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ANCIENT ASTRONOMY

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OBJECTIVES

1. discuss the thoughts of philosophers about the shape of the Earth;

2. describe the size of the Earth; and

3. realize the importance of the shape of the Earth.

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ACTIVITY

Directions: Unscramble the letters of each word related to ancient astronomy using the clues that describe it.

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K R G E E S

They are much noted for

their contributions in different fields. They were not only great philosophers but great

scientists and mathematicians as well.

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C I M E L O T P L E D O M

It claims that the planets

moved in a complicated system of circles.

This model also became known as the

Ptolemic System.

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T O B A L E R O D I H S P E

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The shape of the Earth. It

has bulging equator and squeezed poles.

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T O B A L E R O D I H S P E

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The shape of the Earth. It

has bulging equator and squeezed poles.

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T H O N R S R A T

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It was believed to be in fixed

position in the sky. However, when the Greeks traveled to places nearer the equator, like Egypt, they noticed that it is closer to the horizon.

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T H O N R S R A T

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It was believed to be in fixed

position in the sky. However, when the Greeks traveled to places nearer the equator, like Egypt, they noticed that it is closer to the horizon.

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S A R T I T L O E

A student of Plato and

considered as one of the great philosophers

of his time; his earth-centered view

dominated for almost 2,000 years..

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GREEKS

  • great philosophers, scientists, and mathematicians
  • used philosophical arguments to explain the natural

events- movements of the stars and other heavenly bodies

  • measured the sizes and the distances of the sun and the moon using the basics of geometry and trigonometry
  • The early Greeks had a geocentric view of the earth.

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Oblate spheroid

the shape of the Earth.

It has bulging equator and

squeezed poles.

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Solstice

either of the two times in the year,

the summer solstice and

the winter solstice, when the

The sun reaches its highest or

The lowest point in the sky is at noon, marked by the longest and shortest days.

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Eclipse

an obscuring of the light from one celestial body by the passage of

another between it and the observer or between it and its source of

illumination.

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Heliocentrism

the astronomical model in which the Earth and planets revolve around the Sun.

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Geocentrism

any theory of the structure of the solar system (or the universe) in which Earth is assumed to be at the center of it all.

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ANAXAGORAS

Explain what causes the phases of the moon.

According to him, the moon shone only by reflected sunlight. Since it is a sphere, only half of it is illuminated at a time. This illuminated part that is visible from the earth changes periodically.

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ANAXAGORAS

EUDOXUS

Proposed a system of fixed spheres. believed that the Sun, the moon, the five known planets, and the stars were attached to these spheres which carried the heavenly bodies while they revolved around the stationary Earth.

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ANAXAGORAS

ARISTOTLE

A student of Plato. For him, the Earth is spherical in shape since it always casts a curved shadow when it eclipses the moon. Believed that the earth was the center of the universe. The planets and stars were concentric, crystalline spheres centered on the earth.

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ANAXAGORAS

ARISTARCHUS

Aristarchus is the very first Greek to profess the heliocentric view. He learned that the sun was many time farther than the moon and that it was much larger than the earth. Made an attempt to calculate the distance of the sun and the moon by using geometric principles. However, the measurements he got were very small and there were a lot of observational errors.

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ANAXAGORAS

ERASTHOSTHENES

The first successful attempt to determine the size of the earth was

made by him. He did this by applying geometric principles. He observed the angles of the noonday sun in two Egyptian cities that were almost opposite each other- Syene (now Aswan) in the south and Alexandria in the north. He assumed they were in the same longitude.

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ANAXAGORAS

HIPPARCHUS

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ANAXAGORAS

CLAUDIUS

PTOLEMY

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PTOLEMIC MODEL

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According to the Ptolemic Mode, the sun, the moon, and the other planets move in

circular orbits around the Earth. However, if observed night after night, these

planets move slightly eastward among the stars.

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According to the Ptolemic Mode, the sun, the moon, and the other planets move in

circular orbits around the earth. However, if observed night after night, these

planets move slightly eastward among the stars.

Aristotle’s Conclusion

  • Father of Natural - his methods formed the basis of the scientific method.

- Did not believe that the earth is FLAT.

  1. Aristotle considered the position of the North Star.
  2. ships sailing into port.
  3. the shadow cast during eclipses.

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Aristotle’s Conclusion

  • Father of Natural - his methods formed the basis of the scientific method.

- Did not believe that the earth is FLAT.

  1. Aristotle considered the position of the North Star.
  2. ships sailing into port.
  3. the shadow cast during eclipses.

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ACTIVITY

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