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Space Travel
Space Travel
Since the beginning of time, people have looked to the heavens with wonder. In the book of Genesis in the Bible, the people decided to build a tower that would reach heaven. According to the scriptures, God saw that people could do anything they wanted to do if they worked together, so He caused people to speak different languages and scattered them around the earth -- He later destroyed the tower as well. The attempt to build the Tower of Babel happened after the great flood, but before Abraham's covenant with God. Yes, humans have always been fascinated by the sky…the heavens….and the desire to reach out and touch it.
Back in the 1960s, President John Kennedy challenged America to put a man on the moon before any other nation could accomplish the feat. On July 16, 1969, Apollo 11 was launched from the Kennedy Space Center with astronauts Neil Armstrong, Michael Collins, and Edwin E. Aldrin, Jr. aboard; the destination was the moon. On July 20, 1969, Neil Armstrong became the first man to set foot on the moon. He uttered the historic words, "One small step for a man, one giant leap for mankind." Space travel became a reality.
Since that historic day in 1969, we have sent unmanned space craft to Mars and Saturn. They have sent back some truly amazing photographs. We are learning more and more about our solar system and the other plants that circle our sun.
America's space program is still at work and the possibility of space travel is a very real possibility. There are many problems that must be overcome before a manned space craft can be launched and sent to other planets, but I do believe that someday it will happen -- maybe not in my lifetime, but someday.
See Also:
Christopher Wren - Wikipedia, the free encyclopedia
Guide to Buying a Telescope
The Planet Mercury
The planet Mercury is the smallest planet in our solar system, and the one that is closest to the sun. This proximity to the sun has made it difficult to study the planet. The closest look that we have ever had was in 1974 and 1975 when the unmanned Mariner 10 was sent to map the surface of Mercury. Only about 40% to 45% of the surface was actually mapped.
Mercury resembles our moon in appearance as it is heavily cratered. There is an atmosphere of sorts on Mercury but not one that would sustain life as we know it. The atmosphere is very unstable and is made up of hydrogen, helium, oxygen, sodium, calcium and potassium.
Records of studies made of Mercury date back to 300 BC. The name "Mercury" was given to the planet by the Romans after the god Mercurius. Chinese, Korean, Japanese, and Vietnamese cultures refer to Mercury as the water star based on the Five Elements. Other cultures have called the planet by other names. The Babylonians, for example, called the planet Nabu or Nebu after the messenger to the Gods in their mythology.
The temperature on Mercury varies. The average temperature is 179° C, but the extremes are a low of -183 °C to a high of 427° C. Sunlight on Mercury is six and a half times stronger than it is on Earth.
There is evidence that water does exist on Mercury despite the extreme temperature variations. The bottoms of some of the deepest craters near the poles are never exposed to direct sunlight. Temperatures in these areas remain far lower than the global average, so it is possible for ice to exist. |
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Mirrors and Lenses
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.
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The Planet Jupiter, Amateur Astronomy
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