Astrophile: Saturn's egg moon Methone is made of fluff - space - 17 May 2013. Astrophile is our weekly column on curious cosmic objects, from the solar system to the far reaches of the multiverse Object: Oval moon MethoneLocation: Saturn's rings Out among Saturn's menagerie of moons, a shiny white egg rests in a nest of ice crystals. Named Methone, this small, oval moon was seen in close-up for the first time last year by NASA's Cassini spacecraft. Methone is utterly unlike the other small balls of ice and rock that dot the solar system, which are deeply scarred by impacts.
Instead it is smooth, with not a hill or pockmark in sight. Objects in our solar system have been battered by asteroids and comets for billions of years, but planets and big moons have ways of smoothing themselves out. Small moons, though, are geologically inactive and airless, so are unable to erase the damage. Clutch of lunar eggs In fact, this 5-kilometre-wide moon is one of a clutch of space eggs, all orbiting Saturn in the same region between the larger moons Mimas and Enceladus. . Image of the Day --NASA Finds Vast River System on Saturn's Moon Titan. Titan has been considered a “unique world in the solar system” since 1908 when, the Spanish astronomer, José Comas y Solá, discovered that it had an atmosphere, something non-existent on other moons.
It seems perfectly appropriate that one of the prime candidates for life in our solar system, Saturn's largest moon, should have surface lakes, lightning, shorelines, relatively thick nitrogen atmosphere, seasons, and now, a vast river system. "Though there are some short, local meanders, the relative straightness of the river valley suggests it follows the trace of at least one fault, similar to other large rivers running into the southern margin of this same Titan sea," said Jani Radebaugh, a Cassini radar team associate at Brigham Young University, Provo, Utah.
"Such faults - fractures in Titan's bedrock -- may not imply plate tectonics, like on Earth, but still lead to the opening of basins and perhaps to the formation of the giant seas themselves. " mage credit: NASA/JPL-Caltech/ASI. Cassini detects hint of fresh air at Dione | Popular Mechanics. Nasa's Cassini spacecraft has "sniffed" molecular oxygen ions around Saturn's icy moon Dione for the first time, confirming the presence of a very tenuous atmosphere.
The oxygen ions are quite sparse – one for every 11 cubic centimetres of space or about 90 000 per cubic metre – show that Dione has an extremely thin neutral atmosphere. At the Dione surface, this atmosphere would only be as dense as Earth's atmosphere 480 kilometres above the surface. The detection of this faint atmosphere, known as an exosphere, is described in a recent issue of the journal Geophysical Research Letters.
"We now know that Dione, in addition to Saturn's rings and the moon Rhea, is a source of oxygen molecules," said Robert Tokar, a Cassini team member based at Los Alamos National Laboratory and the lead author of the paper. "This shows that molecular oxygen is actually common in the Saturn system and reinforces that it can come from a process that doesn't involve life. " Rings. Rings Beautiful, glamorous and mysterious, Saturn's rings are among the most recognizable features in the solar system. They spread over hundreds of thousands of kilometers, yet they are extremely thin – perhaps only 10 meters (about 30 feet) thick.
The rings consist of billions of individual particles of mostly water ice which create waves, wakes and other structures. Named alphabetically in order of their discovery, the order of the main rings outward from Saturn is D, C, B, A, F, G and E. Scientists still aren't sure exactly how old the rings are. Whenever they first formed, it is clear that the rings we observe today were not all created in exactly the same way. The spacecraft began returning valuable information about the rings even before it slipped into Saturn orbit in July 2004.
"The images found evidence for new processes whereby particle sticking and self gravity interact to form structures never seen before," explains Dr. Magnetosphere. Magnetosphere Forces deep inside Saturn create a giant magnetic bubble around the planet, called the magnetosphere, which exerts a powerful influence on particles that float through space near the planet. Saturn's magnetic field creates this bubble as material cycles deep within the planet's fluid interior. In a similar way, Earth's magnetic field creates a much smaller magnetosphere that protects us from harmful particles emitted by the sun and other space phenomena. Outside Saturn's magnetosphere, a million-mile-per-hour gale of particles from the sun, called the solar wind, spreads out through the Solar System. When the solar wind encounters Saturn's magnetosphere, it streams around it, like a stream around a rock.
Saturn's magnetic field has north and south poles, like those on a bar magnet, and the field rotates with the planet. Saturn's Moons. Saturn's Moons The dozens of icy moons orbiting Saturn vary drastically in shape, size, surface age and origin. Some of these worlds have hard, rough surfaces, while others are porous bodies coated in a fine blanket of icy particles. All have greater or smaller numbers of craters, and many have ridges and valleys.
Some, like Dione and Tethys, show evidence of tectonic activity, where forces from within ripped apart their surfaces. Many, like Rhea and Tethys, appear to have formed billions of years ago, while others, like Janus and Epimetheus, could have originally been part of larger bodies that broke up. The study and comparison of these moons tells us a great deal about the history of the Saturn System and of the solar system at large. To date, 53 moons have been officially named. Astronomers continue to find new small moons orbiting Saturn, using both ground-based observatories and Cassini's own imaging cameras. Diversity of Worlds The moons of Saturn are a diverse collection. About Saturn & Its Moons. Introduction On June 30, 2004, the Cassini spacecraft entered orbit around Saturn to begin the first in-depth, up-close study of the ringed planet and its domain. As expected, the Saturn System has provided an incredible wealth of opportunities for exploration and discovery.
With its initial four-year tour of the Saturn system complete as well as an initial two-year extended mission called the Cassini Equinox Mission, the spacecraft is conducting a second extended mission called the Cassini Solstice Mission. "We're looking at a string of remarkable discoveries -- about Saturn's magnificent rings, its amazing moons, its dynamic magnetosphere and about Titan's surface and atmosphere," says Dr. Cassini's observations of Saturn's largest moon, Titan, have given scientists a glimpse of what Earth might have been like before life evolved. The spray of icy particles from the surface jets collectively forms a towering plume three times taller than the width of Enceladus. Science Objectives. Saturn 'burps' after large storm. Nasa’s Cassini spacecraft has tracked the aftermath of a rare massive storm on Saturn. Data reveal record-setting disturbances in the planet’s upper atmosphere long after the visible signs of the storm abated, in addition to an indication the storm was more forceful than scientists previously thought.
Data from Cassini’s composite infrared spectrometer (CIRS) instrument revealed the storm’s powerful discharge sent the temperature in Saturn’s stratosphere soaring 66 degrees Celsius above normal. At the same time, researchers at Nasa’s Goddard Space Flight Centre detected a huge increase in the amount of ethylene gas, the origin of which is a mystery. Ethylene, an odourless, colourless gas, isn’t typically observed on Saturn. On Earth, it is created by natural and man-made sources. Goddard scientists describe the unprecedented belch of energy in a paper to be published in the 20 November issue of the Astrophysical Journal. Video credit: Nasa’s Goddard Space Flight Centre. Plume Zoom. Flying over Enceladus' southern plumes (click to play) Check this piece of coolness out… it’s an animation made of 30 frames of raw image data captured by Cassini during its August 13th flyby of Enceladus. It shows the little moon’s signature ice plumes erupting from fissures in the surface of its south pole as the spacecraft approaches.
Neato!!! Enceladus' Icy Geysers I saw it on The Boston Globe’s September 15th Big Picture post which featured a bunch of great images from current space science missions, but I haven’t found out yet where the original animation was published. (The credit is Space Science Institute but I don’t see it on the CICLOPS site.) (If it’s not animating just give it a click. :) ) Image: NASA/JPL/Space Science Institute Like this post? Like this: Like Loading... Salt in Enceladus geyser points to liquid ocean - space - 29 April 2009. THE ice plumes that bloom above Saturn's icy moon Enceladus are almost certainly rooted in a subsurface sea of liquid water.
The Cassini spacecraft flew through a plume on 9 October 2008 and measured the molecular weight of chemicals in the ice. Frank Postberg of the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, and colleagues, found traces of sodium in the form of salt and sodium bicarbonate. The chemicals would have originated in the rocky core of Enceladus, so to reach a plume they must have leached from the core via liquid water.
Observations from Earth in 2007 spotted no sign of sodium, casting doubt on such a subsurface sea. Although the salt could have been leached out by an ancient ocean which since froze solid, that freezing process would concentrate most of the salt very far from the surface of the moon's ice, ... Hot Cyclones Churn At Both Ends Of Saturn. Despite more than a decade of winter darkness, Saturn's north pole is home to an unexpected hot spot remarkably similar to one at the planet's sunny south pole. The source of its heat is a mystery. Now, the first detailed views of the gas giant's high latitudes from the Cassini spacecraft reveal a matched set of hot cyclonic vortices, one at each pole.
While scientists already knew about the hot spot at Saturn's south pole from previous observations by the W. M. Keck Observatory in Hawaii, the north pole vortex was a surprise. "We had speculated that the south pole hot spot was connected to the southern, sunlit conditions," said Glenn Orton, a senior research scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and co-investigator on Cassini's composite infrared spectrometer. The infrared data show that the shadowed north pole vortex shares much the same structure and temperature as the one at the sunny south pole. Winter lasts about 15 years on Saturn. Oxygen detected on Saturn's moon Rhea | Science. A spacecraft has tasted oxygen in the atmosphere of another world for the first time while flying low over Saturn's icy moon, Rhea.
Nasa's Cassini probe scooped oxygen from the thin atmosphere of the planet's moon while passing overhead at an altitude of 97km in March this year. Until now, wisps of oxygen have only been detected on planets and their moons indirectly, using the Hubble space telescope and other major facilities. Instruments aboard Cassini revealed an extremely thin oxygen and carbon dioxide atmosphere that is sustained by high-energy particles slamming into the moon's surface and kicking up atoms, molecules and ions.
Astronomers have counted 62 moons orbiting Saturn. At 1500km wide, Rhea is the second largest and is thought to be made almost entirely of ice. "This really is the first time that we've seen oxygen directly in the atmosphere of another world," said Andrew Coates, at UCL's Mullard Space Science Laboratory, a co-author of the study published in the journal Science. Two Moons Passing in the Night - Image of the Day - Images. Saturn's Moon Phoebe - Solar System Reference Library. Saturn’s moon Phoebe — Phoebe is the outermost of Saturn’s known moons. Phoebe is almost 4 times more distant from Saturn than its nearest neighbor (Iapetus).
It was discovered by William Henry Pickering in 1898. Most of Saturn’s moons have very bright surfaces, but Phoebe’s albedo is very low (.06), as dark as lampblack. All of Saturn’s moons except for Phoebe and Iapetus orbit very nearly in the plane of Saturn’s equator. Phoebe’s orbit is retrograde, inclined almost 175, and is highly eccentric. The plane of its orbit is much closer to the solar system’s ecliptic than it is to Saturn’s.
Phoebe is also unusual in that it does not rotate synchronously as all the other moons of Saturn except Hyperion do. All this suggests that it may be a captured asteroid with a composition unmodified since the time it was formed in the outer Solar System. Since they are so small they never heated up sufficiently to change chemical composition. Discovery Orbital characteristics Physical characteristics. Possible Subsurface Ocean Beneath Saturn Moon Dione - Space News. May 30, 2013 Image Credit: The Cassini spacecraft looks down, almost directly at the north pole of Dione. The feature just left of the terminator at bottom is Janiculum Dorsa, a long, roughly north-south trending ridge. Credit: NASA/JPL/Space Science Institute Brett Smith for redOrbit.com – Your Universe Online Once considered to be an afterthought when it came to Saturn´s moons, scientists now believe Dione likely had an active geological history after analyzing data sent back from NASA´s Cassini spacecraft.
“A picture is emerging that suggests Dione could be a fossil of the wondrous activity Cassini discovered spraying from Saturn’s geyser moon Enceladus or perhaps a weaker copycat Enceladus,” said Cassini team leader Bonnie Buratti of NASA’s Jet Propulsion Laboratory in Pasadena, California. Cassini´s images suggest that Dione could join Saturn’s other moons that are believed to have subsurface activity, Enceladus and Titan. Source: Brett Smith for redOrbit.com - Your Universe Online. Saturn may have snagged Pluto's cousin, turned it into a moon. Saturn's moon Phoebe might be a planetesimal—a remnant of the rocky building blocks of the planets in our Solar System. A new study by Julie C.
Castillo-Rogez et al. from Cassini spacecraft data indicates that Phoebe dates back to the very earliest days of the Solar System. Based on surface features and evidence that the moon is significantly more dense than the larger Saturnian satellites, the astronomers argue that Phoebe likely formed much farther from the Sun then fell inward, where it was snagged by Saturn's gravity. Using detailed observations from Cassini and Earth-based telescopes, in combination with detailed computer simulations, Castillo-Rogez et al. determined that Phoebe began as a spherical body. Phoebe's orbit is retrograde, meaning it circles in the opposite direction to Saturn's other moons, as well as the planet's rotation. While Phoebe is obviously not a smooth sphere, it's also not as potato-like as many other moons of similar size.
Strongest evidence yet indicates Enceladus hiding saltwater ocean. Saturn's Moons - Images. Saturn's Shockwaves Reach Supernova Force. SaturnEclipsesTheSun. Pac-Man Seen Near Saturn - Space News. "Saturn's Ring System Rains Water into Atmosphere" --(Featured News Story) Saturn's largest moon was once a titanic snowball - space - 18 June 2014.