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Galaxies
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:
Telescopes for Beginners - Choosing a Beginners Telescope
Astronomy for Kids
The Planet Uranus
William Herschel accidentally discovered the planet Uranus in 1781. Uranus had been seen many times before, but it had always been dismissed as a star.
Uranus is made up mostly of hydrogen and helium like Jupiter and Saturn, but it has higher concentrations of heavy elements. Our closest look at Uranus was given to us by Voyager 2 in 1986.
Uranus is one of the four "Giant Gas Planets" (the other three are Jupiter, Saturn, and Neptune). The rings around Uranus are made up of rock, rather than ice like those of Saturn. We do know that there are five large moons and at least 10 smaller moons. The rotational period of Uranus is a little over 17 hours, and its orbital period is 84 years.
Uranus appears to be a giant blue featureless ball. Voyager 2 got relatively close to Uranus and could not pick up any distinguishable features. It is believed that the upper atmosphere of Uranus has a high-level petrochemical haze that probably obscures features lower in the atmosphere. The blue color is caused by methane gas in the atmosphere. Methane gas absorbs red and orange light, which leaves more blue light.
Voyager 2 confirmed that Uranus has a magnetic field. The field is more than 50 times stronger than that of Earth and is tilted about 60 degrees.
The latest scientific data suggests that Uranus is surrounded by at least five rings. The brightest ring is called the Epsilon ring. Voyager 2 located two small shepherd moons for it, one just inside and one just outside. These two shepherd moons have been named Ophelia and Cordelia.
The most interesting moon that circles Uranus is Miranda. Miranda isn't very big, but it has some very interesting geological features. |
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More articles:
Telescopes for Beginners - Choosing a Beginners Telescope
Famous Meteorites (Cosmic Collisions) - Cosmeo
Ham the Chimp - Wikipedia, the free encyclopedia
Pluto demoted - no longer a Planet!
Physics/ Astronomy Assistant Professor | Los Rios Community ...
Carl Sagan
History of Astronomy
Astronomy is the oldest of all sciences. It has its roots back in the beginning of time. There is evidence of astronomy playing a large role in religious, mythological, and astrological practices of pre-history. Mankind has always looked to the heavens with wonder mixed with a healthy dose of curiosity.
In the earliest cultures, heavenly bodies were identified as gods or spirits, and these gods and spirits were thought to control such things as rain, drought, seasons, and the tides. The first astronomers are believed to have been priests or Magi. The earliest calendars were based upon the phases of the moon and the time between phases.
Western astronomy has its roots in ancient Mesopotamia astrology. The modern practice of dividing a circle into 360 degrees, of 60 minutes each, began in ancient Mesopotamia with the Sumerians.
The oldest astronomical writing that we have is Tablet 63 of the Enuma Anu Enlil. It is called the Venus tablet of Ammi-saduqa. The Venus tablet lists the first and last visible risings of Venus over a period of about 21 years, and it is the earliest conclusive evidence that the phenomena of a planet were recognized.
Since the beginning of time, man has looked up. The sky, particularly the night sky, has been full of mystery that humankind wanted to understand.
The old civilizations of China, India, Greece, and Rome all looked to the stars for explanations to earthly situations and problems, inspiration and guidance. They found all of those things, but they also found knowledge, and over the centuries our knowledge of astronomy has grown. But there are those who believe that we have only just begun to learn all the heavens have to teach us.
Related Topics: About Telescopes,
Ancient Astronomical Calendars, Guide to Buying a Telescope
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