Cassini Archives

July 7, 2014December 23, 2015 by Elizabeth Howell

Sketches of Saturn: Ringed Planet Dances In Raw Cassini Images

A hexagonal storm on Saturn rages in this image taken July 2, 2014. Credit: NASA/JPL/Space Science Institute

We space people are very lucky to get glimpses of Saturn (and other planets!) regularly through the raw images feature on a few spacecraft websites. This allows anyone to get a hold of the pictures as they come back from afar, allowing you to view them or alter them to try and see what they’re all about.

In an era where we are so used to high-definition pictures, examining these blurry, black-and-white shots feels novel. It makes the spacecraft seem like it is action somehow: catching a glimpse of a ringed planet as it swings by, for example.

Enclosed here are some of the latest gifts from the Cassini spacecraft, which is celebrating 10 years in Saturn’s system.

Part of Saturn's rings are visible in this July 2, 2014 image from the cassini spacecraft. Credit: NASA/JPL/Space Science Institute — Part of Saturn’s rings are visible in this July 2, 2014 image from the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute

Gazing at Saturn's rings. Picture taken by the Cassini spacecraft June 30, 2014. Credit: NASA/JPL/Space Science Institute — Gazing at Saturn’s rings. Picture taken by the Cassini spacecraft June 30, 2014. Credit: NASA/JPL/Space Science Institute

A dark shadow falls across Saturn and its rings in this raw image taken by the Cassini spacecraft July 2, 2014. Credit: NASA/JPL/Space Science Institute

Eerie shadows play across Saturn in this Cassini image taken in June 2014. Credit: NASA/JPL/Space Science Institute

June 30, 2014December 23, 2015 by Elizabeth Howell

Saturn’s Sailor: 20 Cassini Pictures Marking A Decade At The Ringed Planet

Saturn's northern storm marches through the planet's atmosphere in the top right of this false-color mosaic from NASA's Cassini spacecraft. Credit: NASA/JPL-Caltech/Space Science Institute

We’re spoiled, don’t you know? It was 10 years ago today that the Cassini spacecraft entered Saturn’s system, and it has been busily beaming back pictures of the ringed planet and its (many) moons ever since. We’ve learned more about seasons on Titan, investigated plumes on Enceladus, and examined phenomena such as auroras on Saturn.

Embedded in this story are 20 of our favourite pictures from Universe Today’s archive of Cassini discoveries, which you can check out below the jump.

It’s only a fraction of the more than 332,000 images received from the spacecraft, which is in excellent health and has seen its mission extended three times past its original 2008 expiry date. Additionally, more than 3,000 scientific papers have been generated. More cool stats in this NASA infographic.

And by the way, we’re not the only ones assembling memorable images to mark the anniversary. Check out NASA’s favourite Cassini pictures of the past decade, or our friend Phil Plait’s Bad Astronomy list. Also, here is NASA’s opinion of the top 10 discoveries at the ringed planet.

While thinking about Cassini, also don’t forget Huygens, the lander that descended to the surface of Titan in 2005. More on that in this past Universe Today anniversary story.

The full mosaic from the Cassini imaging team of Saturn on July 19, 2013… the “Day the Earth Smiled”

In this unique mosaic image combining high-resolution data from the imaging science subsystem and composite infrared spectrometer aboard NASA's Cassini spacecraft, pockets of heat appear along one of the mysterious fractures in the south polar region of Saturn's moon Enceladus. Image credit: NASA/JPL/GSFC/SWRI/SSI — In this unique mosaic image combining high-resolution data from the imaging science subsystem and composite infrared spectrometer aboard NASA’s Cassini spacecraft, pockets of heat appear along one of the mysterious fractures in the south polar region of Saturn’s moon Enceladus. Image credit: NASA/JPL/GSFC/SWRI/SSI

Saturn, imaged by Cassini on approach. Credit: CICLOPS

Titan and Dione as seen by Cassini. Credit: NASA/JPL/Space Science Institute

Which Planets Have Rings? — This image taken by the Cassini orbiter on Oct. 15, 2007, shows Saturn’s A and F rings, the small moon Epimetheus and smog-enshrouded Titan, the planet’s largest moon. The image is colorized to approximate the scene as it might appear to human eyes. (Credit: NASA/JPL/Space Science Institute)

Cassini imaging scientists used views like this one to help them identify the source locations for individual jets spurting ice particles, water vapor and trace organic compounds from the surface of Saturn's moon Enceladus. Credit: NASA — Cassini imaging scientists used views like this one to help them identify the source locations for individual jets spurting ice particles, water vapor and trace organic compounds from the surface of Saturn’s moon Enceladus. Credit: NASA

Raw image from Cassini on May 18. Credit: NASA/JPL/SSI

Hemispheric color differences on Saturn's moon Rhea are apparent in this false-color view from NASA's Cassini spacecraft. This image shows the side of the moon that always faces the planet. Image Credit: NASA/JPL/SSI — Hemispheric color differences on Saturn’s moon Rhea are apparent in this false-color view from NASA’s Cassini spacecraft. This image shows the side of the moon that always faces the planet. Image Credit: NASA/JPL/SSI

Three of Saturn's moons bunch together in this image by Cassini. Credit: NASA/JPL/Space Science Institute. Click for larger image. — Three of Saturn’s moons bunch together in this image by Cassini. Credit: NASA/JPL/Space Science Institute. Click for larger image.

This mosaic of Titan was created from the first flyby of the moon by Cassini in 2004. Credit: NASA/JPL/SS

Phoebe imaged by the Cassini spacecraft. Image Credit: NASA

Cassini VIMS image of specular reflections in one of Titan's lakes from a flyby on July 24, 2012 (NASA/JPL-Caltech/SSI/Jason W. Barnes et al.) — Cassini VIMS image of specular reflections in one of Titan’s lakes from a flyby on July 24, 2012 (NASA/JPL-Caltech/SSI/Jason W. Barnes et al.)

A crescent Dione was seen by Cassini on January 29, 2011 from approximately 767,922 kilometers away. Credit: NASA/JPL/SSI

Cassini captured this startling image of Saturn's moon Hyperion. Photo Credit: NASA/JPL — Cassini captured this startling image of Saturn’s moon Hyperion. Photo Credit: NASA/JPL

ets of water ice particles spew from Saturn's moon Enceladus in this image obtained by NASA's Cassini spacecraft on Aug. 13, 2010. Image credit: NASA/JPL/SSI — ets of water ice particles spew from Saturn’s moon Enceladus in this image obtained by NASA’s Cassini spacecraft on Aug. 13, 2010. Image credit: NASA/JPL/SSI

This false-color composite image shows Saturn’s rings and southern hemisphere. The composite image was made from 65 individual observations by Cassini’s visual and infrared mapping spectrometer in the near-infrared portion of the light spectrum on Nov. 1, 2008. Credit: NASA/JPL/University of Arizona

This mosaic of images from NASA's Cassini spacecraft shows three fan-like structures in Saturn's tenuous F ring. Such "fans" suggest the existence of additional objects in the F ring. Image credit: NASA/JPL/SSI — This mosaic of images from NASA’s Cassini spacecraft shows three fan-like structures in Saturn’s tenuous F ring. Such “fans” suggest the existence of additional objects in the F ring. Image credit: NASA/JPL/SSI

Cassini came within 25 kilometers (15.6 miles) of the surface of Enceladus on Oct. 5, 2008. Image credit: NASA/JPL/Space Science Institute

June 24, 2014December 23, 2015 by Shannon Hall

Titan’s Atmosphere May be Older than Saturn, a New Study Suggests

Titan's atmosphere makes Saturn's largest moon look like a fuzzy orange ball in this natural-color view from the Cassini spacecraft. Cassini captured this image in 2012. Image Credit: NASA/JPL-Caltech/Space Science Institute — According to a study from UCLA, Titan experiences severe methane rainstorms, leading to a the alluvial fans found found in both hemispheres. Credit: NASA/JPL-Caltech/Space Science Institute

It’s well accepted that moons form after planets. In fact, only a few months ago, astronomers spotted a new moon forming deep within Saturn’s rings, 4.5 billion years after the planet initially formed.

But new research suggests Saturn’s icy moon Titan — famous for its rivers and lakes of liquid methane — may have formed before its parent planet, contradicting the theory that Titan formed within the warm disk surrounding an infant Saturn.

A combined NASA and ESA-funded study has found firm evidence that the nitrogen in Titan’s atmosphere originated in conditions similar to the cold birthplace of the most ancient comets from the Oort cloud — a spherical shell of icy particles that enshrouds the Solar System.

The hint comes in the form of a ratio. All elements have a certain number of known isotopes — variants of that element with the same number of protons that differ in their number of neutrons. The ratio of one isotope to another isotope is a crucial diagnostic tool.

In planetary atmospheres and surface materials, the amount of one isotope relative to another isotope is closely tied to the conditions under which materials form. Any change in the ratio will allow scientists to deduce an age for that material.

Kathleen Mandt from the Southwest Research Institute in San Antonio and colleagues analyzed the ratio of nitrogen-14 (seven protons and seven neutrons) to nitrogen-15 (seven protons and eight neutrons) in Titan’s atmosphere.

“When we looked closely at how this ratio could evolve with time, we found that it was impossible for it to change significantly,” Mandt said in a press release. “Titan’s atmosphere contains so much nitrogen that no process can significantly modify this tracer even given more than four billion years of Solar System history.”

The team found that our Solar System is not old enough for this nitrogen isotope ratio to have changed as much as it has. By comparing the small change within this ratio, Mandt and colleagues found that it seemed more similar to Oort cloud comets than to Solar System bodies including planets and comets born in the Kuiper belt. The team is eager to see whether their findings are supported by data from ESA’s Rosetta mission, which will study comet 67P/Churyumov-Gerasimenko later this year.

Finally, the study also has implications for Earth. In the past, researchers assumed a connection between comets, Titan and Earth. But these results show that the nitrogen isotope ratio is different on Titan and Earth, suggesting the sources of Earth’s and Titan’s nitrogen must have been different.

It’s unclear whether Earth received nitrogen from early meteorites or if it was captured directly from the disk of gas that formed the Solar System.

“This exciting result is a key example of Cassini science informing our knowledge of the history of [the] Solar System and how Earth formed,” said Scott Edgington, Cassini deputy project scientist at NASA’s Jet Propulsion Laboratory.

The research was published this week in the Astrophysical Journal Letters.

June 23, 2014December 23, 2015 by Nancy Atkinson

‘Ghost’ Object Appears, Disappears on Titan

During previous flybys, 'Magic Island' was not visible near Ligeia Mare's coastline (left). Then, during Cassini's July 20, 2013, flyby the feature appeared (right)/ Credit: NASA/JPL-CALTECH/ASI/CORNELL, image editing via Ian O'Neill/Discovery News.

Astronomers with the Cassini mission have detected a bright, mysterious geologic object on Saturn’s moon Titan that suddenly showed up in images from the mission’s radar instrument. The object appeared in Ligeia Mare, the second-largest sea Titan. The feature looks like an island and so the team named it “Magic Island.” However, it most likely is not an island that suddenly surfaced. But scientists say this may be the first observation of dynamic, geological processes in Titan’s northern hemisphere.

The object suddenly showed up in images beamed back from Cassini on July 10, 2013, showing regions of Ligeia Mare, a sea located near Titan’s north pole. But then just as suddenly, in a follow-up flyby only days later on July 26, the island was gone. Subsequent flybys confirmed that Magic Island had vanished and is what is known as a “transient feature.”

“This discovery tells us that the liquids in Titan’s northern hemisphere are not simply stagnant and unchanging, but rather that changes do occur,” said Jason Hofgartner, a Cornell graduate student in the and the lead author of a paper appearing in Nature Geoscience. “We don’t know precisely what caused this ‘magic island’ to appear, but we’d like to study it further.”

Map of Titan's northern region of hydrocarbon 'seas' created from Cassini radar imaging. Credit: NASA/JPL/USGS. — Map of Titan’s northern region of hydrocarbon ‘seas’ created from Cassini radar imaging. Credit: NASA/JPL/USGS.

Titan is currently the only other world besides Earth known to have stable bodies of liquid on its surface. But unlike Earth, Titan’s lakes aren’t filled with water — instead they’re full of liquid methane and ethane, organic compounds which are gases on Earth but liquids in Titan’s incredibly chilly -290º F (-180º C) environment.

So what was this object? Among the explanations from the team are:

Northern hemisphere winds may be kicking up and forming waves on Ligeia Mare. The radar imaging system might see the waves as a kind of “ghost” island. Scientists previously have seen what they think are waves in another nearby Titan sea, Punga Mare.

Gases may push out from the sea floor of Ligeia Mare, rising to the surface as bubbles.

Sunken solids formed by a wintry freeze could become buoyant with the onset of the late Titan spring warmer temperatures.

Suspended solids in Ligeia Mare, which are neither sunken nor floating, but act like silt in a terrestrial delta.

“Likely, several different processes – such as wind, rain and tides – might affect the methane and ethane lakes on Titan. We want to see the similarities and differences from geological processes that occur here on Earth,” Hofgartner said. “Ultimately, it will help us to understand better our own liquid environments here on the Earth.”

Source: Cornell University

June 17, 2014December 23, 2015 by Elizabeth Howell

Pale White Dot: Saturn’s Moon Atlas Shines Between Gas Giant’s Rings

Saturn's moon Atlas peeks out between the rings in this Cassini shot taken Jan. 23, 2014. Credit: NASA/JPL-Caltech/Space Science Institute

See that small pixel? That’s an entire moon you’re looking at! Peeking between the rings of Saturn is the tiny saucer-shaped moon Atlas, as viewed from the Cassini spacecraft. The image is pretty, but there’s also a scientific reason to watch the planet’s many moons while moving around the rings.

“Although the sunlight at Saturn’s distance is feeble compared to that at the Earth, objects cut off from the Sun within Saturn’s shadow cool off considerably,” NASA stated.

“Scientists study how the moons around Saturn cool and warm as they enter and leave Saturn’s shadow to better understand the physical properties of Saturn’s moons.”

And if you look at Atlas close-up, it looks a little like a flying saucer! The moon is only 20 miles (32 km) across, which is a bit shy of the length of a marathon. The Voyager 1 team spotted the moon in 1980 when the spacecraft zoomed through the system. You can learn more about Saturn’s moons here.

Cassini is still in excellent health (it arrived at Saturn in 2004, and has been in space since 1997), and scientists are eagerly getting ready for when Saturn gets to its summer solstice in 2017. Among the things being looked at is a hurricane at Saturn’s north pole.

Saturn's moon Atlas. Left image: viewed from the side, at a scale of 0.6 miles (1 km) per pixel. Right image: the mid-southern latitudes, at 820 feet (250 m) per pixel. The images are composite views from the Cassini spacecraft. Credit: NASA/JPL/SSI — Saturn’s moon Atlas. Left image: viewed from the side, at a scale of 0.6 miles (1 km) per pixel. Right image: the mid-southern latitudes, at 820 feet (250 m) per pixel. The images are composite views from the Cassini spacecraft. Credit: NASA/JPL/SSI

June 16, 2014December 23, 2015 by Elizabeth Howell

New Recipe For Saturn’s Orangey Moon Titan Is ‘Aromatic’ And Hazy

A fish-eye view of Titan's surface from the European Space Agency's Huygens lander in January 2005. Credit: ESA/NASA/JPL/University of Arizona

What’s in all that browny orangey stuff in the atmosphere around Titan? It’s a question that scientists have been trying to answer concerning Saturn’s moon for decades (Carl Sagan was among them). That’s because it’s hard to reverse-engineer the recipe.

There are hundreds of thousands of hydrocarbons (hydrogen and carbon molecules) that could form the compounds in the atmosphere along with nitriles (nitrogen-abundant chemicals). But scientists are hoping that their new recipe gets a bit closer to understanding how the atmosphere works.

The researchers put gases inside of a chamber and monitored their reactions, starting with nitrogen and methane — the gases that are the most common in Titan’s atmosphere. Then they included benzene — which the Cassini spacecraft has detected in the atmosphere — along with close chemical relatives.

Titan's surface is almost completely hidden from view by its thick orange "smog" (NASA/JPL-Caltech/SSI. Composite by J. Major) — Titan’s surface is almost completely hidden from view by its thick orange “smog” (NASA/JPL-Caltech/SSI. Composite by J. Major)

In the end, it seemed the best third ingredient was choosing an “aromatic”, a sort of hydrocarbon, that includes nitrogen. That’s because the scientists saw that the spectrum of this gas appeared to be similar to what was spotted by Cassini.

“This is the closest anyone has come, to our knowledge, to recreating with lab experiments this particular feature seen in the Cassini data,” stated lead author Joshua Sebree, a former postdoctoral fellow at the NASA Goddard Space Flight Center who is now an assistant professor at the University of Northern Iowa in Cedar Falls.

Scientists say the recipe still needs some modifications, but this is a good start. The research is available in the journal Icarus.

Source: Jet Propulsion Laboratory

May 29, 2014December 23, 2015 by Elizabeth Howell

How Much Can Titan’s Sunsets Teach Us About Alien Planets?

An illustration of a Titanic lake by Ron Miller. All rights reserved. Used with permission.

Titan — that smoggy, orangy moon circling Saturn — is of great interest to exobiologists because its chemistry could be good for life. It has a thick atmosphere of nitrogen and methane and likely has lakes filled with liquid hydrocarbons, and scientists believe there is enough light filtering down into the atmosphere to drive chemical reactions.

It turns out the moon could also be a good analog to help us understand the atmospheres of exoplanets far beyond our solar system. From looking at sunsets on the moon, scientists led by NASA believe that a thick atmosphere could influence how we perceive a planet from afar.

First, a bit of information about how scientists learn about planet atmospheres in the first place. When a distant planet passes in front of its parent star, the light from the star passes through the atmosphere and gets distorted.

The spectra that telescopes pick up can then tell scientists information about what the atmosphere is made of, what temperature it is, and how it is structured. (This science, it should be noted, is in its very early stages and works best on very large exoplanets that are relatively close to Earth, since the planets are so small and far away.)

“Previously, it was unclear exactly how hazes were affecting observations of transiting exoplanets,” stated Tyler Robinson, a postdoctoral research fellow at NASA’s Ames Research Center who led the research. “So we turned to Titan, a hazy world in our own solar system that has been extensively studied by Cassini.”

To do this, Robinson’s team used data from the Cassini spacecraft during four solar occultations, or times when Titan passed in front of our own sun from the perspective of the spacecraft. They found out that the moon’s hazy atmosphere makes it difficult to figure out what is in its spectra.

“The observations might be able to glean information only from a planet’s upper atmosphere,” NASA stated. “On Titan, that corresponds to about 90 to 190 miles (150 to 300 kilometers) above the moon’s surface, high above the bulk of its dense and complex atmosphere.”

The haze is even more powerful in the shorter (bluer) wavelengths of light, which contradicts previous studies assuming that all wavelengths of light would have the same distortions. Models of exoplanet atmospheres usually have simplified spectra because hazes are complex to model, requiring a lot of computer power.

Researchers hope to take these observations of Titan and then use them to better inform how exoplanet models are created.

The research was published May 26 in the Proceedings of the National Academy of Science.

Source: NASA

May 1, 2014December 23, 2015 by Jason Major

Cassini’s View of Another Pale Blue Dot

Uranus as seen by Cassini on July 19, 2013 (NASA/JPL-Caltech/SSI)

When you hear the words “pale blue dot” you’re probably reminded of the famous quote by Carl Sagan inspired by an image of Earth as a soberingly tiny speck, as imaged by Voyager 1 on Feb. 14, 1990 from beyond the orbit of Pluto. But there’s another pale blue world in our Solar System: the ice giant Uranus, and its picture was captured much more recently by the Cassini spacecraft from orbit around Saturn on April 11, 2014.

Released today by the Cassini Imaging Team, the image above shows Uranus as a tiny blue orb shining far beyond the bright hazy bands of Saturn’s F ring.

“Do you relish the notion of being a Saturnian, and gazing out from the lofty heights of Saturn at the same planets we see here from the Earth?”
– Carolyn Porco, Cassini Imaging Team Leader

Uranus’ coloration is a result of methane high in its frigid atmosphere. According to the description on the CICLOPS site, “methane on Uranus — and its sapphire-colored sibling, Neptune — absorbs red wavelengths of incoming sunlight, but allows blue wavelengths to escape back into space, resulting in the predominantly bluish color seen here.”

This was also the first time Uranus had been imaged by the Cassini spacecraft, which has been in orbit around Saturn since 2004. In fact its ten-year orbital anniversary will come on July 1.

This image adds one more planet to the list of worlds captured on Camera by Cassini, which made headlines last fall when a glorious mosaic was released that featured a backlit Saturn in eclipse surrounded by its luminous rings, the specks of several of its moons, and the distant dots of Venus, Mars, and the Earth and Moon. Made from 141 separate exposures, the mosaic was captured on July 19, 2013 — known by many space aficionados as “the day the Earth smiled” as it was the first time the world’s population was alerted beforehand that its picture would be taken from over 900 million miles away.

Saturn — with its terrestrial spacecraft in tow — was about 28.6 AU away from Uranus when the image was acquired. That’s about 4.28 billion kilometers (2.66 billion miles). From that distance the glow of the 51,118-kilometer (31,763-mile) -wide Uranus is reduced to a mere few pixels (which required digital brightening by about 4.5x, as well.)

Read more on the Cassini Imaging Central Laboratory for Operations (CICLOPS) page here and in a news release from NASA’s JPL here.

Image credit: NASA/JPL-Caltech/SSI. Source: Carolyn Porco, CICLOPS Director

April 21, 2014December 23, 2015 by Nancy Atkinson

Video: Carolyn Porco Discusses Her Life at Saturn

Planetary scientists Carolyn Porco. Via NASA/JPL.

Space historian Andrew Chaikin sat down with planetary scientist Carolyn Porco, and she discusses how her career has ended up focusing on the Saturn system. I love how Porco relates how even she has been “blown away” by some of the imagery sent back by the missions — just like the rest of us! — saying she’s had to call members of her team several times to verify she wasn’t looking at computer simulations vs. real images.

Enjoy this candid interview of one of the leading planetary scientists of our day.

April 14, 2014April 26, 2016 by Jason Major

Is Saturn Making a New Moon?

A 750-mile (1,200-km) -long feature spotted on Saturn's A ring by Cassini on April 15, 2013

Congratulations! It’s a baby… moon? A bright clump spotted orbiting Saturn at the outermost edge of its A ring may be a brand new moon in the process of being born, according to research recently published in the journal Icarus.

“We have not seen anything like this before,” said Carl Murray of Queen Mary University in London, lead author of the paper. “We may be looking at the act of birth, where this object is just leaving the rings and heading off to be a moon in its own right.”

In images acquired with Cassini’s narrow-angle camera in 2013, a 1,200-kilometer-long, 10-kilometer-wide arc of icy material was observed traveling along the edge of the A ring. The arc is thought to be the result of gravitational perturbations caused by an as-yet unseen embedded object about a kilometer wide — possibly a miniature moon in the process of formation.

Cassini image of the 179-km-wide Janus from April 2010. Janus' gravity may have helped spur the formation of Peggy. (NASA/JPL-Caltech/SSI) — Cassini image of 179-km-wide Janus from April 2010. Janus’ gravity may have helped spur the formation of Peggy. (NASA/JPL-Caltech/SSI)

The half-mile-wide object has been unofficially named “Peggy,” after lead author Murray’s mother-in-law (whose 80th birthday it was on the day he was studying the Cassini NAC images.) Murray first announced the findings on Dec. 10, 2013 at the AGU 13 meeting in San Francisco.

According to the team’s paper, Peggy’s effects on the A ring has been visible to Cassini since May 2012.

Eventually Peggy may coalesce into a slightly larger moon and move outward, establishing its own orbital path around Saturn. This is how many of Saturn’s other moons are thought to have formed much further back in the planet’s history. Now, its rings having been depleted of moon-stuff, can only create tiny objects like Peggy.

“Witnessing the possible birth of a tiny moon is an exciting, unexpected event.”
– Linda Spilker, Cassini Project Scientist at JPL

While it is possible that the bright perturbation is the result of an object’s breakup rather than formation, researchers are still looking forward to finding out more about its evolution.

To find out more about the Cassini mission visit saturn.jpl.nasa.gov and www.nasa.gov/cassini. The Cassini imaging team’s website is at ciclops.org.