Friday, September 01, 2006

 

How Many Planets Are There?

"When I consider thy heavens, the work of thy fingers, the moon and the stars, which thou hast ordained; What is man, that thou art mindful of him? and the son of man, that thou visitest him? (Psalm 8:3-4)

When I was in school, I learned, as we all did, that in about 1930, the ninth know planet of our solar system was discovered: Pluto! Well, this is "the rest of the story," so far! A few years ago a tenth planet was discovered. It has been unofficially named Xena. And its status is still unofficial too. Xena, pictured above, is 96 astronomical units away. (1 AU = the distance between Earth and the Sun) The "star" in the picture is what the sun looks like from Xena. Xena has an elliptical orbit and will eventually come to within 38 AU. But one orbit takes 560 years. Pluto also has an elliptical orbit and can be as much as 50 AU away or somewhat closer, depending where it is in its 249 year orbit. So Xena crosses Pluto's path every now and then. And Pluto crosses the path of Uranus too. Both planets are quite small, about one fifth the size of mother Earth.

So, are Xena and Pluto planets? Thats the big question. The discovers of Xena want to make it the 10th (or 12th) planet. But, as you may have heard, Pluto has just been officilally downgraded from a planet to whatever! Why? Its too small to be considered a planet. So, I assume, there goes Xena's hopes for stardom, or should I say "planetdom!" So, all hopes aside, there are only 8 official planets, not 9 or 10 or more.

To me here's the irony! The word planet means "wanterer." Xena and Pluto are the only planets with wandering (elliptical) orbits. And we can't call them wanderers!

UPDATE: Ron just mentioned to me that there are some 12 planets. How many? A moon and an asteriod have been considered planets by some astronomers. The answer to this question comes down to definitions, and its been a hot debade among astronomers. The biggest issue is size. There are now some fifty known space objects that could possibly be considered planets. But a decision, it seems, has been made. Pluto and all smaller objects have been down-graded! There are eight planets and at least four dwarf planets. More, I assume, may be found in the future.

God has created an amazing Universe with millions of Galaxy clusters (only three discinct sizes, by the way), with millions of stars in each Galaxy, and here we are on a mid-sized planet, just the right distance from a rather small star we call the Sun, in a rather safe place between a couple of the Milky Way Galaxy's arms.(See "Faith and Science" below.) And we are miniscule creatures on this planet. Yet God takes a special interest in us and loves us dearly. May we respond to Him in like manner.

Comments:
This is very interesting to me now.When I was in school I had little interest in it but now is different.Thanks for shedding some light on the picture.
 
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