Tag Archives: Titan

Radar Probes Titan’s Seas and Magic Islands

The Cassini Space Probe has measured the depth of a 40-kilometer-long stretch of Kraken Mare, the largest sea on Saturn’s moon Titan.

Shortly before capturing the first images showing Titan’s hydrocarbon seas with sunlight bouncing off of them, Cassini used radar to measure a strip of Kraken’s eastern side. Depths varied from 20 to 35 meters, but NASA cautions that these may be far from the deepest parts of the sea. 

The area studied during the August flyby is near the mouth of what on Earth would be considered a flooded river valley. Even though Titan’s rivers and seas are filled with hydrocarbons, probably methane and ethane rather than water, it is thought the processes of erosion and flooding are similar.

The study was part of a 200 kilometer sweep across the breadth of Kraken, but for the majority of this the results came back blank. NASA concluded that, “For the areas in which Cassini did not observe a radar echo from the seafloor, Kraken Mare might be too deep for the radar beam to penetrate.” An alternative possibility is that the still unknown make up of Titan’s seas varies, and the blank stretches represent more absorbent liquids.

The land around parts of the Kraken sea is quite steep, and if this continues beneath the surface, some sections might be deep enough to host the mythical beasts after which it is named.

At the same time, two bright features were seen in Kraken Mare that had not been visible on previous flybys. These may be related to the mysterious feature dubbed “magic island” that was spotted with a radar in Ligeia Mare last July before disappearing again a few days later. 

This time, however, both the Cassini radar and Visible and Infrared Mapping Spectrometer (VIMS) were focused on the right location, bolstering the opportunity to identify what causes these bright spots. Patches of waves or some form of debris are currently the favored explanations, with some alternatives such as fog or submarine icebergs having been ruled out.

The findings were presented to a workshop at the Planetary Sciences Division of the American Astronomical Society.

In January, NASA plans to do another radar sweep of Punga Mare, the smallest of the three bodies large enough to be designated seas. The same pass will provide an opportunity for researchers to study Ligeia for further clues as to the nature of these intermittent bright spots. This will be the last attempt to study Titan’s seas and sea floors before Cassini makes its final dive into Saturn to collect as much data as it can on the atmosphere of our solar system’s second largest planet before being crushed to oblivion.

H/T Space.com

Read more: http://www.iflscience.com/space/radar-probes-titans-seas-and-magic-islands

What Is This Mysterious Feature On Titan?

Saturns moon Titan continues to be one of the most fascinating places in the Solar System. Alongside its Earth-like weather system and possible underground ocean, it is the only place other than Earth known to have bodies of liquid on the surface. And in one of its seas, a mysterious feature is puzzling scientists.

This feature, dubbed the magic island,was spotted in images from 2013 and 2014 taken by the Cassini spacecraft. It appears near the coast of Titans second-largest body of liquid, Ligeia Mare, and measures about 260 square kilometers (100 square miles) in size roughly the size of Washington, DC. The lake itself is 130,000 square kilometers (50,000 square miles).

But mysteriously, the feature is not present in radar images takenin 2007 nor, most recently, on January 11, 2015 in an image released by NASA yesterday. This suggests that Titans seas, composed of liquid hydrocarbons such as methane, are active.

Now we have confirmation that these seas are not stagnant ponds just sitting there, but there is activity in them, said Jason Hofgartner of NASAs Jet Propulsion Laboratory, reported New Scientist.

The feature is seen here in 2013 and 2014, but not in other years.NASA/JPL-Caltech/ASI/Cornell

Perhaps most baffling of all, though, is that we dont know what is causing the feature. The predominant theory at the moment is that it is waves moving slowly on the surface of Titan. It has already been theorized that tiny waves, less than a meter tall, might be moving on Titans seas at a sedate one meter per second. This feature could be the first direct evidence for such waves.

Other theories abound, though. The feature could be the result of bubbles rising up from the depths of Ligeia Mare, which is up to 170 meters (560 feet) deep in places. It could also be some sort of solid material dislodged from the bottom of the sea, temporarily rising up before sinking down again.

The waves theory is supported by the fact that the moons Northern Hemisphere, where the sea is located, is entering its summer, with Titans year lasting 30 Earth years. Winds are expected to pick up during the summer, possibly giving rise to waves like this.

In April 2017, Cassini will make its next and final observation of its region, before it is sent plunging into Saturns atmosphere later that year. Scientists will be eagerly awaiting more images to see if this feature has returned.

Photo Gallery

Read more: http://www.iflscience.com/space/mysterious-magic-island-titan-disappears-latest-cassini-image

Titan’s Sunsets Give Insight To Hazy Atmospheres of Exoplanets

Certain characteristics of exoplanets can be difficult to study due to their atmospheres obscuring details. NASA scientists have begun to Saturn’s moon Titan at sunset, in the hope that it will help them to understand the haze from the atmosphere and what it could reveal about surface conditions. The study was led by Tyler Robinson of NASA’s Ames Research Center and the paper was published in the Proceedings of the National Academy of Sciences.

An atmosphere can act like a prism, separating light that passes through it into a spectrum of its components. The result of this spectrum provides information about the planetary body’s atmospheric composition, temperature, and structure, giving clues about its habitability. For exoplanets, this information is obtained as it transits its parent star. The light that goes through the atmosphere isn’t much different, but different enough to obtain meaningful information.

Titan’s atmosphere produces a haze just like an exoplanet, and it is strongest at sunset. The Cassini orbiter, which has been studying Saturn up close since 2004, has also gathered a considerable amount of information about Titan. By comparing information about Titan from when it produces the heaviest amount of haze versus when the haze is not as strong, scientists will be able to clarify findings and refine techniques used on exoplanets.

“Previously, it was unclear exactly how hazes were affecting observations of transiting exoplanets,” Robinson said in a press release. “So we turned to Titan, a hazy world in our own solar system that has been extensively studied by Cassini.”

The heavy haze created by Titan, and presumably many exoplanets as well, may overcomplicate some of the spectral information collected by researchers. However, many models currently used by astronomers tend to err on the side of being overly simplified due to constraints of computing power. For this study, the researchers analyzed four instances of Titan’s haze, using Cassini’s visual and infrared mapping spectrometer instrument. 

They found that the haze makes it very difficult to collect information about anything beyond the uppermost layer of the atmosphere. Titan’s lack of gravity (when compared to Earth) allows its atmosphere to extend out about 600 km (370 miles) around it. However, the haze only allows instruments to detect the upper 150-300 km (90-190 miles). This prohibits scientists from gathering information about the lower parts of the atmosphere, which is more dense and has complex attributes.

“People had dreamed up rules for how planets would behave when seen in transit, but Titan didn’t get the memo,” said co-author Mark Marley. “It looks nothing like some of the previous suggestions, and it’s because of the haze.”

The team also found that the haze was more likely to block out blue light, which has a shorter wavelength. This could have considerable implications for previous analyses of exoplanets, as current models are based on the assumption that all wavelengths in the visible spectrum would be equally affected. 

The technique used on Titan could also be applied to Mars and Saturn. Using the information gathered from within our own solar system in the search for exoplanets greatly extends the usefulness of the orbiters and will allow scientists to gather more information about other worlds in the Universe.

Read more: http://www.iflscience.com/space/titan%E2%80%99s-sunsets-give-insight-hazy-atmospheres-exoplanets

Earth Used To Be Orange

TodayEarth is a pale blue dot, as famously coined by the late Carl Sagan. But 2.5 billion years ago, it would have been a pale orange dot owing to the methane produced by organisms and finding exoplanets that look similar could suggest they, too,have life on their surface.

This is according to a new study by Giada Arney from the University of Washington and her colleagues, presented atthe American Astronomical Societys Division for Planetary Sciences conference inMaryland this week. The research used geological data to examine what Earth would have looked like in the Archaean era, 2.5 billion years ago, and see if this appearance could help in the hunt for habitable exoplanets. Turns out, it might.

During this era, methane molecules in the atmosphere broken downby light formed complex hydrocarbons, organic compounds of hydrogen and carbon, giving Earth an orange haze, or smog, that would have been visible from space. There are two possible sources for such methane biological, namely life, or geological processes, such as on Saturn’s moon Titan. Thus, finding exoplanets with anorange hue could suggest they are going through a similar process to that which occured on theyounger Earth.

As Arney explains, to find out if an exoplanets orange hue comes from biological or geological processes, youll need to find out how much carbon dioxide is there. If its a lot, it could be Earth-like; if not, its probably more like Titan.

If we saw a hydrocarbon haze in an exoplanets atmosphere, it could suggest a methane source consistent with biological methane production, but it isnt enough to just detect the haze, she told IFLScience. To argue that the haze is a sign of life, youd have to also characterize the background atmosphere, particularly the amount of carbon dioxide.

Arney said Archaean Earth’s hue would have been similar to Titan, shown. NASA

On Earth, our haze which would have extended 20 to 70 kilometers (12 to 43 miles)into the atmosphere eventually gave way to the relatively bluer appearance we have today as the amount of oxygen grew. Oxygen destroys methane, so once levels started rising 2.5 billion years ago, the haze disappeared for good. But its a good indicator of biosignatures.

At the moment, we know of a few exoplanets that have hazes or clouds in their atmospheres, but we cant be sure they are Earth-like hydrocarbon hazes just yet. Future telescopes like the James Webb Space Telescope(JWST), though, could potentially characterize them.

Perhaps, in the continuing search for worlds like Earth, we may have to start looking for more of these pale orange dots.

The study will be published in the journal Astrobiology.

Read more: http://www.iflscience.com/space/earth-used-look-orange

Titan Smells Like Gasoline And Farts

Saturn’s largest moon, Titan, is of particular interest to scientists because of its unusually Earth-like qualities. Prior to the arrival of NASA’s Cassini spacecraft, Titan was difficult to study because it is shrouded in a thick golden haze of photochemical smog that obscured its surface. Observations gathered by this instrument have transformed investigations of this curious moon, and now a novel set of laboratory experiments has teased out even more information.

Using Cassini data, a team of NASA scientists has got tantalizingly close to recreating an unknown material discovered in Titan’s hazy atmosphere, furthering our knowledge of its composition.

This unidentified material was detected using Cassini’s Composite Infrared Spectrometer which collects spectral data in far-infrared regions. The signature of this material suggested that it was composed of several different ingredients, but what precisely these were remained a mystery.

In order to figure out the possible constituents, scientists used a trial and error method of combining different mixtures of gases in a chamber and seeing what came out. The team knew that if they could get the concoction right, then under the correct conditions it should be possible to recreate the unknown material. Although this may sound relatively simple, given the number of possible combinations this was no mean feat.

The team started off their experiments by combining the two most abundant gases in Titan’s atmosphere, nitrogen and methane, but the resulting mixtures never matched up with the signature picked up by Cassini. So the team experimented by throwing something else into the mix; aromatic hydrocarbons. These are hydrocarbons that contain one or more benzene ring. Since these are partly responsible for Titan’s burnt orange color this seemed logical.

The researchers began with the simplest aromatic hydrocarbon, benzene, which has been previously detected in Titan’s atmosphere and then worked their way through a list of closely related aromatic compounds.

They discovered the best spectral match to the Cassini data when they added aromatic hydrocarbons containing nitrogen, which are part of a subgroup known as polycyclic aromatic nitrogen heterocycles. These are polycyclic aromatic (contain more than 1 aromatic ring) hydrocarbons where carbon atoms have been replaced by nitrogen.

“Now we can say that this material has a strong aromatic character, which helps us understand more about the complex mixture of molecules that makes up Titan’s haze,” said planetary scientist Melissa Trainer in a news-release.

Although the spectral signatures were not identical when the team aligned them, they were strikingly similar which suggested that the scientists were very close to the right combination.

“This is the closest anyone has come, to our knowledge, to recreating with lab experiments this particular feature seen in the Cassini data,” said co-lead author of the study Joshua Sebree.

The team will now continue to play with the experimental conditions in order to hopefully yield a better fit to the Cassini signature.

“With the combination of laboratory experiments and Cassini data, we gain an understanding of just how complex and wondrous this Earth-like moon really is,” said Cassini Deputy Project Scientist Scott Edgington. 

Read more: http://www.iflscience.com/space/titan-smells-gasoline-and-farts

First Extraterrestrial Waves Ever Spotted On Titan

 
Saturn’s largest moon, Titan, looks a lot like Earth, except in deepfreeze. It’s got a nitrogen atmosphere, along with lakes and seas, channels sculpted by rivers, and even mudflats and rain clouds. The moon is so much like our planet that it’s a frequent setting for sci-fi: the (spoiler alert) promised land for Tom Cruise’s character in Oblivion, as well as the setting for Kurt Vonnegut’s second novel.
 
But while Titan appears so earthlike in so many ways, it’s still a very alien place. The moon’s lakes and seas are not made of H2O — at minus 290 degrees Fahrenheit, Titan’s surface is way too cold for liquid water. Researchers believe their water is actually a mixture of hard-to-freeze hydrocarbons like methane. And Titan’s lakes are eerily smooth: where are the waves? After all, “We know there is wind on Titan,” says Alex Hayes of Cornell University. “The moon’s magnificent sand dunes [prove] it.” 
 
NASA’s Cassini spacecraft may have found the answer. Cassini, which has been in Titan’s neighborhood since 2004, completed its 100th flyby earlier this month. Soon, and for the first time since Cassini arrived, spring will be turning to summer in Titan’s northern hemisphere (where most of the seas are), with the solstice in 2017. (Saturn takes about 29 Earth years to go around the Sun.) Scientists are really excited for this upcoming change in seasons, hoping that waves and winds on northern Titan will pick up.
 
Now, after years of searching for some telltale ripples, researchers say they may have detected waves in two of Titan’s lakes. If confirmed, this would be the first discovery of ocean waves beyond Earth, Nature News reports
 
In 2012 and 2013, Cassini spied “specular reflections” of the Sun, or glints of sunlight off the surface of Punga Mare, one of Titan’s seas. Those reflections may come from tiny ripples no more than a couple of centimeters high disturbing the otherwise flat ocean, according to University of Idaho’s Jason Barnes, who presented at a conference on Tuesday.
 
Four pixels in the images taken by an onboard spectrometer are brighter than you’d expect from reflecting sunlight, Barnes explains, which means they could represent something particularly rough on the surface, like a wave or set of waves.
 
Another talk at the conference also hinted at waves. In 2013, Cassini spotted a mysterious island in another sea, Ligeia Mare, that appeared and then disappeared. It looked like a bright reflection in one image but couldn’t be found in any photographs taken since, according to Cornell’s Jason Hofgartner. The team concluded that the mysterious island is probably a set of waves, a group of bubbles rising from below the surface, or even a suspended mass, like an iceberg.
 
However, while a Cassini flyby later this summer should be able to image this particular area of Ligeia Mare again, there’s no guarantee that the probe will pass by Punga Mare in the right position again before the end of its mission in 2017.
 
Regardless, “Titan may be beginning to stir,” says Ralph Lorenz of the Johns Hopkins University Applied Physics Laboratory. “Oceanography is no longer just an Earth science.” Lorenz, Barnes, Hayes, and the Cassini RADAR team published a global topographic map of Titan last year.
 
The findings [abstracts here and here] were presented at the Lunar and Planetary Science Conference taking place in Texas this week. 
 
[Via Nature]
 
Image: Titan’s hydrocarbon lakes taken by Cassini / NASA/JPL-Caltech/University of Arizona/University of Idaho
 

Read more: http://www.iflscience.com/space/first-extraterrestrial-waves-ever-spotted-titan

Cassini Probes Lakes On Titan

In a bid to further our knowledge of one of Saturn’s moons, Titan, a team of ground-based scientists successfully carried out a tricky maneuver last Wednesday using NASA’s Cassini spacecraft that allowed them to bounce a radio signal off the moon’s surface, sending information back to a receiver located 1 billion miles away on Earth. It is hoped that the data gathered will shed light on the composition of Titan’s vast liquid regions.

Titan, the largest of Saturn’s 62 moons, has attracted a lot of attention in recent years because of its bizarrely Earth-like qualities. Titan is cloaked in a dense, golden haze that obscures our view of its surface and kept its secrets hidden for many years. But data gathered recently, in particular observations from the Cassini spacecraft, has lifted the veil on this moon, revealing many unique features.

Much like Earth, Titan’s atmosphere is predominantly composed of Nitrogen and its surface is decorated with seas, lakes and flowing rivers. It has been hypothesized that rather than being filled with liquid water, they are composed of liquid methane or ethane. However, this suggestion is not based on direct observation but rather the fact that the conditions on Titan would result in methane and ethane being in a liquid state

“There is no really direct measurement that tells us what they are exactly,” Essam Marouf, a member of the Cassini radio science team, told LA Times. “If the data from this morning is good enough, it will tell us what these liquids really are.”

Marouf explains that they are basically using Titan as a mirror to bounce the Cassini radio signal back to Earth. The nature of this echo, which is picked up by a telescope array in Australia, should then hopefully give us a more thorough understanding of Titan’s surface.

While a similar operation was carried out back in May, at that time scientists were using Cassini to gather data on two of Titan’s vast seas; Ligea Mare and Kraken Mare. This time they directed the radio signal towards an area between these two seas which is known to contain smaller bodies of liquid.

Researchers are currently analyzing the data and hope to present the results at a Cassini meeting next week. 

[Via Los Angeles Times

Read more: http://www.iflscience.com/space/cassini-probes-lakes-titan

Titan’s Ocean is as Salty as the Dead Sea

Data from NASA’s Cassini spacecraft reveal that the ocean inside Saturn’s largest moon, Titan, could be as salty as the Dead Sea — the super-saline lake at the lowest spot on Earth. The findings were published in Icarus this week. 

Previous data have indicated that Titan’s icy shell — which overlies an ocean — is rigid and currently in the process of freezing solid. During its repeated flybys of Titan over the last decade, Cassini has collected a multitude of gravity and topography data, and scientists have now used them to create a model structure of the giant moon. 

After analyzing the gravity anomalies seen in the new data, a team led by Giuseppe Mitri of the University of Nantes, France, determined that the underlying ocean must have a relatively high density. That means Titan’s ocean is likely an extremely briny mix of water and dissolved salts, likely composed of sulfur, sodium, and potassium. Its density would give the ocean a salt content like that of the saltiest bodies of water on our planet. 

“This is an extremely salty ocean by Earth standards,” Mitri says in a news release. “Knowing this may change the way we view this ocean as a possible abode for present-day life, but conditions might have been very different there in the past.” The freezing process would also limit the exchange of materials between the surface and the ocean.

Additionally, they found that the thickness of the ice crust varies slightly from place to place around the moon. This further confirms that the outer shell is stiff, which would be the case if the ocean was slowly crystalizing and turning to ice. Otherwise, the shape of the moon would even itself out over time, like hot wax.

Another consequence of a rigid ice shell is that any outgassing of methane into the atmosphere must happen at scattered hot spots, like the ones that gave rise to the Hawaiian Islands. At the moment, Titan’s atmosphere contains about five percent methane. 

Read more: http://www.iflscience.com/space/titan%E2%80%99s-ocean-salty-dead-sea