Science Pics of the Week: Dark gas mountain spied on Neptune
Neptune at blue wavelengths of light (467 nm), from May 16, 2016. Credit: NASA, ESA, and M.H. Wong and J. Tollefson (UC Berkeley)
Friday, June 24, 2016, 6:34 PM - Hubble spies a new dark 'gas mountain' on Neptune, NASA records waves of fire during space experiment, and pics of Pluto hint at a subsurface liquid ocean!
A new dark spot on Neptune
Given its distance and lack of any orbiting spacecraft, we don't often hear about Neptune in the news, but the Hubble Space Telescope is pushing the ice giant into the spotlight with a new image.
Taken on May 16, 2016, astronomers aimed Hubble at Neptune to confirm sightings made by amateur and professional astronomers here on Earth, starting back in July of 2015, which appeared to show a new patch of bright clouds in the planet's southern hemisphere.
As these clouds are often associated with Neptune's dark spots, anticyclonic "storms" that are similar to Jupiter's Great Red Spot, but smaller and shorter-lived, and which show up best at blue wavelengths of light, Hubble was needed to get the clearest image (shown above).
The dark spot shows up quite well in blue light here, in the lower middle part of Neptune's disk. It comes in even better when all wavelengths are combined, so that we can also see the bright clouds accompanying it.
Credit: NASA, ESA, and M.H. Wong and J. Tollefson (UC Berkeley)
Why is this being referred to as a mountain? Mike Wong, a research astronomer from University of California at Berkeley who led the Hubble team, explains:
"Dark vortices coast through the atmosphere like huge, lens-shaped gaseous mountains, and the companion clouds are similar to so-called orographic clouds that appear as pancake-shaped features lingering over mountains on Earth."
Read more at www.nasa.gov.
Special note: why is the image so blurry when Hubble can take incredibly detailed images of distant galaxies and nebula? It all comes down to size and brightness. Those distant galaxies and nebulae are immense and give off a proportional amount of light for Hubble to gather. Neptune, by comparison, is small and rather dim, and thus Hubble can only pick out so much. Still, the space telescope offers us some of the best imagery of the planet.
Watching fires burn in space is mesmerizing
We've seen astronauts ignite little floating drops of fuel, to produce glowing jellyfish flames, but NASA's Spacecraft Fire Experiment (Saffire-I) has given us a whole new look at how flames spread in the microgravity environment.
The total burn time shown above was roughly 8 minutes, as the flames slowly advanced across the test material.
According to NASA:
The Saffire-I experiment enclosure was approximately half a meter wide by 1 meter deep by 1.3 meter long and consisted of a flow duct and avionics bay. Inside the flow duct, the cotton-fiberglass blend burn sample measured 0.4 m wide by 1 meter long. When commanded by Orbital ATK and Saffire ground controllers operating from Dulles, Virginia, it was ignited by a hot wire. Previous to this experiment, the largest fire experiment that had been conducted in space is about the size of an index card.
This test, the first of three, will help researchers design effective ways of fighting fires in space, to keep astronauts safe for long-duration missions.
Read more, along with a full timeline of the experiment and added images, here.
Cracks in Pluto's facade hint at a sub-surface ocean
Scientists examining the various images still being sent back by NASA's New Horizons spacecraft, after its July 2015 Pluto flyby, are discovering some pretty amazing things about the dwarf planet.
The latest revelation? Pluto may have an ocean of liquid water locked away under its frozen surface.
The researchers, from Brown University in Providence, RI, and the Planetary Science Institute in Tucson, AZ, have examined imagery showing long, deep fissures on Pluto's surface, which indicate that the dwarf planet underwent some kind of expansion in its past.
Pluto's surface features, as taken by New Horizons prior to its July 14, 2015 flyby. Credit: NASA/JHUAPL/SwRI
Based on what's known about how these icy worlds form, if Pluto's subsurface environment had completely frozen through, it would have caused the surface to contract, and for Pluto to shrink. While it's true that water ice expands as it forms, thus filling a larger volume than the original water, ice that forms at very cold temperatures and under high pressure - as you'd find inside Pluto and other large icy bodies of the solar system - comes out as "ice II" (normal water ice is "ice I"). Due to ice II's very ordered structure, it freezes with a higher density, and thus lower volume than the original water.
"We don’t see the things on the surface we’d expect if there had been a global contraction," study lead author Noah Hammond, a graduate student at Brown University, told News at Brown. "So we conclude that ice II has not formed, and therefore that the ocean hasn’t completely frozen."
How could an ocean of liquid water still exist that far out from the Sun? The model used by Hammond and his team determined that Pluto's crust is somewhere around 300 kilometres thick. That alone would offer some insulation, but according to Hammond, the presence of nitrogen and methane ices would allow Pluto to retain even more of its interior heat.
Read more at Brown University.
Watch Below: Hubble see the Universe expanding faster than expected