Transcript BABYLON and SUMERIA 3000BC

ASTRONOMY
The study of the
universe
Who were some of
the earliest
astronomers?
Chinese
Observation and record
keeping goes back more than
4000 years.
Of particular interest to early Chinese
astronomers were solar eclipses.
An astronomical tool that was
especially important to early Chinese
astronomers was the gnomon. A
gnomon is simply an object—a post
stuck in the ground, for instance—
whose shadow is used to record the
changing position of the Sun.
BABYLON and SUMERIA 3000BC
• The astronomers of Babylon
were a special group of
scribes who observed the
movements of the stars and
planets. The astronomers had
many different
responsibilities. They
recorded their observations
about the daily, monthly and
yearly position of the stars and
planets. They advised the king
about how their observations
affected the calendar. And
they advised the king about
how omens seen on earth or in
the skies might effect future
events.
Newly translated Babylonian texts indicate that
positions and motions of the stars and planets
were calculated instead according to complex
equations inherited from the Sumerian
civilization. The Babylonians seem not to have
understood the theoretical basis of these formulas,
only how to use them.
The Sumerians had even more exact knowledge of
the solar system and its place in the universe than
their Babylonian heirs, whom they predate. Their
calendar, devised as early as 3000 B.C., is the
model for our calendar today, and they evidently
understood a number of more arcane astronomical
matters.
STONEHENGE
ENGLAND
2900 BC
Was used to
identify the
first day of
summer.
Ancient astronomers
could use it like a
giant gunsight to
determine when
the sun was rising
in a certain
direction.
EGYPTIAN Astronomy
Accurate
calendars
2400 BC
The Aztec “ Sun Stone”
Calendar of the Aztec people
of Pre-Columbian Mexico.
Stone's year of creation,
1479 CE.
Measures about 3.6
meters (12 feet) in
diameter, 1.22 meters (4
feet) in thickness and
weighing
24 tons,
[
Center of the Yucatán Peninsula
present-day Mexico.
"El Caracol"
at Chichén
Itzá --an
observatory
of the Maya
and Toltec.
The Maya
were expert
skywatchers
Buildings
aligned with
solstices,
equinoxes,
the moon, or
planets.
The Aztec calendar
wheel is represented by
13 months of 20 days
each, as determined by
the movement of the
Sun, Moon, and stars.
©Library of Congress
Aristotle
300 BC
• Famous Greek
philosopher
• Logic thinking
• Scientific teachings
used for over 1000
years
Earth, Water, Air, Fire,
Aether, which is the divine substance that makes up
the heavenly spheres and heavenly bodies (stars and planets).
Each of the four earthly elements has its natural place. All
that is earthly tends toward the center of the universe, i.e., the
center of the Earth. Water tends toward a sphere surrounding
the center. Air tends toward a sphere surrounding the water
sphere. Fire tends toward the lunar sphere (in which the
Moon orbits). When elements are moved out of their natural
place, they naturally move back towards it. This is "natural
motion"—motion requiring no extrinsic cause. So, for
example, in water, earthy bodies sink while air bubbles rise
up; in air, rain falls and flame rises. Outside all the other
spheres, the heavenly, fifth element, manifested in the stars
and planets, moves in the perfection of circles.
Ptolemy
(c.85-c.165)
GREEK
A
ASTRONOMER
Believed the planets
and sun orbit the
Earth.
GEOCENTRIC“Earth Centered”
The order: Mercury, Venus, Sun,
Mars, Jupiter, Saturn. This system
became known as the Ptolemaic
system.
Copernicus (1473-1543)
the founder
of modern
astronomy
His theory had
the sun in the
center of the
solar system
asserted that the earth
rotated on its axis once
daily and traveled around
the sun once yearly:
HELIOCENTRIC“Sun Centered”
http://www.polaris.iastate.edu/Even
ingStar/Unit2/unit2_sub2.htm
BRAHE 1546-1601
• Made an extremely
accurate star
catalogue of over
1000 stars.
• He showed the
moons orbit is not
a perfect circle.
KEPLER (1571 -1630)
realized that the orbits
of the planets were
not circles, but instead
"flattened circles"
called ellipses
GALILEO
1564 to 1642
Crafted his own telescope
Discovered:
that our Moon has craters,
Jupiter has its own moons,
the Sun has spots
Sir Isaac Newton (1642- 1727)
• Defined the Laws of Motion
and Universal Gravitation.
• Now our solar system makes
sense!