Tuesday, April 15, 2014

62 moons or is it 63? – Saturn ring gives birth to ‘Peggy'

Saturn may be a proud papa. The Cassini spacecraft has documented the formation of a small icy object within the rings of Saturn. This object or new moon about .8 kilometers in diameter has been dubbed unofficially ‘Peggy’.

To better understand this possible new moon first it is necessary to look deeper into Saturn’s rings. The rings around Saturn are the most extensive seen in this solar system. They may look like rings, but in actuality they are countless small particles in sizes the run from specks of dust to meters all orbiting Saturn. The particles are made up of mostly ice with a rock component. We are currently clueless as to when they first formed. Some say there is evidence which point to recent formation others point to when the solar system first began.

While Saturn’s rings appear to be solid disks in actuality as previously said before they are made up of particles but also have at least 2 gaps, areas to date which are unexplained. Additionally they have two known moons within their ranks. Even cooler, the rings have names. There’s the Titan Ringlet and the G ring for instance and many, many more. The rings extend outward from about 7000 kilometers from slightly above Saturn’s equator and end near to 80,000 kilometers from it. It is thought to be the gravitational effects and orbital resonances are highly responsible for maintaining both the rings and the gaps.

There is a long history of fascination with the rings starting with Christiaan Huygens the first to suggest that Saturn was surrounded by a ring. Robert Hooke followed, Giovanni Domenico Cassini as well and Pierre-Simon LaPlace who thought the rings were solid. In 1859 James Clerk Maxwell proved that they were comprised of small particles. Many others followed each putting in his or her ten cents but Saturn’s intricate structure was best understood when it was visited by both of the Voyager spacecraft.

The picture below was taken by Cassini and shows unusual protuberances in the usually smooth profile at the ring's edge. It was taken April 15, last year and shows disturbances at the very edge of Saturn's A ring - the outermost of the planet's large, bright rings.


When speaking more generally of a planetary disk (it is said to be an accretion disk from stellar debris that returns to the disruption sit and rotates, spreading out to various radii to conserve angular momentum) satellites (or moons) form and migrate away. This happens especially when the spreading of the solar system is slow. So planets where the spreading is slow such as Saturn have 62 now 63 moons whereas when the spreading is faster such as say Earth or Pluto less satellites are incurred.


Obviously this description has holes in it mostly due to our limited but growing understanding of both the rings and the birthing process in this case. However our knowledge just got a boost up as Saturn welcomed Peggy into the Universe.

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