The document discusses astronomy concepts before the invention of the telescope. It describes how ancient Greeks like Pythagoras, Plato, and Aristotle developed early models of the universe and proved the Earth was round based on observations of the sky. It also discusses astronomical phenomena that were observable without telescopes, including the motions of planets, stars, and constellations; comets; eclipses; and phases of the moon.
2. HOW DOES THE ANCIENT
GREEK PROVED EARTH
WASN’T FLAT
ASTRONOMY BEFORE
THE INVENTION OF THE
TELESCOPE
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3. What is Science
Science as “a collection of known truths
about the Universe that develops and
expands over time.”
Science is a dynamic and ever changing
Science develops when better models are
found, clearer and more useful
mechanisms are used to explain a group
of phenomena, more accurate and precise
details are observed and many more
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4. HOW DOES THE ANCIENT
GREEK PROVED EARTH
WASN’T FLAT
5. 5
•Astronomy is a major influence on the
development of Physics
•In the ancient Greek Philosophy,
cosmology and astronomy are interrelated
with each other.
•The Greeks divided the universe into
domains, the celestial domain and the
terrestrial domain
6. Diurnal Motion of the Sky
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•The appearance that the objects in the
sky moves relative to the Earth’s local
horizon (celestial objects: moon, Sun,
stars, planets: Mercury, Venus, Mars,
Jupiter, Saturn ) as observed for one
whole day at the same location on earth.
(Rotation)
7. Annual Motion of the Sky
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•The appearance that objects in
the sky moves relative to the
background stars as observe at
the same time of the day and at
the same location on earth.
(revolution)
10. 10
•Pythagoras (c. 570 - c. 495 BC)
— Universe is mathematical;
mathematics as the best way to
express truth about the Universe;
Sun, moon and Earth are
spherical; placed Earth as the
center of the Universe.
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•Plato (c. 427 - c. 347 BC)
— attainment of perfection as absence of
change; mathematical symmetries to
demonstrate perfect shapes (sphere and
circle); celestial spheres being crystalline and
contains the moon, the Sun and the stars;
explaining the shadows as his description or
framework on how to look at the Universe,
that the daily and annual patterns of the sky
must have a greater reality besides its
appearance.
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•Eudoxus of Cnidus (408 - 355 BC)
— followed previous models of the
universe but added auxiliary spheres
to provide appropriate tilt to the
planets’ path.
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•Aristotle (384 - 322 BC)
— two-domain system with terrestrial
domain containing four elements that
tries to attain perfection by being in
their natural location relative to the
center of the Universe: the center of
the Earth. He was a learner of Plato
14. TWO DOMAINS VIEW OF THE
UNIVERSE
CELESTIAL
• Perfect hence can only be
made up of the perfect
substance they called “ether”
can only move in perfect
motion: circular in path and
constant in speed
TERRESTRIAL
• Objects are imperfect and the
tendency of things to attain of
perfection of things to attain
perfection is the cause of their
motion
• Believe that things, depending on
their composition of the elements –
fire, air, water, and earth – tend to
move towards the center of the
Universe (center of the Earth) or
away from it with earth, naturally as
at the center. Fire and Water
naturally move away from the center
17. MOTION IN THE SKY
Dating back to 1800 B.C, the Babylonians were among the
first civilization to document the movements of the sun and
the moon. They maintained a very detailed record of these
motions including a daily, monthly and yearly position of
the celestial bodies.
This information was initially of mystical value used to warn
the king about the possible catastrophic events. It is said
that the first appearances of the famous Hailey’s come
were document by the Babylonians and it is also them who
first divide the sky into zones
18. PATTERN OF STARS AND
CONSTELLATION
• What is constellation?
- A constellation is a group of visible stars that form a
pattern when viewed from Earth. The pattern they form
may take the shape of an animal, a mythological creature,
a man, a woman, or an inanimate object such as a
microscope, a compass, or a crown.
How many constellation are there?
- The sky was divided up into 88 different constellation in
1922. This included 48 ancient constellation listed by the
Greek Astronomer Ptolemy as well as 40 new
constellations. 18
19. USES OF CONSTELLATION
•Constellation are useful because they can help
people to recognize stars in the sky. By looking
for patterns, the stars and location can be
much easier to spot.
•The constellation has uses in ancient times.
They were used to help keep track of the
calendar. This was very important so that
people knew when to plant and harvest crops
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20. •Another important use for constellations
was navigation. By finding Ursa Minor it
is fairly easy to spot the North Star
(Polaris). Using the heigh of the North
Star in the sky, navigators could figure
out their latitude helping ships to travel
across the oceans
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21. GEOCENTRIC VIEWS
• Humans have come up with several models in an effort to
understand the universe. Before the invention of the telescope,
they had to rely on their senses for a picture of the universe with
much philosophical and religious symbolism.
• Around 600 BCE, Thales of Miletus proposed that Earth is a
disk floating on water.
• In 520 BCE, Anaximander also from Miletus, suggested that
Earth is a cylinder and its surface is curved.
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22. PHYTHAGOREAN MODEL
• Acknowledge to be the first to assert that Earth is
round, and that the heavenly bodies move in
circles.
• The Earth is at rest at the center of the Universe
and everything rotates around it.
• He considered that the motions of the planets
were mathematically related to musical sound
and numbers. These ideas are called “The Music
of the spheres
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23. PRESENT OF COMETS
•Comets have inspired dread, fear, and awe in
many different cultures and societies around the
world and throughout time. They have been
branded with such titles as “the Harbinger of
Doom” and “the Menace of the Universe “. They
have been regarded both as omens of disasters
and messengers of the gods
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24. • When people living in ancient cultures looked up
comets, were the most remarkable objects in the
night sky. Comets were unlikely any other objects
in the night sky. Whereas most celestial bodies
travel across the skies at regular, predictable
intervals, so regular that constellations could be
mapped and predicted, comets’ movements have
always seemed vey erratic and unpredictable.
This led people in many cultures to believe that
the gods dictated their motions and were sending
them as a message.
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26. •Mercury, Venus, Mars, Jupiter and Saturn are
easily seen in the sky without the aid of
telescope. These planets can be easily
confused with stars and are only seen at
specific times of the day. The best time to look
for these planets would be before sunrise and
after sunrise.
•Even before the invention of the telescope,
ancient people have already observed different
astronomical phenomena. The most observable
objects in the sky are sun and moon.
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27. • Babylonian and Egyptian civilizations used primitive
version of a sundial, called gnomon, in systematically
observing the motion of the sun. By looking at the
shadows that the gnomon casts, they were able to
observe that the sun rises in the eastern part of the
sky, reaches its highest point in midday, and sets in
the western part of the sky.
• Also, they recorded that the points where the sun
rises and sets on the horizon varies over a year and
these variations happen periodically. They observed
that these variations are related to weather and so
concluded that seasonal changes in climate happen
during a course of one year.
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28. PHASES OF THE MOON
•Ancient people have observed that the
moon change its path and its appearance
within a period of 29.5 days. They observed
that the moon changes its appearance from
thin semi-circular disk to full circular disk.
These phases of the moon is the basis of
ancient calendars.
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29. ECLIPSE
• Besides their observation in the different phases of
the moon, they also noticed that there are times when
the mood or part of it seemed to be covered by a
shadow for a brief moment. A lunar eclipse occurs
when the Earth cast its shadow on the moon when the
Earth is between the Sun and the Moon.
• A phenomenon such as this is known as a lunar
eclipse where in the moon changes into a dark or
blood red color.
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