Hubble’s last portrait of Saturn and its rings

On June 20, 2019, Hubble Space Telescope snapped this beautiful portrait of Saturn and its rings at the ringed planet’s closest approach to Earth. The image was published on September 12, 2019.

Related: 20 best photos of Cassini’s voyage around Saturn

Hubble's Latest Portrait of Saturn and its rings (June 20, 2019)
Saturn’s Rings Shine in Hubble’s Latest Portrait. “Saturn is so beautiful that astronomers cannot resist using the Hubble Space Telescope to take yearly snapshots of the ringed world when it is at its closest distance to Earth.” Image: NASA
This new Hubble Space Telescope view of Saturn, taken in late June of 2019, reveals the giant planet’s iconic rings. Saturn’s amber colors come from summer smog-like hazes, produced in photochemical reactions driven by solar ultraviolet radiation. Below the haze lie clouds of ammonia ice crystals, as well as deeper, unseen lower-level clouds of ammonium hydrosulfide and water.
The planet’s banded structure is caused by winds and clouds at different altitudes. Hubble’s Wide Field Camera 3 observed Saturn on June 20, 2019, as the planet made its closest approach to Earth, at about 845 million miles (1.36 billion km) away.
Hubble images of Saturn (1990, 2019)
Hubble’s first image of Saturn (left), from 1990, versus its most recent, released last week (June 2019, released on September 2019). The telescope is the same, but its instruments have been vastly improved. (Corey S. Powell on Twitter) Five servicing missions (1993, 1997, 1999, 2002, 2009) fixed Hubble’s internal optics and significantly upgraded its capabilities.

Saturn’s rings

Saturn has the most extensive ring system of any planet in the Solar System, and probably in our galaxy Milky Way (maybe with the exception of J1407b, which dubbed as “Saturn on steroids”). That’s why it is unique among the planets – and most people consider Saturn as the most beautiful planet.

The rings of Saturn consist of countless small particles which are made almost entirely of water ice, with a trace component of rocky material. The particles’ size range from micrometers to meters: from too tiny to see to “particles” the size of a bus.

These particles orbit around Saturn, but, interestingly, and interestingly, each ring orbits at a different speed around the planet.

The size of the rings

Saturn by Gordan Ugarkovic
This view of Saturn was created made by the amateur image processor and Cassini fan Gordan Ugarkovic from images obtained on October 10, 2013. It was chosen as NASA’s image of the day for October 17, 2013. You can see the full-resolution image on NASA’s web site.

Saturn’s ring system extends up to 175,000 miles (282,000 kilometers) from the planet. Yet their vertical height is typically about 30 feet (10 meters) in the main rings. So, they form a very thin disk.

The rings are relatively close to each other, with the exception of a gap measuring 2,920 miles (4,700 km) wide. This gap called the Cassini Division and separates Rings A and B.

The rings are named alphabetically in the order they were discovered. The main rings are A, B, and C. Rings D, E, F and G are fainter and more recently discovered.

Starting at Saturn and moving outward, there is the D ring, C ring, B ring, Cassini Division, A ring, F ring, G ring, and finally, the E ring. Much farther out, there is the very faint Phoebe ring in the orbit of Saturn’s moon Phoebe.

Why does Saturn have rings?

Saturn’s rings are one of the great mysteries in space: no one knows for sure why the planet has rings. But scientists have some ideas: they are thought to be pieces of comets, asteroids or shattered moons that broke up before they reached the planet, torn apart by Saturn’s powerful gravity.

Saturn from Cassini, 2016-10-28
Taken on October 28, 2016, it was one of Cassini’s last looks at Saturn and its main rings from a distance (approximately 870,000 miles / 1.4 million kilometers). The planet’s northern hemisphere is seen here at the top. This view looks toward the sunlit side of the rings from about 25 degrees above the ring plane. Images taken with the wide-angle camera using red, green and blue spectral filters were combined to create this color view.

The first person to observe Saturn’s rings

Galileo Galilei was the first person to observe Saturn’s rings in 1610, but he couldn’t understand what they were.

In 1655, the Dutch physicist, mathematician, astronomer, and inventor Christiaan Huygens (14 April 1629 – 8 July 1695) was the first person to describe them as a disk surrounding Saturn.

Huygens proposed that Saturn was surrounded by a solid ring: “a thin, flat ring, nowhere touching, and inclined to the ecliptic.” Using a 50 power refracting telescope that he designed himself, Huygens also discovered the first of Saturn’s moons, Titan.

The most detailed images of Saturn’s rings ever taken. NASA’s Cassini spacecraft is on a daredevil mission that is taking it closer to the planet Saturn than it has been in over a decade. In December, the spacecraft skimmed by Saturn’s outer rings, snapping some of the most detailed images we have ever seen.
This Hubble time-lapse movie shows the orbits of some of Saturn’s icy moons as they circle the planet over an 18-hour period. The video is composed of 33 Hubble snapshots of the planet, taken June 19 to 20, 2019, by the Wide Field Camera 3. The closer the moon is to Saturn, the faster it orbits, according to the laws of gravity.

Sources

“Saturn’s Rings Shine in Hubble’s Latest Portrait” on NASA.gov
“Why does Saturn has rings?” on NASA Spaceplace website
Rings of Saturn on Wikipedia
What are Saturn’s rings made of? on How Stuff Works website
Saturn on NASA Solar System Exploration website

M. Özgür Nevres

I am a software developer, an ex-road racing cyclist, and a science enthusiast. Also an animal lover! I write about the planet Earth and science on this website, ourplnt.com. You can check out my social media profiles by clicking on their icons.

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