced kuh-THU-lu) stretches nearly halfway around Pluto’s equator, starting from the west of the great nitrogen ice plains known as Sputnik Planum. Measuring approximately 1,850 miles (3,000 kilometers) long and 450 miles (750 kilometers) wide, Cthulhu is a bit larger than the state of Alaska.

Cthulhu’s appearance is characterized by a dark surface, which scientists think is due to being covered by a layer of dark tholins – complex molecules that form when methane is exposed to sunlight. Cthulhu’s geology exhibits a wide variety of landscapes—from mountainous to smooth, and to heavily cratered and fractured.

The reddish enhanced color image shown as the left inset reveals a mountain range located in southeast Cthulhu that’s 260 miles (420 kilometers) long. The range is situated among craters, with narrow valleys separating its peaks. The upper slopes of the highest peaks are coated with a bright material that contrasts sharply with the dark red color of the surrounding plains.

Scientists think this bright material could be predominantly methane that has condensed as ice onto the peaks from Pluto's atmosphere. "That this material coats only the upper slopes of the peaks suggests methane ice may act like water in Earth's atmosphere, condensing as frost at high altitude," said John Stansberry, a New Horizons science team member from Space Telescope Science Institute, Baltimore, Maryland. Compositional data from the Ralph/Multispectral Visible Imaging Camera (MVIC) on NASA’s New Horizons spacecraft, shown in the right inset, indicates that the location of the bright ice on the mountain peaks correlates almost exactly with the distribution of methane ice, shown in false color as purple.

Deep rumbles, unearthly moans, high pitched screeching: these are but a few elements of the alien soundscape researchers have now recorded for the first time at Challenger Deep, the deepest known valley on the seafloor.

One might expect Challenger Deep—which sits at the bottom of the Mariana trench some 36,000 feet beneath the ocean surface—to be a quiet place. But in reality, we know very little about what life is like down there: as with most places where the sun never shines, the Mariana trench is shrouded in mystery.

“Light does not propagate underwater very far,” oceanographer Bob Dziak of the National Oceanic and Atmospheric Administration (NOAA) told Gizmodo. “But sound waves travel long distances through the Earth’s oceans. Acoustics is really the best way to get a good picture of deep ocean environments.”

From Below
36,000 feet below sea level

From Gizmodo
The propellor from a ship passing above makes quite a ruckus at Challenger Deep

Dziak would know. He’s the guy who led the recent effort to capture audio recordings from Challenger Deep. First, Dizak and his team had to design and build an instrument that could withstand the crushing 16,000 pounds-per-square-inch worth of pressure felt seven miles beneath the surface. Next, they developed a mooring system that would lower their audio gear—a titanium-encased hydrophone—at a slow, controlled speed, so that it could acclimate to the dramatic pressure buildup during its journey.

And after successfully planting a hydrophone in Challenger Deep, and making recordings for 23 straight days, Dziak’s team had to wait until November for the weather and ship traffic to clear so they could haul it back up. It was a major effort, but now, we’ve got the first soundbites from the deepest spot on the Earth’s surface to show for it.

They’re as haunting and otherworldly as you might imagine.

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