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Test Your Astronomy Knowledge
The Demotion of Pluto
The year was 1930. An astronomer, Clyde Tombaugh, was just 24 years old. He was studying the night sky at Lowell Observatory in Arizona when he discovered what would come to be known as Pluto…the ninth planet in our solar system. On January 23, 1930, Clyde saw a dim speck moving among the stars. It was quickly hailed as not only the ninth planet in our solar system, but the first planet discovered by an American. Americans were so proud!
There were a lot of names suggested for the new planet that Tombaugh had discovered. It was his prerogative to choose the name. Suggestions flowed in from all over the world. "Pluto" was suggested by then-11-year-old Venetia Burney from Oxford, England. She wanted to name the planet after Mickey Mouse's dog (Mickey's dog Pluto debuted that same year). Tombough liked the name and chose it. Venetia still lives in England and is quoted as having said, "It has now been satisfactorily proven that the dog was named after the planet, rather than the other way round."
Problem is, Pluto is no longer a planet. It didn't change, disintegrate, or disappear from the night sky. Rather, it fell victim to what some describe as "politics."
Pluto is no longer considered a planet thanks to votes cast by only 424 astronomers (5% of the membership) on the very last day of the meeting of the International Astronomical Union (IAU) in Prague in 2006.
Mike Brown, an astronomer from CalTech (and another American), recently discovered another Pluto-sized object that will not be called a planet either, under the new guidelines.
Many of those who are in a position to know say that the decision will not stand and that textbooks should not be rewritten just yet. The vote has been taken, but the debate isn't over.
See Also:
Space Future
The Demotion of Pluto
The Zodiac
The zodiac is a cycle that covers a year's time. There are several versions of the zodiac system. There is a Babylonian zodiac, an Indian zodiac, a Chinese zodiac, a Western zodiac, and several others. All of the various zodiacs are basically the same. They are all based upon the constellations and they all contain 12 stations, or signs.
The Western zodiac is the one that is mostly used in the United States. Modern Western astrological signs are really just simplifications of the signs used in Hellenistic times.
In the list below are the Roman names for the signs of the zodiac, their ecliptic longitudes of their first points, the symbols that represent them, and the associated dates:
Aries: 0°, the Ram, March 21 to April 20
Taurus: 30°, the Bull, April 20 to May 21
Gemini: 60°, the Twins, May 21 to June 21
Cancer: 90°, the Crab, June 22 to July 22
Leo: 120°, the Lion, July 23 to August 22
Virgo: 150°, the Virgin, August 23 to September 22
Libra: 180°, the Scales, September 23 to October 23
Scorpio: 210°, the Scorpion, October 24 to November 22
Sagittarius: 240°, the Archer, November 22 to December 21
Capricorn: 270°, the Sea-goat, December 22 to January 19
Aquarius: 300°, the Water Carrier, January 20 to February 18
Pisces: 330°, the Fish, February 19 to March 20
Sidereal zodiac astrology (used mostly by Indian astrologists) dates are different from the tropical zodiac astrology dates. However, the tropical zodiac dates are the ones that are used primarily in the West.
Astrology is not an exact science (if you think of it as a science). All of the implications of certain signs and the position of certain planets are open to interpretation. Different astrologists will give different readings based upon the same information.
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More articles:
Curious About Astronomy? Comets, Meteors and Asteroids
Asteroids, Comets, and Meteors Theme Page
Constellation Energy Group
Moon Shot, February 20, 2008
On Pluto’s Demotion
The Constellations
Our Sun
There is nothing remarkable about our sun in the scheme of things. It is very similar to millions of other stars (and our sun is a star) in the universe. You might even call our sun an "average" star.
The energy source for our sun is nuclear fusion. If the total energy output of the sun for just one second could be captured, it would provide the United States with enough energy at the current level of usage for nine million years.
There is a hard core at the center of the sun. The core is so dense and the sun is so large that energy released in the center of the sun takes 50 million years to reach the surface. That means that if the sun suddenly stopped producing any energy at all at the core today, it would be another 50 million years before we noticed it here on earth.
Our sun has been producing radiant and thermal energy for the last four or five billion years. There is enough hydrogen for it to continue producing energy for at least another hundred billion years. In about 10-20 billion years, the sun will begin to expand. It will engulf the closest planets (including Earth), and then it will be a giant red star. In another few billion years after that, our sun will become what is known as a dwarf star.
Most people think of the sun as this large (huge), constant featureless fireball in the sky. The large part is right, but the constant (or steady) and the featureless parts are all wrong. Sunspots are a feature of the sun that was first noted by Theophrastus about 325 BC. A moderate-size sunspot is about the size of Earth. Sunspots come and go over a period of days or weeks.
Related Topics: The Demotion of Pluto,
Basic Astronomy Quiz, The First Seven Astronauts
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