Category Archives: Gas giants Saturn, Jupiter, et al

Cassini nears journey’s end + The plume of Enceladous + The rings in hi-res

The Cassini mission to Saturn will end on September 15th when the spacecraft’s orbit will take it into the gas giant’s atmosphere. This video shows some of the spectacular imagery of the Saturn system sent back by the probe since it went into orbit there in 2004.

** Here is a video clip showing the plume of water vapor emitted at the pole of Saturn’s moon Enceladus: Cassini: The Grand Finale: Last Enceladus Plume Observation

This movie sequence of images is from the last dedicated observation of the Enceladus plume by NASA’s Cassini spacecraft.

The images were obtained over approximately 14 hours as Cassini’s cameras stared at the active, icy moon. The view during the entire sequence is of the moon’s night side, but Cassini’s perspective Enceladus shifts during the sequence. The movie begins with a view of the part of the surface lit by reflected light from Saturn and transitions to completely unilluminated terrain. The exposure time of the images changes about halfway through the sequence, in order to make fainter details visible. (The change also makes background stars become visible.)

The images in this movie sequence were taken on Aug. 28, 2017, using Cassini’s narrow-angle camera. The images were acquired at a distance from Enceladus that changed from 684,000 to 539,000 (1.1 million to 868,000 kilometers). Image scale changes during the sequence, from 4 to 3 miles (7 to 5 kilometers) per pixel.

** Sharpest images yet of Saturn’s rings: Cassini: The Grand Finale: Colorful Structure at Fine Scales

These are the highest-resolution color images of any part of Saturn’s rings, to date, showing a portion of the inner-central part of the planet’s B Ring. The view is a mosaic of two images that show a region that lies between 61,300 and 65,600 miles (98,600 and 105,500 kilometers) from Saturn’s center.

The first image (Figure A, above) is a natural color composite, created using images taken with red, green and blue spectral filters. The pale tan color is generally not perceptible with the naked eye in telescope views, especially given that Saturn has a similar hue.

The material responsible for bestowing this color on the rings—which are mostly water ice and would otherwise appear white—is a matter of intense debate among ring scientists that will hopefully be settled by new in-situ observations before the end of Cassini’s mission.


More about Cassini’s final days and its legacy:

Videos: Cassini and the wonders of Saturn + An overview of the Voyager mission

A video of highlights of the many discoveries and marvelous images made by the Cassini mission to the Saturn system:

Checkout the Cassini: The Grand Finale: Cassini’s ‘Inside-Out’ Rings Movie:

This movie sequence of images from NASA’s Cassini spacecraft offers a unique perspective on Saturn’s ring system. Cassini captured the images from within the gap between the planet and its rings, looking outward as the spacecraft made one of its final dives through the gap as part of the mission’s Grand Finale. Using its wide-angle camera, Cassini took the 21 images in the sequence over a span of about four minutes during its dive through the gap on Aug. 20, 2017. The images have an original size of 512 x 512 pixels; the smaller image size allowed for more images to be taken over the short span of time. [Full caption]
A talk by Alan Cummings, Senior Research Scientist at Caltech and Voyager team member since 1973, about the two Voyager spacecraft and their travels out into interstellar space:

From the caption:

In 1977, NASA’s twin Voyager spacecraft embarked on an incredible journey to the outer planets and beyond. After delivering stunning images of Jupiter, Saturn, Uranus and Neptune, the probes sailed on to study the boundary of our heliosphere, the bubble that encompasses our sun, planets and solar wind. Voyager 1 crossed that frontier in August 2012, becoming the first human-made object in interstellar space, while Voyager 2 is expected to enter the space between the stars in the coming years. This live public talk at NASA’s Jet Propulsion Laboratory in Pasadena, California, revisits highlights of the last 40 years and discuss what may lie ahead for the intrepid Voyagers.

After 40 years, Voyagers 1 and 2 still talk to us from billions of kilometers away

This summer marks the 40th anniversary of the launches of the two Voyager spacecraft, which are still in contact with earth as they head out into interstellar space:

More about the two deep space explorers:

A longer documentary about the Voyager missions:



Video: “A World Unveiled: Cassini at Titan”

The Cassini-Huygens mission ends on September 15th when the Cassini spacecraft will plunge into Saturn’s atmosphere. Looking back on the 13 years of exploring the Saturn system, the discoveries about Titan, on which the Huygens probe landed, were among the richest of the whole program: Cassini: The Grand Finale: Cassini Prepares to Say Goodbye to a True Titan

Saturn’s giant, hazy moon Titan has been essential to NASA’s Cassini mission during its 13 thrilling years of exploration there. Cassini and the European Huygens probe have revealed a fascinating world of lakes and seas, great swaths of dunes, and a complex atmosphere with weather – with intriguing similarities to Earth. Titan has also been an engine for the mission, providing gravity assists that propelled the spacecraft on its adventures around the ringed planet. For more about the Cassini-Huygens mission, visit

Over the course of its 13-year mission at Saturn, Cassini has made 127 close flybys of Titan, with many more-distant observations. Cassini also dropped off the European Space Agency’s Huygens probe, which descended through Titan’s atmosphere to land on the surface in January 2005.

Successes for Cassini during its mission include the revelation that, as researchers had theorized, there were indeed bodies of open liquid hydrocarbons on Titan’s surface. Surprisingly, it turned out Titan’s lakes and seas are confined to the poles, with almost all of the liquid being at northern latitudes in the present epoch. Cassini found that most of Titan has no lakes, with vast stretches of linear dunes closer to the equator similar to those in places like Namibia on Earth. The spacecraft observed giant hydrocarbon clouds hovering over Titan’s poles and bright, feathery ones that drifted across the landscape, dropping methane rain that darkened the surface. There were also indications of an ocean of water beneath the moon’s icy surface.

The instruments on Cassini allowed for seeing Titan in different ways: Cassini: The Grand Finale: Two Titans

These views were obtained with the Cassini spacecraft narrow-angle camera on March 21, 2017. Images taken using red, green and blue spectral filters were combined to create the natural-color view at left. The false-color view at right was made by substituting an infrared image (centered at 938 nanometers) for the red color channel.

These two views of Saturn’s moon Titan exemplify how NASA’s Cassini spacecraft has revealed the surface of this fascinating world. > Full image and caption

More about the final days of Cassini: Cassini: The Grand Finale: Cassini to Begin Final Five Orbits Around Saturn.


Juno: Flyby of Jupiter’s Great Red Spot

The Juno spacecraft made a low altitude flyover of Jupiter’s Great Red Spot this week: NASA’s Juno Spacecraft Completes Flyby over Jupiter’s Great Red Spot. Here are a couple of images made by Citizen Scientists quickly processing the raw images: JunoCam : Processing | Mission Juno .

Great Red Spot [ 060 ] V1  – 2017-07-12 17:09 UT – Credit : NASA / SwRI / MSSS / Gerald Eichstädt / Seán Doran
Sleepy Eye – 2017-07-12 12:00 UT – Credit : Tom Momary © CC NC SA