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HOW TO MEASURE THE EARTH WITH A STICK

        Have you ever heard of the Greek mathematician and astronomer Eratosthenes? His name is probably best known among astronomers. Why do they think so highly of him?           Eratosthenes was born about 276 B.C.E. and received some of his education in Athens, Greece. He spent a good part of his life, however, in Alexandria, Egypt, which at that time was under Greek rule. In about 200 B.C.E., Eratosthenes set out to determine the dimensions of the earth by using a simple stick. ‘Impossible!’ you may say. How did he do it?         In the city of Syene [now called Aswan], Eratosthenes observed that at noon on the first day of summer, the sun was directly overhead. He knew this because there was no shadow cast when the sunlight reached the bottom of deep wells. However, at noon on the same day in the city of Alexandria, which was located 5,000 stadia to the north of Syene, a shadow could be observed. That gave Eratosthenes an idea.       Eratosthenes set up a gnomon, a simp

MYSTERIOUS DISCOVERIES ABOUT OUR PLANET

                                         Astronomers have discovered that they do not know what makes up over 90 percent of the universe. What is more, the discoveries that led to question their understanding of the fundamentals of physics itself. Of course, such questions are nothing new.           Toward the end of the 19 th century, physicists observed something odd about the speed of light. They found that relative to an observer, light always traveled at the same speed no matter how fast the observer was moving. But that seemed to defy natural law! The problem was addressed in 1905 in Albert Einstein’s special theory of relativity, which showed that distance [length], time, and mass are not absolutes. Then, after a flash of intuition that he termed “the happiest thought of my life,” Einstein began to develop his general theory of relativity, which he published in 1916. In this revolutionary work, Einstein wove gravity , space, and time together and refined the phys

THE EARTH PILLAR, DEMOISELLE, OR HOODOO

                                       A tall column of earth, often 20 to30 feet high, capped by a large boulder. The boulder has originally lain on the soil; when most of the soft surface material surrounding it has been gradually worn away by rain, it has protected the earth beneath it, and has remained perched on a long pillar of this earth. Earth pillars occur frequently in mountain valleys, and probably the best-known examples are those of the Tyrol.                                          

HOW TO MEASURE THE EARTH WITH A STICK

        Have you ever heard of the Greek mathematician and astronomer Eratosthenes? His name is probably best known among astronomers. Why do they think so highly of him?           Eratosthenes was born about 276 B.C.E. and received some of his education in Athens, Greece. He spent a good part of his life, however, in Alexandria, Egypt, which at that time was under Greek rule. In about 200 B.C.E., Eratosthenes set out to determine the dimensions of the earth by using a simple stick. ‘Impossible!’ you may say. How did he do it?         In the city of Syene [now called Aswan], Eratosthenes observed that at noon on the first day of summer, the sun was directly overhead. He knew this because there was no shadow cast when the sunlight reached the bottom of deep wells. However, at noon on the same day in the city of Alexandria, which was located 5,000 stadia to the north of Syene, a shadow could be observed. That gave Eratosthenes an idea.       Eratosthenes set up a gnomon, a simp

HOW TO MEASURING THE EARTH WITH A STICK

                                      Have you ever heard of the Greek mathematician and astronomer Eratosthenes? His name is probably best known among astronomers. Why do they think so highly of him?           Eratosthenes was born about 276 B.C.E. and received some of his education in Athens, Greece. He spent a good part of his life, however, in Alexandria, Egypt, which at that time was under Greek rule. In about 200 B.C.E., Eratosthenes set out to determine the dimensions of the earth by using a simple stick. ‘Impossible!’ you may say. How did he do it?         In the city of Syene [now called Aswan], Eratosthenes observed that at noon on the first day of summer, the sun was directly overhead. He knew this because there was no shadow cast when the sunlight reached the bottom of deep wells. However, at noon on the same day in the city of Alexandria, which was located 5,000 stadia to the north of Syene, a shadow could be observed. That gave Eratosthenes an idea.       Era