Blog Archives
Floes of Frozen Methane May Be Floating on Titan’s Lakes
Artist’s rendering of an ice-covered lake surface on Titan (NASA/JPL-Caltech/USGS)
Although surface temperatures on Titan are cold enough that methane can exist as a liquid, filling lakes and flowing in streams, it may sometimes get so cold that even the liquid methane and ethane freezes, forming floes and icebergs of frozen hydrocarbons. This Titanic revelation was announced today during the 221st American Astronomical Society meeting in Long Beach, CA.
Hidden Ice Found on Mercury!
MESSENGER image of Mercury
Who says Mercury’s too hot to be really cool? Even three times closer to the Sun than we are, lacking atmosphere and with scorching daytime temperatures of 425 ºC (800 ºF), Mercury still has places more than cold enough to hide ice. This is the most recent announcement from the MESSENGER mission team: (very nearly) confirmed ice on the first rock from the Sun!
Dione in Color
Although made mostly of ice and rock, Saturn’s moon Dione (pronounced DEE-oh-nee) does have some color to it — although mostly chilly hues of steel blue, as seen in this color-composite made from raw images acquired by Cassini on July 23.
Ancient Ice Found in a Frigid Lunar Crater
Laser altimeter data from NASA’s LRO spacecraft shows water ice in a lunar crater’s surface material
NASA’s Lunar Reconnaissance Orbiter has found water ice lining a deep crater located on the Moon’s south pole — as much as 22% of the surface material of the crater appears to be composed of ice, NASA and university scientists report.
Evidence of Lakes Beneath Europa’s Ice
Chaos terrain on Europa suggests subsurface lakes. (NASA/JPL/Ted Stryk)
New research on Jupiter’s ice-covered moon Europa indicates the presence of a subsurface lake buried beneath frozen mounds of huge jumbled chunks of ice. While it has long been believed that Europa’s ice lies atop a deep underground ocean, these new findings support the possibility of large pockets of liquid water being much closer to the moon’s surface — as well as energy from the Sun — and ultimately boosting the possibility that Europa could harbor life.
“Now we see evidence that it’s a thick ice shell that can mix vigorously, and new evidence for giant shallow lakes. That could make Europa and its ocean more habitable.”
– Britney Schmidt, Institute for Geophysics, University of Texas at Austin
A Fan of Shadows
Clumped material in Saturn's F ring casts a spread of linear shadows
Cassini captured this visible-light image on October 16, 2010, showing a thick clump of icy material in Saturn’s bright F ring casting a “fan” of thin shadows. Clumps like this have been seen many times before and may be caused by the gravitational effects of passing shepherd moons like Prometheus or as-of-yet undiscovered moonlets within the ropy rings themselves.
Click here to see how the 63-mile-wide Prometheus can pull streamers of the F ring away as it dips in and out along the course of its scalloped orbit.
Positioned just outside the extreme outer edge of Saturn’s A ring system, the F ring is made up of very bright particles of ice loosely organized into ropy strands and transient clumps. It ranges anywhere from 20 to 300 miles wide.
Image: NASA / JPL / Space Science Institute
Icy Spiders
Araneiform features on Mars
Near Mars’ polar regions, spidery cracks and crevasses in the surface hold the last remnants of the winter season’s carbon dioxide frost – a.k.a. “dry ice” – which will eventually evaporate into the Martian atmosphere as CO2 gas. This process is seen on Earth only in specialized manmade situations such as when used as frozen packing material or special fog effects for a spooky setting…it’s simply too warm on Earth for carbon dioxide ice to exist naturally in any large quantity. But in Mars’ chilly climate CO2 is a major player in the natural erosion processes on the surface as it settles in layers during the winter months and then sublimates – sometimes rather forcefully! – from underlying surface layers as the climate warms in spring and summer.
The polar terrain seen here has been broken open by these processes, creating radiating cracks that resemble giant spiders or spiderwebs…hence the use of the term “araneiform” terrain when describing these areas.
Once all the dry ice has evaporated the channels will be much less visible to spacecraft like the Mars Reconnaissance Orbiter which captured this image using its HiRISE imager. They will become the same color of the surrounding landscape, waiting for the Mars winter to set in to fill them back in with a blanket of CO2 ice.
Click the image to read more on the HiRISE site.
Image credit: NASA / JPL / University of Arizona
