Herophilus
Born: c. 335 BC
Birthplace: Chalcedon, Bithynia
Died: c. 280 BC
Location of death:unspecified
Died: c. 280 BC
Location of death:unspecified
Cause of death: unspecified
Herophilus was an Alexandrian physician who was an early performer of public dissections on human cadavers; and often called the father of anatomy.
As a member of the well-known scholastic community in the newly founded city of Alexandria during the single, brief period in Greek medical history when the ban on human dissection was lifted. Herophilus studied the ventricles (cavities) of the brain, the organ he regarded as the centre of the nervous system; traced the sinuses of the dura mater (the tough membrane covering the brain) to their junction, known as the torcular Herophili; and classified the nerve trunks—distinguishing them from tendons and blood vessels—as motor or sensory.
In the field of medical treatment, Herophilus sensibly recommended good dietand exercise, but was also an enthusiastic advocate of bleeding and frequentdrug therapy.
Herophilus wrote at least nine works, including a commentary on Hippocrates, a book for midwives, and treatises on anatomy and the causes of sudden death, all lost in the destruction of the library of Alexandria around 272 AD.
Source/s: Encyclopedia Britannica
ARISTARCHUS
Born: 310 B.C.
Died: about 230 B.C.
Aristarchus, or more correctly Aristarchos, was a Greek astronomer and mathematician, born in 310 BC on the island of Samos, in Greece. He presented the first known heliocentric model of the solar system, placing theSun, not the Earth, at the center of the known universe. He was influenced by the Pythagorean Philolaus of Croton, but, in contrast to Philolaus, he identified the "central fire" with the Sun, and put the other planets in their correct order of distance around the Sun. For some reason, however, Copernicus, who wrote 1700 years later and knew of Aristarchus' work, is the person most often credited with this heliocentric theory.
Aristarchus’ major extant work, On the Sizes and Distances of the Sun and Moon, consists mainly of meticulous geometric proofs of this and the other hypotheses which he proposes. He describes a spherical Moon, illuminated by the Sun, and much closer to the Earth than the Sun is, a very accurate world-view for the third century B.C. His results were only limited by the accuracy of the measurements of his day, which suffered from a lack of technology.
ARCHIMEDES
Born: 278 B.C.
Died: 212 B.C.
Archimedes was a Greek mathematician, physicist, engineer, inventor, and astronomer. He was born in 278 BC in the port of Syracuse, Sicily (now Italy) in the colony of Magna Graecia. According to the Greek historian John Tzetzes, who was famous for his research on Byzantinne Greek era, Archimedes lived for 75 years. He died in 212 B.C. during the Second Punic war, when Syracuse was captured by the Roman forces after a two year siege.
Archimedes is regarded as one of the leading scientists in classical antiquity. Among his advances in physics are the foundations of hydrostatics, statics and an explanation of the principle of the lever. He is credited with designing innovative machines, including siege engines and the screw pump that bears his name. Modern experiments have tested claims that Archimedes designed machines capable of lifting attacking ships out of the water and setting ships on fire using an array of mirrors.
Archimedes is generally considered to be the greatest mathematician of antiquity and one of the greatest of all time. He used the method of exhaustion to calculate the area under the arc of a parabola with the summation of an infinite series, and gave a remarkably accurate approximation of pi. He also defined the spiral bearing his name, formulae for the volumes of surfaces of revolution and an ingenious system for expressing very large numbers.
Here are some of the works of Archimedes:
On the Equilibrium of Planes (two volumes)
On the Sphere and the Cylinder (two volumes)
On Floating Bodies (two volumes)
Eratosthenes of Cyrene
Born: 276 BC
Birthplace: Cyrene, North Africa (now Shahhat, Libya)
Died: 194 BC
Location of death: Alexandria, Egypt
Cause of death: suicide by voluntary starvation
Eratosthenes of Cyrene was a Greek scientific writer, astronomer, and poet, who made the first measurement of the size of Earth for which any details are known.
One of his major accomplishments in mathematics is his creation of a sieve that determines prime numbers up to any given limit. This sieve, which is called, the Sieve of Eratosthenes, is still important today in number research theory. Eratosthenes figured out that if you were to write down all the natural numbers from 2 to infinity and "sieve out" every second number after two (or multiples of two), then move to the next available number (3) and continue to "sieve out" every multiple of 3 and so on, one would end up with a list of prime numbers.
Eratosthenes is also known for his achievement in astronomy. He found the circumference of the Earth to be nearly 250,000 stadia (25,000 miles). To calculate the circumference of the Earth, Eratosthenes measured the angle of the shadow to the Earth.
As a historian, Eratosthenes decided to work on giving a systematic chronography of the known world by figuring out the dates of literary and political events from the siege of Troy up until his time. However, this was only a beginning. Others built on his foundation.
Sources: Encyclopædia Britannica
HIPPARCHUS
Born: 190 B.C.
Died: 120 B.C.
Hipparchus, or more correctly Hipparchos, was a Greek astrologer, astronomer, geographer, and mathematician of the Hellenistic period. He is considered the founder of trigonometry.
Hipparchus was born in Nicaea, which is now Iznik, Turkey, and probably died on the island of Rhodes. He is known to have been a working astronomer at least from 162 to 127 BC. Hipparchus is considered the greatest ancient astronomical observer and, by some, the greatest overall astronomer of antiquity. He was the first whose quantitative and accurate models for the motion of the Sun and Moon survive. For this he certainly made use of the observations and perhaps the mathematical techniques accumulated over centuries by the Chaldeans from Babylonia. He developed trigonometry and constructed trigonometric tables, and he solved several problems of spherical trigonometry. With his solar and lunar theories and his trigonometry, he may have been the first to develop a reliable method to predict solar eclipses. His other reputed achievements include the discovery of Earth's precession, the compilation of the first comprehensive star catalog of the western world, and possibly the invention of the astrolabe, also of the armillary sphere, which he used during the creation of much of the star catalogue. It would be three centuries before Claudius Ptolemaeus' synthesis of astronomy would supersede the work of Hipparchus; it is heavily dependent on it in many areas.
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