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When was the Sieve of Eratosthenes created?

240 BC

Where do you find the Sieve of Eratosthenes?

Sieve of Eratosthenes

  1. Step 1: Write the numbers 1 to 100 in ten rows.
  2. Step 2: Cross out 1 because 1 is not a prime.
  3. Step 3: Circle 2 and cross out all multiples of 2. (2, 4, 6, 8, 10.)
  4. Step 4: Circle 3 and cross out all multiples of 3.
  5. Step 5: Circle 5 and cross out all multiples of 5.
  6. Step 6: Circle 7 and cross out all multiples of 7.

Where did Eratosthenes grow up?

Eratosthenes was born in the Greek colony Cyrene, now the city of Shahhat, Libya. As a young man, he traveled to Athens to pursue his studies. He returned to Cyrene and made such a name for himself in scholarly endeavors that the Greek ruler of Egypt brought him to Alexandria to tutor his son.

In what country did Eratosthenes live?


Who is the father of Eratosthenes?


What is Euclid famous for?

Euclid, Greek Eukleides, (flourished c. 300 bce, Alexandria, Egypt), the most prominent mathematician of Greco-Roman antiquity, best known for his treatise on geometry, the Elements.

How old is Ptolemy?

Ptolemy was pharaoh of Ptolemaic Egypt from 305/304 BC to his death….

Ptolemy I Soter
Born c. 367 BC Possibly Pella, Macedon
Died January 282 BC (aged 84–85) Alexandria, Egypt

Why was Ptolemy XII expelled from Egypt?

Ptolemy XII was an illegitimate son of Ptolemy IX by an uncertain mother. However, he was forced into a civil war against his mother and brother, Ptolemy X, leading to his exile in 107 BC. Cleopatra III sent her grandsons to Kos in 103 BC.

Who was Ptolemy the first?

Ptolemy I Soter, (born 367/366 bc, Macedonia—died 283/282, Egypt), Macedonian general of Alexander the Great, who became ruler of Egypt (323–285 bc) and founder of the Ptolemaic dynasty, which reigned longer than any other dynasty established on the soil of the Alexandrian empire and only succumbed to the Romans in 30 …

What did Ptolemy invent?

Ptolemy made contributions to astronomy, mathematics, geography, musical theory, and optics. He compiled a star catalog and the earliest surviving table of a trigonometric function and established mathematically that an object and its mirror image must make equal angles to a mirror.

Why did Ptolemy believe the Earth was stationary?

In Ptolemy’s geocentric model of the universe, the Sun, the Moon, and each planet orbit a stationary Earth. Ptolemy believed that the heavenly bodies’ circular motions were caused by their being attached to unseen revolving solid spheres.

What country was Ptolemy from?


Who was Serapis?

Serapis, also spelled Sarapis, Greco-Egyptian deity of the Sun first encountered at Memphis, where his cult was celebrated in association with that of the sacred Egyptian bull Apis (who was called Osorapis when deceased).

How did Ptolemy discover his theory?

Ptolemy developed this idea through observation and in mathematical detail. Based on observations he made with his naked eye, Ptolemy saw the Universe as a set of nested, transparent spheres, with Earth in the center. He posited that the Moon, Mercury, Venus, and the Sun all revolved around Earth.

Who said Sun rotates around Earth?

Nicolaus Copernicus

Why is geocentric model wrong?

The first big problem with the geocentric model was the retrograde motion of planets like Mars. His model has the planets moving around the Sun in circular orbits. This can explain retrograde motion, but his model doesn’t fit all the planetary position data that well.

Why Earth is the center of the universe?

According to Plato, the Earth was a sphere, stationary at the center of the universe. (The number is so high because several spheres are needed for each planet.) These spheres, known as crystalline spheres, all moved at different uniform speeds to create the revolution of bodies around the Earth.

Does the sun revolve?

The sun rotates, but not at a single rate across its surface. The movements of the sunspots indicate that the sun rotates once every 27 days at its equator, but only once in 31 days at its poles. Scientists call this “differential rotation.” Stars near the center revolve around the center faster than those farther out.

Is there a 9th planet?

As of February 2021, no observation of Planet Nine had been announced. While sky surveys such as Wide-field Infrared Survey Explorer (WISE) and Pan-STARRS did not detect Planet Nine, they have not ruled out the existence of a Neptune-diameter object in the outer Solar System.