MODULE 1

• is a collection of known truths about the Universe that develops andexpandsovertime

  Science
• is another word for universe and cosmology is the study of the origin, evolutionandfate of the universe.


  . “Cosmos”
• Greeks believed that objects were made up of four elements

  : air, earth, fire, andwater.
• the Universeisdividedinto two domains:

  Terrestrial and Celestial domains.
• is perfect hencecanonly be made up of the perfect substance they called “ether” and can only move inperfect motion:circular in path and constant in speed.

  Celestial domain
• objects are imperfect and that the tendency of things to attain perfection is the cause of their motion

  Terrestrial domain
• is believed that bring things towards their more perfect state. Thus, heavy objects fall “faster” than lighter ones.

  natural motion
• Categories of Motion According to Aristotelian Mechanics:

  The tendency of objects to go back to their natural state. For example, the natural motionof a rock, which is made up of the element earth, is to go downward or toward the ground. Thisnotion explained why a stone that thrown upward always fell back to the ground.

  Natural Motion
• Aristotelian Mechanics:

  The ability of humans (as well as other animals) to move because they have the will or thecapacity to do so

  Voluntary Motion
• Categories of Motion According to Aristotelian Mechanics:

  The motion caused by unnatural conditions. For example, a plant does not have theabilitytomove around, but it can be mechanically moved by air or water.

  Involuntary Motion
• Non-Terrestrial Motion According to the Ancient Greek Astronomers:

  daily motion of the sky — refers to the apparent movement of stars and other celestial bodies around the Earth. It is caused by Earth’s rotation from west to east. The appearance the objects in the sky moves relative to the Earth’s local horizon

  Diurnal motion
• refers to the apparent yearly movement of the Sun across a background of stars. This movement is caused by Earth’s revolution around the Sun

  Annual motion
• Non-Terrestrial Motion According to the Ancient Greek Astronomers:

  which was historically called the precession of the equinoxes because the equinoxes moved westward along the ecliptic relative to the fixed stars, opposite to the early motion of the Sun along the ecliptic. Precession refers to the conical motion of Earth’s axis as it spins. Because of precession, completing one cycle every 26, 000 years.

  Earth’s precession
• proposed that Earth was round.

  Pythagoras
• conducted observations that supported Pythagoras’ proposal. He observed that during a lunar eclipse, the Earth’s shadow was reflected on the moon’s surface. The shadow was circular

  Anaxagoras
• listed several arguments for a spherical Earth, which included the shape of the moon and the Sun, the positions of the North Star, and the disappearance of the ships when they sailed over the horizon.

  argued that if the moon and the sun were both spherical, then perhaps, Earth was also spherical

  Aristotle
• attempted to measure the circumference of the Earth. He receivedcorrespondence from Syene in Southern Egypt. It stated that a vertical object did not cast anyshadow at noontime during the summer solstice.

  Eratosthenes
• • There were several models of the universe presented and the most common were the ----- and the ---- models of the solar system.

  Geocentric, Heliocentric
• posits that the Earth is at the center of the universe.

  GEOCENTRIC MODEL
• •GEOCENTRIC MODEL VARIATIONS:

  Eudoxus of Cnidus (born c. 395 – 390 B.C.), a Greek astronomer and mathematician, was the first to propose a model of the universe based on geometry. His model composed of 27 concentric spheres with Earth as the center.

  Eudoxus’ Model
• GEOCENTRIC MODEL:

  he considered these spheres as physical entities. He thought that these spheres were filled with the divine and eternal “ether” that caused the spheres to move. He introduced the Prime Mover as the cause of the movement of the spheres. His model composedof56spheres that guided the motion of the Sun, the Moon, and five known planets. As the spheres moved,they maintained the same distance from the Earth. Also, they moved at constant speeds

  Aristotle’s Model
• GEOCENTRIC MODEL

  He thought Earth was at the center, and around it were the Sun, Moon, planets, and stars, all moving in perfect circles. However, observations showed otherwise. The paths of the celestial bodies are not circular, and they vary in distances

  suggested that planets like Mars move in circles as they orbit the Earth, where the circles are called epicycles. The center of the epicycle then moved on a larger sphere called a deferent.


  Ptolemy’s Model (the great geometer)
•  posits that the sun is at the center of the universe. This model gained popularity in the 16th century and was eventually accepted as the correct model.

  HELIOCENTRIC MODEL
• HELIOCENTRIC MODEL:

   Nicolaus Copernicus, a Renaissance mathematician and astronomer born in Poland, ended the geocentric astronomy era by publishing his work On the Revolutions of the Heavenly Spheres wherein he explained that the Sun, not the Earth, is the center of the universe. In his work, he reiterated the ancient Greek concept that the motion of spherical heavenly bodies is uniform, eternal, and circular

  Copernicus’ Model
• HELIOCENTRIC MODEL:

  Aristarchus of Samos (born c. 310 B.C.), a Greek astronomer and mathematician, was the first to hypothesize that the Sun is the center of the universe. He visualized that the Moon orbits around a spherical Earth which then revolves around the Sun. He believed that the stars are very far away from the Earth as evidenced by the absence of stellar parallax – that is, the stars do not change positions relative to each other as the Earth revolves around the Sun.

   Aristarchus’ Model
• HELIOCENTRIC MODEL:

  Tycho Brahe was the last and graetest astronomer prior to the imvetntion of the telescope. He thought Earth was at the center, but everything else orbited around the Sun. He believed that the Sun went around Earth, but all the other planets went around the Sun.

  Tycho Brahe Universe