Hubble Takes A Beautiful Portrait Of Saturn

The NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 observed Saturn on June 20, 2019 as the planet made its closest approach to Earth this year, at approximately 845 million mile (1.36 billion km) away. Click the photo for a larger version. NASA, ESA, A. Simon (GSFC), and M.H. Wong (U. of Cal., Berkeley)

Let you eyes soak this one in. I look at Saturn all the time in my telescope. But this image made me stop and stare. It is so rich with detail and has such pleasing colors, it’s a joy to behold.

When we think of the Hubble Space Telescope pictures of galaxies often come to mind, but it’s also used to photograph the planets and other solar system objects on occasion. The detail it can provide is surpassed only by visiting space probes.  And Hubble has an advantage — it can observe the objects over much longer periods of time compared to say a flyby mission. Decades even.

Because Saturn’s axis is tipped, we see different presentations of the rings as the planet cycles around the sun every 29 years. Saturn’s northern hemisphere and the north side (left) of the rings are currently facing Earth. That makes it summer in the planet’s northern hemisphere. Bob King

Saturn’s rings are almost fully tilted toward the Earth. The extra surface reflects extra sunlight, making Saturn brighter to the eye now compared to when we see the rings edge-on. The reason they appear to tip back and forth over Saturn’s 29-year orbit is that the planet’s axis is tipped about 27°, not very different from Earth’s 23.5° tilt. As it orbits, we see different aspects of the rings — the north side, edge-on and then the south side — over the course of one Saturnian year.

Hubble captured this photo of Saturn with its rings almost edgewise on Feb. 24, 2009. Saturn’s largest moon Titan casts a black shadow onto the planet’s north polar hood. You might just be able to see the tiny moon Mimas (just above the ring plane left of center) and its teeny black shadow. NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

When the rings are wide open we get a magnificent view of their bright, icy structure. Hubble 94-inch mirror separates the three main rings visible in amateur telescopes into numerous ringlets and the fainter inner rings. Dutch astronomer Christiaan Huygens first identified the rings in 1655 and thought they were a continuous disk encircling the planet, but nothing of the sort is possible. A solid disk would break into bits as the inner part of the ring, being closer to the planet, would rotate faster than the outer edge. We now know that the rings are made of orbiting chunks and particles of ice and dust.

The age of Saturn’s ring system continues to be debated. Is it young or has it been around since the early days of the solar system? Astronomers hypothesize that the rings formed from the remains of a former satellite destroyed in an impact, but no one really knows for certain.

An artist’s view of Saturn’s rings seen from up close along with an astronaut orbiting above the ring plane. This is a frame from the video Wanderers by Erik Wernquist. Click the link — it’s a beautiful piece.

Another intriguing feature is the long-lasting hexagon-shaped structure circling the planet’s north pole caused by a high-speed jetstream. Four Earths could fit inside it! Other features, however, are not as long-lasting. A large storm in the north polar region spotted by Hubble last year has disappeared. Smaller,  storms, like the little white dot at center-left on the planet’s disk also come and go.

This composite image, taken by the Hubble on June 20, shows the ringed planet Saturn with four of its 62 known moons. NASA, ESA, A. Simon (GSFC) and the OPAL Team

Saturn’s rich palette of brown and yellow clouds arise from summer smog-like hazes, produced when ultraviolet light from the sun interacts with ammonia-ice-rich clouds. The planet’s banded structure is caused by the winds and clouds at different altitudes. Hubble puts it all together for a memorable sight.

** For more about amazing things in outer space — real and imagined — check out my new book titled Urban Legends from Space from AmazonBarnes & Noble and Indiebound  currently available for pre-sale at a nice discount.

3 Responses

  1. Edward M Boll

    A 6 inch scope would show Saturn nicely, with a good look at Titan. Visible tonight about 25 degrees from Jupiter. The 2 becoming very close in 15 months. With the bright Moon, looking for comets is a little impractical now. So, about a mystery? What happened to 168. Comets this week, puts it fading now dimmer than mag 12. But it has not been observed. With a few now brighter than mag 12, that is why I plan on soon making payments on a 10 inch reflector.

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