saturn

May 2014 guide to the five visible planets

  • May 7, 2014

saturn-eso-300x193May 2014 is Saturn’s month. We pass between Saturn and the sun on May 10, bringing the planet closest for this year. May is great for other planets, too! Charts, pics, info here.

Jupiter and Mars both pop into view as soon as darkness falls on these May 2014 evenings. Both are very, very bright. It’s not likely that you’ll mistake one planet for the other. They are in different parts of the sky, and exhibit different colors. Jupiter appears cream-colored and Mars reddish. At early evening, golden Saturn rises over southeast horizon, and though not as bright as Jupiter or Mars, its brilliance is on par with the sky’s brightest stars. And, by rights, this is Saturn’s month. The ringed planet is closest to us in May 2014 for this year.2014-may-2-text3-corvus-spica-ecliptic-night-sky-chart-300x300

Saturn is the planet to watch in May 2014. As seen from the whole Earth, Saturn sits low in southeast at nightfall and early evening. Earth in its smaller, faster orbit passes between the sun and Saturn on May 10, bringing the planet opposite the sun in our sky (opposition). In 2014, Saturn shines in front of the constellation Libra, making a triangle with the constellation’s two brightest stars, Zubenelgenubi and Zubeneschamali. Look for the almost full moon to couple up with Saturn on the night of May 13!

Mercury will present its best evening apparition of the year for the Northern Hemisphere in May 2014. This month, you almost certainly need to be in the Northern Hemisphere or southern tropics for any chance of seeing Mercury, which is the innermost planet of the solar system and which, therefore, stays near the sun in our sky. Northerly latitudes will see Mercury starting the second week of May. Mercury will reach its greatest eastern elongation – greatest angular distance from the setting sun on our sky’s dome – on May 25. Look for the slender lunar crescent near Mercury after sunset on May 30.

Venus, the sky’s brightest planet is still prominent in the eastern predawn/dawn sky throughout May. In fact, dazzling Venus will remain the most brilliant star like object in the morning sky until late October 2014, at which time it will shift over into the evening sky. The lovely waning crescent moon swings close to Venus on May 25.

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Is Saturn making a new moon?

  • April 16, 2014

A small icy object within the rings of Saturn might be a brand new moon in the process of being born.

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NASA’s Cassini spacecraft has documented the formation of a small icy object within the rings of Saturn that may be a new moon, and may also provide clues to the formation of the planet’s known moons.

Images taken with Cassini’s narrow angle camera on April 15, 2013, show disturbances at the very edge of Saturn’s A ring — the outermost of the planet’s large, bright rings. One of these disturbances is an arc about 20 percent brighter than its surroundings, 750 miles (1,200 kilometers) long and 6 miles (10 kilometers) wide. Scientists also found unusual protuberances in the usually smooth profile at the ring’s edge. Scientists believe the arc and protuberances are caused by the gravitational effects of a nearby object. Details of the observations were published online today (April 14, 2014) by the journal Icarus.

The object is not expected to grow any larger, and may even be falling apart. But the process of its formation and outward movement aids in our understanding of how Saturn’s icy moons, including the cloud-wrapped Titan and ocean-holding Enceladus, may have formed in more massive rings long ago. It also provides insight into how Earth and other planets in our solar system may have formed and migrated away from our star, the sun.

“We have not seen anything like this before,” said Carl Murray of Queen Mary University of London, the report’s lead author. “We may be looking at the act of birth, where this object is just leaving the rings and heading off to be a moon in its own right.”

The object, informally named Peggy, is too small to be seen in images so far. Scientists estimate it is probably no more than about a half mile (about a kilometer) in diameter. Saturn’s icy moons range in size depending on their proximity to the planet — the farther from the planet, the larger. And many of Saturn’s moons are composed primarily of ice, as are the particles that form Saturn’s rings. Based on these facts, and other indicators, researchers recently proposed that the icy moons formed from ring particles and then moved outward, away from the planet, merging with other moons on the way.

“Witnessing the possible birth of a tiny moon is an exciting, unexpected event,” said Cassini Project Scientist Linda Spilker, of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. According to Spilker, Cassini’s orbit will move closer to the outer edge of the A ring in late 2016 and provide an opportunity to study Peggy in more detail and perhaps even image it.

It is possible the process of moon formation in Saturn’s rings has ended with Peggy, as Saturn’s rings now are, in all likelihood, too depleted to make more moons. Because they may not observe this process again, Murray and his colleagues are wringing from the observations all they can learn.

“The theory holds that Saturn long ago had a much more massive ring system capable of giving birth to larger moons,” Murray said. “As the moons formed near the edge, they depleted the rings and evolved, so the ones that formed earliest are the largest and the farthest out.”

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, manages the mission for NASA’s Science Mission Directorate in Washington.

Via NASA