The Planets

Pttm, Going Postal

To give an idea of the size of Saturn, you can see it here compared to some of our other planets.  Not as big as Jupiter but you could still fit 764 Earths into it.

Pttm, Going Postal
Earth’s relative size compared to Jupiter, Saturn, Uranus and Neptune

The Prologue:

Throughout this series, I would like to give a huge H/T to NASA..  I have used other sources as well, such as  Space.com  and EarthSky which is a great site for showing you where to look.

Part 6 – Saturn

Adorned with thousands of beautiful ringlets, Saturn is unique among the planets.   All four gas giant planets (Jupiter, Uranus and Neptune being the others) have rings — made of chunks of ice and rock — but none are as spectacular or as complicated as Saturn’s.  Like the other gas giants, Saturn is mostly a massive ball of hydrogen and helium.

It is named for the Roman god Saturnus, and was known to the Greeks as Cronus.

Distance from the sun: About 900 million miles, nearly 10 times as far as Earth is from the sun.

Year: 29.5 Earth years.

Day: About 10.7 Earth hours.

Diameter: About 72,000 miles, nine times the size of Earth.

Effective temperature: – 288 degrees Fahrenheit.  About -142 degrees c

Atmosphere: Hydrogen, helium.

Saturn has 62 Moons, the largest being Titan, Enceladus, Lapetus & Rhea.  It also has 88 “moonlets” discoverd so far.

First Record: 8th century BC by Assyrians

Missions include Pioneer 10, 11 and Voyager 1 and 2 which were all fly-by’s.  The Galileo mission studied the planet and its moons, as well as several other Solar System bodies.  It consisted of an orbiter and entry probe. Launched on October 18, 1989, carried by Space Shuttle Atlantis, on the STS-34 mission. Galileo arrived at Jupiter on the 7th December 1995, and became the first spacecraft to orbit Jupiter.  It launched the first probe into Jupiter, directly measuring its atmosphere.  In 1994 Galileo also observed Comet Shoemaker–Levy 9‘s collision with Jupiter.  A magnificent sight indeed.

Saturn’s upper atmosphere is divided into bands of clouds.  The top layers are mostly ammonia ice.  Below them, the clouds are largely water ice.  Below are layers of cold hydrogen and sulfur ice mixtures.  Hydrogen 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 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 has the most extensive rings in the solar system.  The Saturnian rings are made mostly of chunks of ice and small amounts of carbonaceous dust. The rings stretch out more than 120,700 km from the planet, but are are amazingly thin: only about 20 meters thick.

The most recent mission was Cassini,  the 2017 orbital highlights are here:   https://www.nasa.gov/mission_pages/cassini/timeline/index.html

On the 15th September 2017, during Orbit 293 it completed an atmospheric entry into the planet.

The other part of the Cassini mission was The European Space Agency’s Huygens Probe which descended upon Titan.  It was a unique, advanced spacecraft and a crucial part of the overall Cassini mission to explore Saturn.  The probe was about 9 feet wide (2.7 meters) and weighed roughly 700 pounds (318 kilograms). It was built like a shellfish: a hard shell protected its delicate interior from high temperatures during the a two hour and 27 minute descent through the atmosphere of Saturn’s giant moon Titan.  You can see more on this mission here:  https://saturn.jpl.nasa.gov/mission/spacecraft/huygens-probe/

You cannot do an article on Saturn without explaining a bit more about those magnificent rings.

The rings were discovered by Galileo Galilei 1610 who observed them with a telescope.  The first ‘up close’ view of the rings were by Pioneer 11 spacecraft which flew by Saturn on the 1st September 1971.

Saturn’s rings are made up of billions of particles that range in size from tiny dust grains to to objects as large as mountains. These are made up of chunks of ice and rock, believed to have come from asteroids comets or even moons, that broke apart before they reached the planet.

Saturn’s rings are divided into 7 groups, named alphabetically in the order of their discovery (Outwards from Saturn; D, C, B, A, F, G and E). The F ring is kept in place by two of Saturn’s moons, Prometheus and Pandora, these are referred to as ‘shepherd moons’.  Other satellites are responsible for creating divisions in the rings as well as shepherding them.  Here’s a picture of the thin sliver of Saturn’s moon Prometheus which lurks near ghostly structures in Saturn’s narrow F ring in this view from NASA’s Cassini spacecraft.  Many of the narrow ring’s faint and wispy features result from its gravitational interactions with a moonlet Prometheus (86 kilometers, or 53 miles across).

Pttm, Going Postal
Prometheus and Saturn’s rings

Where to find it:

February guide to the bright planets

At the start of 2018 Saturn is very close to the sun, so is very hard or more likely impossible to see.  It will be very visible from mid July 2018.  The site below shows you where you can see the planets from London.

https://www.timeanddate.com/astronomy/night/uk/london

Check the above link regularly to see where planets and stars can currently be seen.

© Phil the test manager 2018