Computer Science Illuminated, Third Edition

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Stonehenge

The mystery and intrigue that surround Stonehenge have led generations of scholars, scientists, artists, and writers to imagine and contemplate the why's and how's of its origin. A stunning megalithic monument, Stonehenge rises up from the Salisbury Plain landscape serving as a relic from a time long gone. Not only is Stonehenge potentially a window into religious history but Stonehenge also provides insight into early fascination with astronomy and mathematics.

Knowledge of Stonehenge, which literally means "hanging stone," has been derived from numerous excavations and archeological investigations. From this research, it is believed that the site was constructed in three stages, a task that spanned over 25 generations. Different theories exist as to who was involved in the construction. Gerald Hawkins, author of Beyond Stonehenge asserts that it was not the Druids, as often believed, but rather that each phase of the monument was erected by a distinct group of people: the secondary Neolithic people, the Beaker people, and finally the Wessex people. Regardless of who contributed, the construction of Stonehenge, which required an incredible commitment of resources, suggests that its purpose was of inherent importance. Before speculating on the why's of Stonehenge, let's look at its construction in more detail.

In its first construction phase, c.a. 3000 BC, a few standing stones and a number of wooden poles were erected; the site was presumably used in burial rituals. Fifty six pits, later named "Aubrey holes," were dug at this time and may have helped hold the wooden poles. A wide circular ditch was created forming the perimeter of current day Stonehenge, and an avenue to water was carved out of the landscape. Of the stones raised during this time, one was the "Heel stone" which weighed over 30 tons.

The second stage of development took place at approximately 2800 BC and while the events of this time are uncertain, it is likely the construction involved the raising of nearly 80 giant bluestones in two rings. These bluestones were transported to Stonehenge from the Preseli Mountains in Southern Wales in what must have been an undertaking of mammoth proportions, considering the size and weight of the stones, as well as the available technology. While most theorists believe that the stones were transported by water using rafts and manpower, new ideas suggest that in earlier times glaciers may have moved the bluestones closer to Stonehenge, making them more accessible for use in the monument. The bluestones, weighing up to 45 tons, were arranged at Stonehenge in this period, only to be dismantled and rearranged in the third evolutionary phase of Stonehenge.

This third period of construction took place between 2000 and 1500 BC and can effectively be divided into three distinct segments. First Stonehenge achieved the shape and design that we recognize today. Thirty massive sarsen rocks were placed to encircle five trilithon arches, each of which was made of two closely standing sarsen stones with a third stone laying across the pillars. The trilithon arches are the characteristic feature of Stonehenge. Centrally located, the trilithon arches formed a horeshoe that opened eastward toward the rising sun. The sarsen stones that encircled these arches were aligned together with impressive precision. In addition, a smaller horseshoe of bluestone was erected in the center of the trilithon arches. The bluestones of previous eras were dismantled and rearranged in this final major development that forms our current image of Stonehenge.

The masterful engineering of Stonehenge is rivaled in intrigue only by the mystery surrounding its purpose. Why was Stonehenge created? Was its purpose religious? Some speculate that Stonehenge served as a temple for worship, a memorial for victims of warfare, or a holy place for religious festivals and rituals. One particular possibility stands apart from the rest: was Stonehenge created for mathematical and astronomical purposes? Evidence suggests that the builders of Stonehenge strategically aligned the sarsen stones so that they functioned as a megalithic calendar. Each year on the solstice, the sun rises with perfect alignment to the Heel stone. The trilithons, moreover, are highlighted during key dates throughout the year. The layout at Stonehenge allows for prediction of lunar eclipses, and holds within its arrangement knowledge of the lunar cycle and the moon's orbit around the earth. Gerald Hawkins has delved with great detail into the scientific purpose of Stonehenge in his book Stonehenge and Beyond. His research attests to the incredible accuracy with which the stones are aligned, their purpose clearly extending beyond religious to mathematical.
The above photo is Courtesy of Scott Barrett

Additional Links
Stonehenge
For more information on Stonehenge, as well as images that map out the construction of the site, visit this website: Earth Mysteries: Stonehenge.

Visit the Stonehenge web site

From a Garage to the Fortune 500

The story of Apple Computer begins long before the incorporation of the partnership between Steve Wozniak and Steve Jobs. In high school, both boys were very interested in electronics, and were considered outsiders by most of their classmates. When they graduated from high school, Wozniak went to University of California, Berkeley, and Jobs ventured to Reed College in Oregon. Steve Wozniak aspired to be an engineer; he was fascinated by mathematics and actively applied his knowledge whenever he could. He loved inventing gadgets and tinkering with electronic devices. Wozniak decided to leave school in the mid 1970s, and began working for Hewlett Packard. Jobs likewise left school before finishing his degree. Atari hired Jobs, who in a few months had saved enough money to travel to India on a spiritual journey of sorts. His adventure eventually took him back to California where he soon reconnected with Wozniak and began attending Wozniak's "Homebrew Computer Club" meetings. Woz meanwhile was actively involved in the latest technology. He and John Draper created "blue boxes," devices that enabled phone hackers to make long distance calls for free.

Jobs recognized that Wozniak's skills in electronics were superior to his own, but Wozniak was developing technology for the simple joy of it, and Jobs saw a money-making opportunity. Jobs convinced the engineering whiz Wozniak to work with him to create a personal computer. In 1976, Wozniak developed the Apple I and Jobs took the lead in marketing the item. It was not until Apple II debuted in 1977, however, that the invention made a splash. Sales were increasing and soon gained momentum with the creation of the Apple Disk II in 1978. By 1980, Apple Computer had become and international company with thousands of employees. Today it stands as a principle player in computer technology, and "apple" is a household name.

Wozniak and Jobs capitalized on what they knew best: Wozniak used his talent as an engineer and his interest in gadgets to create and invent new technology, and Jobs utilized his entrepreneurial spirit and courage to take a great idea and make it available to millions of people.

Additional Links
Apple Computer
Read more about the history of Apple Computer as well as its current endeavors on the Apple History website.

Visit the Apple Computer web site
 
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