Vertical structures, among the tallest seen in Saturn’s main rings, rise abruptly from the edge of Saturn’s B ring to cast long shadows on the ring in this image taken by NASA’s Cassini spacecraft two weeks before the planet’s August 2009 equinox.
Possible variations in chemical composition from one part of Saturn’s ring system to another are visible in this Voyager 2 picture as subtle color variations that can be recorded with special computer-processing techniques.
In 40 million years, Mars may have a ring (and one fewer moon)
Nothing lasts forever – especially Phobos, one of the two small moons orbiting Mars. The moonlet is spiraling closer and closer to the Red Planet on its way toward an inevitable collision with its host. But a new study suggests that pieces of Phobos will get a second life as a ring around the rocky planet.
A moon – or moonlet – in orbit around a planet has three possible destinies. If it is just the right distance from its host, it will stay in orbit indefinitely. If it’s beyond that point of equilibrium, it will slowly drift away. (This is the situation with the moon; as it gradually pulls away from Earth, its orbit is growing by about 1.5 inches per year.) And if a moon starts out on the too-close side, its orbit will keep shrinking until there is no distance left between it and its host planet.
The Martian ring will last for at least 1 million years – and perhaps for as long as 100 million years, according to the study.
The rest of Phobos will probably remain intact, until it hits the Martian surface. But it won’t be a direct impact; instead, the moonlet’s remains will strike at an oblique angle, skipping along the surface like a smooth stone on a calm lake.
This has probably happened before – scientists believe a group of elliptical craters on the Martian surface were caused by a small moon that skidded to its demise. (If this were to happen on Earth, our planet’s greater mass would produce a crash as big as the one that wiped out the dinosaurs, the researchers noted as an aside.)
Saturn’s rings display their subtle colors in this view captured on Aug. 22, 2009, by NASA’s Cassini spacecraft. The particles that make up the rings range in size from smaller than a grain of sand to as large as mountains, and are mostly made of water ice. The exact nature of the material responsible for bestowing color on the rings remains a matter of intense debate among scientists.
Saturn’s moon Dione drifts before the planet’s rings, seen here almost edge on. For all their immense width, the rings are relatively paper-thin, about 30 feet (10 meters) in most places. For its part, Dione is about 698 miles (1,123 kilometers) across.
Saturn is sometimes called “The Jewel of the Solar System.” It is a planet that is nothing like our own. Humans have been gazing up at Saturn for a long time. They have been wondering about it for thousands of years.
Here are some fun facts about the Ringed Planet.
Saturn is huge. It is the second largest planet in our Solar System. Jupiter is the only planet that is bigger.
The rings are huge but thin. The main rings could almost go from Earth to the moon. Yet, they are less than a kilometer thick.
Four spacecraft have visited Saturn: Pioneer 11, Voyager 1 and 2, and the Cassini-Huygens mission have all studied the planet. Cassini continues to orbit Saturn, sending back a wealth of data about the planet, its moons, and rings.
Saturn has oval-shaped storms similar to Jupiter’s: The region around its north pole has a hexagonal-shaped pattern of clouds. Scientists think this may be a wave pattern in the upper clouds. The planet also has a vortex over its south pole that resembles a hurricane-like storm.
Saturn is made mostly of hydrogen and helium: It exists in layers that get denser farther into the planet. Eventually, deep inside, the hydrogen becomes metallic. At the core lies a hot interior.
Saturn has 62 moons: Some of these are large, like Titan, the second largest moon in the Solar System. But most are tiny – just a few km across, and they have no official names. In fact, the last few were discovered by NASA’s Cassini orbiter just a few years ago. More will probably be discovered in the coming years.
Saturn orbits the Sun once every 29.4 Earth years: Its slow movement against the backdrop of stars earned it the nickname of “Lubadsagush” from the ancient Assyrians. The name means “oldest of the old”.
In Saturn there is aurora: Photographic composition made by the Hubble Space Telescope showing the occurrence of aurora in the southern hemisphere of Saturn at intervals of two days.The aurora is visible only in the ultraviolet.
Saturn spins on its axis very fast. A day on Saturn is 10 hours and 14 minutes.
You can see Saturn with your own eyes: Saturn appears as one of the 5 planets visible with the unaided eye. If Saturn is in the sky at night, you can head outside and see it. To see the rings and the ball of the planet itself, you’ll want to peer through a telescope. But you can amaze your friends and family by pointing out that bright star in the sky, and let them know they’re looking at Saturn.
The outermost ring shown here is Saturn’s E ring, the core of which is situated about 149,000 miles (240,000 kilometers) from Saturn. The geysers erupting from the south polar terrain of the moon Enceladus supply the fine icy particles that comprise the E ring; diffraction by sunlight gives the ring its blue color.