These Are Titan's Highest Mountains -- What Lies Beneath?
Should humankind establish a presence throughout the solar system, future rock climbers and mountaineers might want to put Titan on their list of exploration destinations.
Should humankind establish a presence throughout the solar system, future rock climbers and mountaineers might want to put Titan on their list of exploration destinations. Scientists have used precision Cassini observations to measure the heights of the hazy moon's biggest mountains - and they're surprisingly high.
Using the NASA spacecraft's radar, planetary scientists were able to cut through the opaque atmosphere, revealing a rich bounty of geological features, including the moon's highest peak.
"It's not only the highest point we've found so far on Titan, but we think it's the highest point we're likely to find," said Stephen Wall, deputy lead of the Cassini radar team at NASA's Jet Propulsion Laboratory in Pasadena, Calif., at the 47th annual Lunar and Planetary Science Conference at The Woodlands, Texas, on Wednesday.
This highest peak comes in at 3,337 meters (or 10,948 feet) and was discovered nestled within 3 mountain ranges known as Mithrim Montes. All of Titan's highest peaks are around 3,000 meters (10,000 feet) in elevation and clustered around the moon's equator.
As a comparison, the highest peak on Earth is Mount Everest at 8,848 meters (29,029 feet), so "Titan Mons" certainly isn't gunning for the record of largest mountain in the solar system. But considering Titan is two and a half times smaller than Earth, having a mountain two and a half times times smaller than the highest mountain on Earth still seems impressive.
(Of course, even Earth doesn't have the highest mountain in the solar system, that record goes to Mars' extinct volcano Olympus Mons at a height of 22,000 meters, and it is even dwarfed by a couple of peaks on Venus.)
This radar study was intended to seek out tectonically active regions in Titan's crust. On Earth, mountains form through tectonic movements (in regions along subduction zones, for example) and through volcanic activity - both sure signs of active geology. Over time, erosion processes wear down mountains and cliffs, providing clues as to their age.
"As explorers, we're motivated to find the highest or deepest places, partly because it's exciting. But Titan's extremes also tell us important things about forces affecting its evolution," said Jani Radebaugh, a Cassini radar team associate at Brigham Young University in Provo, Utah, and research leader.
Studying Titan's mountains also reveals exciting clues as to what lies beneath. Titan, like many small bodies throughout the solar system, appears to have a sub-surface ocean of liquid water that acts like the molten mantle on which Earth's crust floats. However, the bedrock on Titan is likely far softer than rock on Earth, a factor that would limit the height of the moon's mountain ranges.
"There is lot of value in examining the topography of Titan in a broad, global sense, since it tells us about forces acting on the surface from below as well as above," said Radebaugh.
Now the researchers hope to further study these mysterious mountain ranges to figure out how they were formed. Are powerful tides from Saturn squeezing the moon's interior, producing the upthrust to form mountains? Or is there another process at play?
Titan is often cited as a "young Earth analog" - in other words, planetary scientists study the moon, in part, to understand how our planet may have looked before life was sparked on its surface. Although much further away from the sun, Titan possesses many atmospheric processes we have here on Earth, including a methane cycle that produces precipitation (rain), which creates river channels, pooling as vast methane/ethane lakes and "seas." Other weather processes, including surface winds and fog, have been detected.
Add this amazing soup of atmospheric processes with the fact that Titan's surface is rich in prebiotic chemicals (the building blocks of life as we know it) and you have what could be viewed as a miniature, albeit colder, Earth bustling with the potential for life.
Although trekking up Titan's mountains would likely be quite the feat (the 14 percent Earth gravity will help the climb, but the cold toxic atmosphere will ensure you stay sealed inside your spacesuit), understanding their formation and evolution will add yet another chapter to Titan's early-Earth similarities, not only revealing what mysteries lie beneath the crust, but also the processes that may optimize the moon for life.
The trio of ridges on Titan known as Mithrim Montes is home to the hazy Saturnian moon's tallest peak.
Ten years ago,
and became the first ever robotic mission to touch down on a world in the outer solar system. During its daring 2 hour, 27 minute descent through the murky atmosphere of Saturn's largest moon, the probe revealed an unprecedented view of of the alien environment. On landing, Huygens survived on the hydrocarbon-rich surface for only 72 minutes before its batteries drained, but the data it transmitted via NASA's Cassini spacecraft was nothing short of revolutionary -- data that continues to be analyzed 10 years after that fateful day on Jan. 14, 2005.
Here are just a few mind-blowing images from Huygens as it gave us our first intimate look at the solar system's only moon known to possess a thick atmosphere and vast liquid methane-ethane lakes -- a world that, like Jupiter's moon Europa, invokes exciting hypotheses of extraterrestrial biology.
After traveling with the Cassini mission for seven years during its interplanetary transit from Earth to Saturn orbit, the command was given for Huygens to detach from its mothership. For 21 days, the small disk-like probe was by itself, cruising toward Titan. As Huygens ripped through Titan's atmosphere, eventually slowing down enough for its heatshield to drop away and parachutes deploy, the probe got to work, rapidly photographing its descent and collecting atmospheric data. On Wednesday, The European Space Agency released the full series of
, showing how the moon's dune-covered surface slowly came to view as Huygens slowly drifted to the surface below.
Looking down, Huygens also captured a slowly evolving view of its eventual landing spot. Shown here, a fish-eye view of the landscape below starts to detail some of the surface features the probe would be soon analyzing up-close. In the run-up to landing day, mission scientists were unsure whether Huygens would land on a solid surface or splash down in a methane/ethane puddle or lake. As it turned out, the probe "splatted down" in Titan's alien mud -- a mix of small grains of ice.
Photographs during descent gradually showed an alien, yet familiar, landscape. Titan is covered in dunes, valleys and lakes -- all shaped by erosion processes we'd find on Earth. The valleys are cut by liquid action and the thick atmosphere produces winds and weather systems that form dune fields of fine hydrocarbon sand. But these Titan weather systems are not driven by an Earth-like water cycle. As the atmosphere is too cold to support water in a liquid state, other chemicals, such as methane and ethane exist as a liquid, forming their own cycle. Methane rain is now known to fall onto the landscape, creating rivers that erode valleys and form deltas in vast liquid methane-ethane lakes.
By landing a probe onto Titan's surface, the joint NASA/ESA Cassini-Huygens mission was able to get "ground proof" of flyby imaging and radar. Last year, Cassini completed its 100th Titan flyby, so in the 10 years since Huygens landed, planetary scientists have been getting a front row seat of the moon. But in 2005, Titan science was as foggy as the moon's atmosphere, so by overlaying ground-based observations with Cassini images, a better interpretation of landscape features spotted by Cassini could be made.
Although low-resolution and grainy, the first images of the landscape surrounding Huygens after it landed at 13:34 CET (12:34 GMT) on Jan. 14, 2005, stunned the world. Rounded stones appeared to litter the grains of hydrocarbon sand and ice. The eroded rocks immediately reminded us of eroded pebbles -- rocks that have undergone liquid action for long periods of time. The landing zone resembled a dried-up lake bed and surrounding that area, evidence for rapid, transient flows of liquid could be seen.
The Huygens lander, in its short solo mission, punched well above its weight, opening our eyes to an alien world within our solar system that is littered with prebiotic chemicals, a world that resembles a young Earth, beckoning our inquiring minds to return some day.