The Solar System
Part II
Previously, we began our exploration of the Solar System. We learned about the Sun and inner planets.
Let's continue our exploration with the outer planets.
Distant relations
Moving away from the Sun, one would first encounter a region with an increased number of asteroids called, no surprise, the “asteroid belt.” Beyond this are the “gas giants.” These planets have a solid core, but the core is surrounded by a vast atmosphere that makes up most of the volume.
Jupiter
Jupiter is the largest planet in the solar system.
How big is Jupiter? Consider the famous red spot on the right side of the picture above. The red spot is, in fact, a large storm, big enough to contain at least two Earths. The size of this planet can be appreciated by looking at the picture of IO, one of its many moons, shown below. In this photo, Jupiter fills the background.
Jupiter has a ring that is too small to be seen from Earth.
A mosaic of Jupiter's rings taken by the Galileo spacecraft, taken when the Sun was behind Jupiter.
Moving away from the Sun and its warming influence means the planets will be getting colder. In the case of Jupiter, this means a temperature of about 150º F below zero. Jupiter's atmosphere is different from Earth's in a couple of important ways.
On the Earth, the average temperature depends on where you are – warmer near the equator and colder near the poles. However, Jupiter's atmosphere is warmed mostly by its own heat rather than the Sun. So the temperature depends more on how far into the planet one goes.
Earth's atmosphere is perfect for breathing. On Jupiter, the atmosphere is mostly Hydrogen and Helium with some methane and ammonia (stinky stuff!).
Number of moons: 79
Saturn
Though not as big as Jupiter, Saturn is perhaps the most famous planet with its large rings.
The rings are thin, made mostly of ice. I was told by someone who knows more about Saturn than I, that there are six known rings, labeled A – F. The atmosphere of Saturn itself, like the other gas giants, is mostly made of Hydrogen and Helium gas.
Average temperature: about 180º F below zero
Number of moons: 82
Uranus
Uranus is the most distant planet known to the ancients.
An oddity about Uranus is that its axis of rotation points almost directly to the Sun. What this means is, although it only takes 17 hours to turn about its axis, a spot on Uranus spends half the year in daylight and the other in the night.
Number of moons: 27
Neptune
The planet Neptune was the first discovered in more recent times. Galileo almost discovered it, but mistook it for a star. Its discovery would wait until the 1800s when its final discovery was prompted by observations that Uranus wobbled about its orbit a bit. The gravity from some unseen object was responsible. Further observation revealed the planet Neptune.
Number of moons: 14
Pluto
Once the ninth planet, in recent times its classification was downgraded to a “minor planet” or “dwarf planet” – though in my book I will always call it a planet.
Like Neptune, Pluto's discovery was prompted by noticing how the other planet's paths went off their expected path – something was pulling it off course. Hence, Pluto's discovery.
Number of moons: 5
The planets, moons and the Sun that drives everything not only make up the part of the Cosmos in which we live, but are also a beautiful,l cosmic family of jewels. A wonder to behold!
Great Music
The Planets, Gustav Holst
The Planet Suite is a collection of classical pieces featuring all the planets known by the composer at the time (1916). The inspiration for the mood and theme for each based on their astrological significance to Holst.
Mars, the Bringer of War
Venus, the Bringer of Peace
Mercury, the Winged Messenger
Jupiter, the Bringer of Jollity
Saturn, the Bringer of Old Age
Uranus, the Magician
Neptune, the Mystic
My favorite of these pieces is Mars. It is more dramatic in an invasion from Mars sort of way. You can listen to any of these songs here. Listen to the different songs and see which ones you like the best.
On the web
Planet Song for Song/Solar System Song
This fun song introduces the planets in order and gives a little something about each.
Universe Sandbox 2 - Full Jovian System in action
This video shows a simulation of the Jovian system – Jupiter and its moons. No sound, but you still get a good visual of how this planet and moons move.
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