1) Ancient civilizations believed the Earth was flat until the Greeks proposed it was spherical based on observations of lunar eclipses and the circular shadows cast on the Moon. 2) Early models of the universe placed Earth at the center, with Copernicus and others later advocating heliocentric models with the Sun at the center. 3) Galileo's observations with early telescopes, such as the moons of Jupiter and sunspots, provided evidence supporting heliocentric models and advancing astronomical understanding.

1. ASTRONOMICAL
PHENOMENA
KNOWN TO
ASTRONOMERS
BEFORE TELESCOPE

2. GREEKS PERSPECTIVE
OF THE
EARTH’S SHAPE

3. During the ancient times, Earth was perceived to
be flat. Babylonian, Chinese, Egyptian, and
Hebrew civilization believed that earth had
corners. It was then believe that if you set to sail
straight in the ocean, you would get to the edge
of Earth and fall.

4. • Greeks believe that the earth was round, not flat.
1. Pythagoras- first propose a spherical earth.
2. Plato- educated his students on the sphericity of earth but made no justific
ations.
3. Anaxagoras- he further supported Pythagoras proposal through his obser
vations of the shadows that the earth cast on the moon during lunar eclips
e. A circular shadow of earth was reflected on the moons surface.
4. Aristotle- he argued that is the shape of the sun and the moon is sphere th
en perhaps the earth was also sphere.
PHILOSOPHERS THAT THEORIZED
THAT EARTH WAS ROUND

5. Navigators such as Ferdinand Magellan
and Juan Sebastian Elcano were given
credit for circumnavigating the world and
proving that earth is not flat.

6. GREEKS PERSPECTIVE
OF THE
EARTH’S SIZE

7. He gave the most accurate size
of the earth during their time.
From his measurement, he
computed that the circumference
of the earth is 40,000 km.
ERATOSTHENES

8. DIFFERENT MODELS
OF THE UNIVERSE

9. Before the invention of telescope,
ancient astronomers only used their
unaided eyes to observe the sky and
the stars. Eventually, they created
models of the universe.

11. EUDOXUS OF CNIDUS
The first astronomer to give the model of
universe. He state that the universe was
composed of Earth, five other planets
( Mercury, Venus, Mars, Jupiter And Saturn),
Sun, Moon and Stars.

13. ARISTOTLE
Just like Euxodus, Aristotle showed that the
universe was spherical and the earth was at
the center of the universe and was stationar
y. He believe that the earth is too heavy and
big to move, thus, it could not rotate. And th
e earth is composed of four elements- earth,
water, air and fire.

15. ARISTARCHUS
A Greek philosopher who made a first atte
mpt to create a heliocentric model. He propo
se that the sun and the star were at rest, wh
ile earth revolved around the sun in circular
path.

17. CLAUDIUS PTOLEMY
His model is called as Ptolemaic universe. In this
model, it is assumed that earth was at the center
of the universe while other celestial bodies
revolved around the earth in perfect circles with
constant velocity. His model is consider to be
more refined than previous geocentric model as
it can explain the motion of celestial bodies
accurately.

19. NICOLAS COPERNICUS
Revived the heliocentric model of Aristarchus.
He concluded that the following:
1. Heavenly bodies exhibited constant circular and
perpetual motion along their epicycles
2. The sun was at the center of the universe.
3. The order of the planets from the sun is Mercury,
Venus, Earth and Moon, Mars, Jupiter, Saturn an
d beyond the planets were the fixed star.

21. TYCO BRAHE
A Danish astronomer who made a
geoheliocentric planetary model. Earth
was at the center and sun and moon
revolved around it, and all the other
planets orbited the sun.

23. OBSERVED AND
RECORDED
ASTRONOMICAL
PHENOMENA

24. Pleiades Star Cluster- the
Pleiades is a star cluster that
is visible to the unaided eye.
Once this star cluster appears
in the sky, the Incas mark this
as the start of their year.

26. Constellations- Egyptians saw
pattern of stars as constellation
and is used as representation of
their gods and also used to
determine when to plant and
harvest crops. It also help then in
navigation.

28. First sight of Venus- this planet is
considered the third brightest in
the sky. In the Mayan culture, the
position of Venus was used as
basis in deciding whether to start
a battle against other tribe.

30. UNIVERSE IN
GALILEO’D EYES

31. The Universe in Galileo's Eyes
Galileo Galilei's use of telescope for astronomical
purposes that allowed him to discover many
significant astronomical phenomena which later
on were studied by astronomers from the
different parts of the world.

32. Lunar Craters - Using his telescope (8x magnification
), Galileo confirmed that there were mountains on the
moon. Toward the end of November 1609, he
constructed a 20x magnification telescope which
helped him gather better lunar observations. He also
observed the craters on the moon.

34. Moons of Jupiter - In 1610, Galileo
saw Jupiter accompanied by four
seemingly fixed "stars." These fixed
stars were later on identified as the
moons of Jupiter.

36. Sunspots - These are dark spots on the sun which
are relatively colder than the other areas in the sun.
Galileo was one of the first astronomers to observe
this phenomenon. Other astronomers thought the
sunspots are not on the surface of the sun. It was
Galileo who proved mathematically that these spots
are indeed on the sun's surface.

38. GREEKS STUDY
OF
MOTION AND EARTH

39. Aristotle's View of Motion
For Aristotle, motion did not only refer
to locomotion or a change in position.
He classified motion as terrestrial (or
sublunar) and celestial.

40. Three Types of Terrestrial Motion
Natural Motion- the movement of objects on Earth goi
ng back to its original place.
Unnatural Motion- type of terrestrial motion is violent
because the object was removed from its natural place.
Celestial Motion - the motion of celestial bodies in unif
orm circular motion.

41. Hipparchus was able to explain the precession of
equinoxes. Precession of equinoxes refers to the
movement of Earth relative to its orbital plane.
This phenomenon accounts for the seemingly
continuous displacement of stars relative to the
equinoxes.
Hipparchus's View of Motion

42. Since during his time a Geocentrism was widely
known observers from Earth thought that a star
has moved when in fact it is not the star’s
location that has moved but Earth that is slowly
moves away from its original orbital plane. This
means that Earth is not actually stationary all the
time.
Hipparchus's View of Motion

43. Copernicus's View of Motion
Copernicus studied the motion of Earth. He had two
descriptions of Earth's motion based on his
observations (rotation and revolution) which are
classified as either
1. Diurnal (Daily) Motion
2. Annual (Yearly) Motion

44. Diurnal motion refers to the rotation of Earth
about its axis from west to east. As Earth rotates,
some of its parts are exposed to the sun's rays while
other parts are not. This results in the occurrence of
day and night. Thus, a day is technically the time
required to complete one cycle of a diurnal motion/
rotation.

46. Annual motion refers to the movement
of Earth in reference to the sun. There are
two types of annual motion:
 Earth's revolution
 Tiltation.

48. Earth revolves around the sun from west to east. This takes a
round 365 1/4 days (365 days and 6 hours) to be completed a
nd is the reference for the number of days in a standard year.

49. The occurrence of seasons (spring, summer, autumn, and
winter) is a consequence of both Earth's revolution and tilted
axis.

50. Brahe’s
Contribution in
Observational
Astronomy

51. One of Brahe's greatest contributions to astronomy
was the Rudolphine Tables. These tables were
records of celestial observations he made using his
crude astronomical instruments.
His tables were more refined
and organized than the
astronomical tables made
before him .

52. Kepler's Laws of Planetary Motion
According to some accounts, on Tycho's deathbed, he as
ked his assistant Johannes to continue what he started
by completing his astronomical tables. Kepler, who was a
German mathematician and astronomer, became
famous for his laws of planetary motion:
1. Law of Ellipses
2. Law of Equal Areas
3. Law of Harmonies.

53. Each planet moves in an elliptical path, with
the sun at one focus
• Aphelion is the point in a planet’s orbit
that is farthest from the sun.
• Perihelion is the point in Earth's orbit
that is nearest to the sun.
Law of Ellipses

55. As a planet moves at any point
along its elliptical orbit, it travels
equal areas of space in equal
periods of time.
Law of Equal Areas

57. The squares of the revolutions of
the planets are directly proportional
to the cubes of their average
distances from the sun.
Law Of Harmonies

59. Thanks !