Monday, June 16, 2008

As The Worlds Turn

As a child, I was fascinated by astronomy, and remain so to this day. I had a telescope from an early age, and enjoyed many nights looking at the night sky through that little 3-inch refractor. In those days of the 1960s, astronomers had the Solar System pretty well defined. It consisted of nine planets, in order from the sun; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto; with various moons, comets and the asteroid belt between the orbits of Mars and Jupiter. Since that time, better telescopes and unmanned probes to the outer solar system have changed the view of our planetary system.

Today, eight planets are recognized, since the discovery of Eris, a world larger than Pluto, gave astronomers reason to reconsider the former 9th planet's status. It turns out that Pluto, smaller than Eris, is just a little larger than a few other newly discovered worlds orbiting the sun. Today, Pluto, Eris, and the former astroid Ceres, are considered "Dwarf Planets". Here are some of the recently discovered worlds circling the Sun.

Some of the most fascinating worlds in the Solar System are the so-called "moons", or natural satellites of the planets orbiting the sun. I say "so-called" because this is the term commonly used, even though there is only one world officially called "The Moon"...Earth's own companion.

Back in the 1960s, there were 31 known moons orbiting the planets. How that number has mushroomed!

Of course the Kuiper Belt, a second, larger, more distant asteroid belt has been discovered. Then there is evidence to support the hypothesis of the existence of the Oort Cloud, home to the comets, and extending a quarter of the way to Proxima Centauri (the nearest star to our own sun).

The more we learn, the more fascinating and complex is this part of the universe we call home.

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