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The Planet Neptune
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.com -- Astronomers Find Sun's Twin
The Planet Mars
The Planet Saturn
The planet Saturn resembles the planet Jupiter in many ways. Saturn is also a planet that has very little if any solid matter. It is believed that there is a hard rocky core, but that belief is unproven (albeit very probable) theory. Saturn, like Jupiter, is made up of gases and liquids. There is an internal heat source. We know this because Saturn radiates more energy than it receives.
Saturn rotates fast. It makes one complete revolution once every 10 or 11 hours. Saturn rotates around the sun once every 29.5 years. Because it rotates so fast, Saturn is flattened at the poles, making it an almost oblate planet.
The space probes, Pioneer 11, Mariner 11 and 12, and Voyager I and II, provide the best and most accurate information to astronomers about the planet Saturn, even though the Hubble space telescope takes very good images of Saturn. The space probes get "up close and personal," so to speak, and have provided information about Saturn that nothing else could have provided.
Wind velocity on Saturn is extreme. Wind speeds of more than 1,118 mph have been recorded. Unlike the winds on Jupiter, however, wind speeds on Saturn do not seem to be closely related to the positions of the belts and bands.
The rings around Saturn are one of the most interesting features. Really high-resolution pictures taken on the Voyager missions tell us that the rings are actually made up of hundreds of thousands of very small rings. The evidence suggests that the rings are composed of particles that are mostly ice crystals. A lot has been learned about the rings of Saturn over the last 20 or so years, but there is so much about them that is still a mystery. |
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More articles:
Wildlife Watching
Pluto (Disney) - Wikipedia, the free encyclopedia
Science as a Way of Knowing:
The Galileo Project
Doctor Who rubbishes astrology
The Planet Uranus
Mirrors and Lenses
Many people believe that the main function of a telescope is just to make distant celestial objects appear bigger so that astronomers (even amateur astronomers) can see them better, but that really is a misconception. The fact is that telescopes work by gathering light. Magnifying distant objects is secondary. Telescopes gather light basically in two ways: through the use of lenses, and through the use of mirrors. The third way that telescopes gather light is by using a combination of lenses and mirrors.
A telescope that gathers light through the use of a lens is called a refractor telescope. The truth is that how much you spend on a refractor telescope is the determining factor of how well you will be able to see celestial objects. Inexpensive refractor telescopes (2.4 inch) have not-so-good optics and low light grasp. High-end refractor telescopes (3.5 inch) have almost perfect optics and much, much better light grasp.
Telescopes that gather light through the use of a mirror are called reflector telescopes. Refractors cost less per inch of aperture. They are less costly to manufacture because there is only one optical surface, and they lend themselves well to different designs and uses. Also, because the light doesn't have to pass through glass, the images are basically color free. Probably the best telescope for a novice astronomer is the Newtonian reflector. The cost factor is a plus for the refractor telescope, but the corresponding minus (there always is one) is that the primary mirror is ground to a concave shape, so the outside zone has a little longer focal length than the inner zone.
A catadioptic telescope is a compromise between a refractor and a reflector, because both lens and a mirror are used. Catadioptic telescopes are portable. They do not cost as much as a high-quality refractor telescope, but they cost a little more than a good-quality reflector telescope. Still, they are the best of both worlds.
Related Topics: Famous Astronomy Quotes,
The Hubble Space Telescope, Basic Astronomy Quiz
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