Tag Archives: cassini

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

5 Craters That Look Like Other Things

5-craters-that-look-like-other-things-pics--3aa7a51a18

Newly-Released Maps of Saturn’s Moons Are The Clearest Ever Created

In the decade that the Cassini spacecraft has been orbiting Saturn, it has returned some pretty incredible images. Highlights include a clear view of Saturn’s hexagonal storm at the north pole, Saturn and a crescent Titan, and sunlight reflecting off of Titan’s seas. The latest addition to Cassini’s impressive portfolio is a collection of the most detailed colored maps of six of Saturn’s largest icy moons, excluding Titan. The images were taken throughout Cassini’s mission and were processed by Paul Schenk at the Lunar and Planetary Institute in Texas. 

“Getting feature locations in planetary images is a complex business,” Schenk wrote on his blog, StereoMoons. In the blog post, he discusses the challenges of sifting through all of the images to make a cohesive mosaic map.

Some of the images obtained by Cassini used colors that exist outside of normal human vision. Utilizing the near-infrared and ultraviolet wavelengths revealed structures that could not be seen otherwise. Differences in color that can be seen within our visual spectrum depict charged particles, gas, and dust that are being vented from the planet. The differences in color is predicted to be due to differences in thickness of those features.

Though these maps are quite exceptional, they aren’t completely finished. The area surrounding the north pole of Enceladus and a couple of regions on Iapetus require more imaging, which Cassini is expected to complete in 2015.

Having detailed maps of the moons’ topography will be important for future research. Knowing where landmarks exist on these satellites will give scientists a frame of reference when studying key features, in addition to allowing them to track any geological changes that occur on the surface of the moons. Future missions that may require the use of a lander are more likely to be successful if possible landing sites can be identified ahead of time and the terrain is well-understood. This has the potential to save a considerable amount of time and money.

Cassini’s primary mission ended on July 30, 2008, but had been extended twice. The orbiter is expected to remain operational until it runs out of fuel in 2017. Cassini will be directed to enter Saturn’s atmosphere at the end of its mission. Because the moons Titan and Enceladus are two of the top candidates for possible extraterrestrial life, Cassini’s operators do not want to risk the spacecraft accidentally contaminating those locations.

Mimas

NASA / JPL-Caltech / Space Science Institute / Lunar and Planetary Institute

Enceladus

NASA / JPL-Caltech / Space Science Institute / Lunar and Planetary Institute

Tethys

NASA / JPL-Caltech / Space Science Institute / Lunar and Planetary Institute

Dione

NASA / JPL-Caltech / Space Science Institute / Lunar and Planetary Institute

Rhea

NASA / JPL-Caltech / Space Science Institute / Lunar and Planetary Institute

Iapetus

NASA / JPL-Caltech / Space Science Institute / Lunar and Planetary Institute

If you’d like to see these maps with a side-by-side comparison of maps generated from Voyager data from the early 1980s, check it out on JPL’s website.

Credit: Global maps of Saturnian moons Mimas, Enceladus, Tethys, Dione, Rhea, Iapetus were produced by Dr. Paul Schenk (Lunar and Planetary Institute, Houston, TX) Image data are from the Imaging Science Subsystem (ISS) camera on the Cassini orbiter (NASA, JPL).

[Hat tip: Space.com]

Read more: http://www.iflscience.com/space/newly-released-maps-saturn-s-moons-are-clearest-ever-created

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.

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

Starlight Reveals The Complexity Of Enceladus Jets

Enceladus is one of the most promising candidates to find life elsewhere in the Solar System. The Saturnian satellite is an icy moon with water-rich plumes being ejected from its south polar region, an indication of a potential subsurface ocean of liquid water.

These plumes have been studied in detail by NASA’s Cassini spacecraft, butin the latest run of observations, astronomers spotted something that didnt fit predictions. The plumes are made by smaller jets, which appear to get stronger when the moon is farther away from Saturn. The probe detected one particular jet that was emitting four times more water than expected.

The observations were possible thanks to the light from the star Epsilon Orionis, the middle star in Orions belt, passing through Enceladus. On March 11,the moons plume andthe star were aligned with the Cassini spacecraft, and the probe was able to use itsUltraviolet Imaging Spectrometer (UVIS) to snap some pictures.

Cassini had previously observed three times as much icy dust being ejected from the moon around the furthest point from Saturn, but until now scientists had not been able to see if the water vapor increased as well, as water makes up for 90 percent of the material in the plume.

The moon at its closest point (right) and furthest (left).NASA/JPL-Caltech/University of Arizona/Cornell/SSI

Surprisingly they discovered that the plumes, which extend out to 500 kilometers (310 miles) from the surface, only had a 20 percent increase in the total amount of gas. Something must be propelling the icy dust outwards, so the team looked at the small jets that are closer to the surface. One jet, in particular, was seen to provide 8 percent of the plumes’ water content, instead of the usual 2 percent.

“We had thought the amount of water vapor in the overall plume, across the whole south polar area, was being strongly affected by tidal forces from Saturn,” said Larry Esposito, UVIS team leader, in astatement.”Instead, we find that the small-scale jets are what’s changing.”

While the new observations took an unexpected turn, the data collected will give physicists a better understanding on how Saturn heats up the interior of Enceladus.

“Since we can only see what’s going on above the surface, at the end of the day, it’s up to the modelers to take this data and figure out what’s going on underground,” added Candy Hansen, who led the planning of the observation.

Understanding the processes within Enceladus will give us better constraints on the potential subsurface ocean, and even what the chances are of life forming on this curious moon.

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Read more: http://www.iflscience.com/space/starlight-reveals-complexity-enceladus-jets

Where Is Planet Nine?

How close arewe tofinding Planet Nine? A new paper seems to suggest that the solution to the mystery is actually much closer than we previously thought.

Matthew Holman and Matthew Payne fromthe Harvard-Smithsonian Center for Astrophysics have used observations by the Cassini spacecraftto reduce the potential area in the sky where Planet Nine might be hiding. The region is found in the southern sky, roughly in the direction of the constellation of Cetus. The likely area extends over 20 degreesin all directions;by comparison,the full moon measuresonly half a degree across.

Planet Nine is a hypothetical planet proposed in January by Mike Brown and Konstantin Batygin to explain why objects beyond the orbit of Neptune have their closest point to the Sun in the same location.

In February, French researchers announced that by using data from the NASA/ESA Cassini spacecraft orbiting Saturn, they were able to narrow down the area where Planet Nine might be hiding. They used the perturbations, or lack thereof,in Saturn’s orbitto establish where the planet might be. Saturn would only be perturbed if Planet Nine was at its closest approach, so not seeing any perturbationstells us that Planet Nine is not very close to the Sun right now.

In the latest study, available online, the two researchers used a sophisticated statistical technique called MarkovChain Monte Carlo to reduce the potential hiding place of Planet Nine even further. While the data from Cassini doesnt showany perturbations that cannot be explained with current models, those studies dismiss the perturbations as noise.Holman andPayne, therefore, decided to lookfor potential Planet Nine models that would not onlyfit the values, but alsobolster support for the perturbations as a real effect.

We put Planet Nine at a whole different slew of locations all different possibilities on the sky, different distances, different masses and tried to find out whether that constrains things even more, said Payne to New Scientist.

According to the model, Planet Nine could be located in two narrow strips of the sky. The team thenoverlapped these regions with Batygin and Browns suggested orbit and got an even smaller area.

Astronomers are already looking at the suggested region andwillhopefully soon find out whether there are nine planets in the Solar System.

[H/T:New Scientist]

Read more: http://www.iflscience.com/space/scientists-further-reduce-search-area-planet-nine

This Stunning Image Of Saturn’s Rings Contains A Surprise

If youre confused by this image, we dont blame you. What youre seeing here are the rings of Saturn and the gas giant itself. But the planets rings are, well, rings. Why do they appear to be criss-crossing each other here?

The answer is a pretty awesome illusion, snapped by the Cassini spacecraft thats currently in orbit around Saturn. The bulk of the image is the rings itself, while in the background is the planet Saturn. The lines going the other direction to the rings are actually the shadow of the rings on the planet, visible because the rings are semi-transparent.

Thats not the only surprising thing about this image, though. Take a look just below the middle, and youll spot a gap in one of the rings with a white dot in it. This gap is known as the Encke gap, and the white dot is the moon Pan (28 kilometers/17 miles across). Moons like this form gaps by cleaning out debris from the rings.

Now you see it… NASA/JPL-Caltech/Space Science Institute

Cassini took this image from a distance of 1.9 million kilometers (1.2 million miles) from Pan on February 11, 2016, with a scale of 10 kilometers (6 miles) per pixel. The spacecraft arrived in orbit around Saturn in 2004, and since then it has provided uswith incredible views and data from Saturn and its various moons, including Enceladus and Titan.

But, sadly, all good things must come to an end. On September 15 next year, the spacecraft will be sent to its death in the atmosphere of Saturn. This is because, as it runs out of fuel, NASA wants to ensure it wont accidentally hit one of the potentially life-harboring moons and contaminate it with material from Earth.

Dont despair too much, though, because this final death plunge will see Cassini return some groundbreaking science to Earth. Itll be sending back data constantly until its final moments, so well get incredible data from within Saturns rings and from its upper atmosphere as well something weve never gotten before.

Until then, bask in the glory of images like these. With no other spacecraft to Saturn currently in the works, we really shouldn’t take Cassini for granted.

Here’s the full image in all its glory.NASA/JPL-Caltech/Space Science Institute

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Read more: http://www.iflscience.com/space/stunning-image-saturn-contains-more-one-surprise

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

Cassini Bids Farewell To Saturn’s Enceladus In Final, Remarkable Flyby

Say goodbye to Enceladus: The Cassini spacecraft has finished its final flyby of the mysterious icy moon ofSaturn. After receiving streams of data over the weekend, NASA has showcased some of the most beautiful astrophotography taken by the probe. Passing at a distance of 4,999 kilometers (3,106 miles) from the surface of the moon, the final series of images reveals the worlds furrows and ridges in impeccable detail.

This final Enceladus flyby elicits feelings of both sadness and triumph, said Earl Maize, Cassini project manager at NASAs Jet Propulsion Laboratory (JPL), in a statement. While we’re sad to have the close flybys behind us, we’ve placed the capstone on an incredible decade of investigating one of the most intriguing bodies in the Solar System.

The final flyby was Cassinis 22nd, and was by no means its most dramatic. An earlier flyby saw the probe skimjust 48kilometers (30 miles) above the surface of Enceladus south pole, a region featuringspectacular plumes breaking through the ice and launching into space. Some have termed these icy jets as an example of cryovolcanism: volcanic eruption columns made entirely of ice.

Image credit: Samarkand Sulci, one of the tiger stripes of Enceladus likely formed by very young tectonic activity. This feature is 383 kilometers (238 miles) in length. NASA

This year, Cassini confirmed that there is a global ocean beneath the surface of Enceladus, one which is warm enough to produce these icy plumes. These plumes actually replenish one of Saturns famous rings, in this case the E ring. Although the formations on Pluto are more likely to be bonafide ice volcanoes, these plumes are still spectacular, and important: they may contain compounds indicative of biological processes operating beneath the surface.

Some scientists have speculated that this Saturnian moon, therefore, may be a prime candidate in our search for extraterrestrial life. By flying the spacecraft directly into one of these plumes in order to collect samples, NASA hoped to find evidence for this remarkable possibility. The data is still being analyzed, so only time will tell in this respect. Organic molecules, the building blocks of life on Earth, have already been confirmed to be present in these plumes.

Image credit: Enceladus northern territory. The terrain in the left part of this image has almost no craters, meaning it must be quite young. NASA

Scientists noted that themoon generates internal heat using the same mechanism that that powers the fiery, hellish volcanism of Jupiters moon Io. In Ios case, the massive pull of Jupiters gravity, enhanced by its interaction with two other nearby moons, exerts an incredible gravitation force on its subsurface; this rips apart solid rock, causing it to melt.

In the case of Enceladus, the same mechanism, albeit a weaker variant, comes from its celestial dance with Saturn. This is known as tidal heating, demonstrated in two remarkably different ways in Enceladus and Ios song of ice and fire.

Enceladus, 1.4 billion kilometers (890million miles) from Earth, still holds many mysteries, and its likely that only a handful will be unraveled by the data streaming back from Cassini as it begins to turn its focus to Saturn itself.

We bid a poignant goodbye to our close views of this amazing icy world, said Linda Spilker, the mission’s project scientist at JPL. The spacecraft will continue its tour of the Saturnian system until September 2017, whereupon it will complete its Solstice Mission by dramatically entering Saturns atmosphere.

Read more: http://www.iflscience.com/space/cassini-bids-farewell-saturns-enceladus-final-remarkable-flyby

Ten Of The Most Awe-Inspiring Space Images Of 2015

2015 has been a pretty awesome year for space exploration. It has seen the likes of the New Horizons flyby of Pluto, private enterprises making some ground-breaking developments, and a whole manner of less “front-page news,” which is nonetheless slowly but surely helping us increase ourunderstanding of the vast intergalactic heavens.

Furthermore, public imagination and pop culture have both been reinvigorated with 20th century Space Race-like curiosity, with films like “The Martian” and “Star Wars: The Force Awakens” proving to be some of the most popular releases.

Whether you have a fledgling interest or you’re a full-blown space nut, nothing quenches our cosmic thirst more than beautiful images of space. But, these images arent simply screensaver-fodder or PR props for their relevant space agencies. Many of these images are the products of intense scientific exploration or express a landmark in the history of space travel. Beauty is truth, truth beauty, as they say.

1. Scott Kelly tweets from theInternational Space Station

Scott Kelly has been up on the International Space Station (ISS) since March, 2015, along with Russian cosmonaut Mikhail Korniyenko. Together theyll spend just under a whole year in space to study long-term effects of spaceflight on the human body. In the meantime, aside from conducting numerous experiments, Kelly spends his time snapping some of the most colorful, beautiful and trippy images of space. Theres almost too many images to list, as Kelly uploads a new one at least once a day, so make sure you give him a follow on Twitter.

2. Saturn,her ringsand tethys

This image was taken in visible light on August 18, 2015, by the Cassini spacecraft. With a simple monochrome effect, it shows the rings of Saturn sitting behind Tethys, one of Saturns moons, from over 296,000 kilometers (184,000 miles) away.

Image credit: NASA

3. “Bloodstains” on Saturn’s moon

Another image from the Cassini mission shows bizarre red streaks cutting across the icy surface of Saturns moon Tethys around early springtime this year. The image is made from numerous clear, green, infrared, and ultraviolet spectral filtered images to bring out subtle color wavelengths the human eye cant normally see.

Image credit: NASA

4. Flowing water on mars

Not only is this photograph visually stunning, it is also up there with one of the most exciting scientific discoveries of the year. The image, from NASA’s Mars Reconnaissance Orbiter (MRO), shows a strong indication that Mars once had flowing water suggesting the Red Planet had the ability to harbor life. The streaks trailing down those mountains appear to detail the path in which salty liquid water used to flow like Martian rapids.

Image credit: NASA

5. Rosetta captures an comet gas outburst

This snapshot, showing a short-lived burst of gas from comet 67P/Churyumov-Gerasimenko, was captured by Rosetta’s OSIRIS narrow-angle camera on July 29, 2015. Rosetta is the first spacecraft to orbit a comet, as well as the first spaceship to travel alongside a comet as it travelled in the direction of the Sun.

Image credit: NASA/ESA

6. Blue Originand theage of private enterprise in space

Space exploration is no longer the domain of government agencies. With the likes of Elon Musks SpaceX and Amazon founder and CEO Jeff Bezos’ company Blue Origins, private space companies have made some pretty big cosmic leaps in 2015.

In homage to this, heres an image showing Blue Origins New Shepard spacecraft’s historiclaunch from Van Horn, Texas, on November 24, 2015. This launch was the first to use a reusable space vehicle to travel out to space and successfully return to land intact. It was followed by SpaceX’s arguably more impressive landing a month later.

Image credit: Blue Origin

7. Hubble and the “butterfly” nebula

Hubble never ceases to amaze with their mouse mat-friendly imagery. This photograph shows the planetary nebula known as PN M2-9. And this twin jet nebula is not any old planetary nebula;it is a bipolar nebula comprised of two “suns.” The motion of these two stars endowit with this rather beautiful butterfly-esque effect.

Image credit: NASA/ESA/Hubble

8. Psychedelic Pluto

In July, after an epic nine-year journey, the New Horizons spacecraft finally reached humanitys closest approach of Pluto, around 12,500 kilometers (7,800 miles) above its surface. Already, the fruits of this mission have been juicy, as well as providing some stunning images. Although this is a particularly funky image of this dwarf planet, false colors have been added to highlight differences in the soil composition.

Image credit: NASA

9. The 1.5 billion pixel image of theAndromeda Galaxy

Right at the start of 2015, NASA and the European Space Agency (ESA) released a 1.5 billion pixel image of Andromeda, the Milky Ways nearest major galactic neighbor. To truly do justice to this feat of imagery, you need to go to the Hubble site, where it is possible to zoom into patches of the galaxy.

Image credit: NASA/ESA

10. Time-lapse of the Sun

2015 saw us celebrating five years of NASA’s Solar Dynamics Observatory being in space. Overall, the project has captured more than 2,600 terabytes of data and 200 million images of the Sun in an attempt to better understand the Solar-Earth relationship. The observatory captures an image around every second;this video is just a little “best of” compilation.

Photo Gallery

Read more: http://www.iflscience.com/space/top-10-space-images-2015