One of the oldest earth mysteries was 'what shape is it?' Eratosthenes, in 240 BC, was able to prove the sphericity of the earth and estimate its size to a reasonable margin of error, by comparing the angle of the sun at two distant locations simultaneously. Aristotle knew that the earth was spherical, citing the horizon, the Earth's circular shadow during lunar eclipses, and other phenomena. Many educated people knew about the spherical earth from late antiquity on. However, most Europeans believed that the earth was flat until the explorations of the renaissance.
In the late 19th century a number of alternative theories of the shape of the earth were proposed, flat, hollow and inside-out. By the time the poles had been reached in the early 20th century, the time for these theories had passed. Today, some Biblical inerrantists still believe that the Earth is flat.
This book contains collection of 2 titles:
1. Christian Topography
2. Zetetic Astronomy: Earth Not a Globe
About the Author
Cosmas Indiopleustes, Parallax
Cosmas Indicopleustes was an Alexandrian merchant and later hermit. He was a 6th-century traveller, who made several voyages to India during the reign of emperor Justinian. His work Christian Topography contained some of the earliest and most famous world maps. Cosmas was a pupil of the East Syrian Patriarch Aba I and was himself follower of the Church of the East. Around 550 Cosmas wrote the once-copiously illustrated Christian Topography, a work partly based on his personal experiences as a merchant on the Red Sea and Indian Ocean in the early 6th century. His description of India and Sri Lanka during the 6th century is invaluable to historians. Cosmas seems to have personally visited the Kingdom of Axum in modern Ethiopia, as well as Eritrea, India, and Sri Lanka. "Indicopleustes" means "Indian voyager". While it is known from classical literature, especially the Periplus Maris Erythraei that there had been trade between the Roman Empire and India from the 1st century BC onwards, Cosmas's report is one of the few from individuals who had actually made the journey. He described and sketched some of what he saw in his Topography. Some of these have been copied into the existing manuscripts, the oldest dating to the 9th century. In 522 AD, he visited the Malabar Coast (South India). He is the first traveller to mention Syrian Christians in India.
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines. The term is derived from the Greek meaning "alteration". Nearby objects have a larger parallax than more distant objects when observed from different positions, so parallax can be used to determine distances. Astronomers use the principle of parallax to measure distances to celestial objects including to the Moon, the Sun, and to stars beyond the Solar System. For example, the Hipparcos satellite took measurements for over 100,000 nearby stars. This provides a basis for other distance measurements in astronomy, the cosmic distance ladder. Here, the term "parallax" is the angle or semi-angle of inclination between two sight-lines to the star.
