Transcript Introduction to Astronomy - Journigan-wiki

Introduction to Astronomy
El Caracol, Observatory, Chichen Itza, Yucatan, Mexico (1000 A.D.)
What it’s All About?
Welcome To Astronomy!!!
1.) Rules: Follow Them!
2.) Text: Explorations and Starry Night
3.) Assignments
a. Turning them in
b. Time limits (1 week)
4.) Projects and Presentation(2)
5.) Expectations
6.) About Me!
Warm Up
1. Give three reasons that ancients studied
the heavens.
2. What type of science is astronomy?
Astronomy
Astronomy is about the study of the
heavens and all the things that make up
our Universe. It is specifically about the
Earth’s place within the Universe.
Scale
Scale refers to your point of view. You
can look at things very closely or you can
look at things from very far away.
Astronomy looks at things from both points
of view.
Atom
Andromeda Galaxy
Observational Science
Astronomy is an
observational science (for
the most part) and not an
experimental science.
We can not take galaxies
or solar systems and
change them to see what
will happen. We know
what we know about our
Universe from what we
see or have seen.
Cultures and Astronomy
Humans have been studying the stars
(both systematically and unsystematically)
since the dawn of man. On Earth, night is
the day’s counter-balance and represents
half of our terrestrial experience.
Night sky, June 4, 2004
Why Did Ancients Study the Heavens?
The night sky is mysterious! You only
have to look for a few hours or days to
notice that there is a regularity to what you
see at night.
Nanjing star watching platform, Sung Dynasty (1200 A.D.)
Why Did Ancients Study the Heavens?
Besides the mystery, there are some very
practical reasons for looking up at night.
The stars go through cycles. Some of
these cycles last hours, some days, some
years and some lasting billions of years.
Why Did Ancients Study the Heavens?
Early Chinese astronomers looked for
portents or harbingers of change for the
country and its leader. Chinese records
show observations of comets made 2
millennia ago.
Comet Hale-Bopp (1997)
Chinese Observations
Chinese observations of Halley’s comet
date back to 240 BCE. The Mawangdui
silk, a 'textbook' of comets and the various
disasters associated with them, was
compiled sometime around 300 B.C.
Egyptian Astronomy
Egyptians followed a 12month calendar with each
month lasting 30 days
(based on the lunar
cycles). The astronomerpriests were well aware of
the 5-day discrepancy.
For ritual reasons they
followed each year with a
5-day feast to round out
the year.
Egyptian Astronomy
• This “sothic cycle” lasted for 1,460 years
meaning that each season cycled through twice
during this period. Sothic refers to the periodic
rising and setting of the star Sirius. These
records called “heliacal risings” were often
carved into Pharaoh's coffins. These records
have enabled paleontologists to accurately place
the Egyptian dynasties throughout history. The
beginning of the last cycle began in 1499.
Egyptian Astronomy
The Egyptian year contained 3 seasons:
the flooding, the subsistence of the river
and the flooding. Astronomer-priests were
very powerful in Egypt because (using the
rising of Sirius) they could accurately
predict the flooding of the Nile.
Orion Correlation Theory
The Orion correlation theory (or Giza–Orion correlation
theory ) is a hypothesis in pyramidology. Its central claim is
that there is a correlation between the location of the three
largest pyramids of the Giza pyramid complex and the three
middle stars of the constellation Orion, and that this
correlation was intended as such by the builders of the
pyramids. The stars of Orion were associated with Osiris, the
sun-god of rebirth and afterlife, by the ancient Egyptians.
Depending on the version of the theory, additional pyramids
can be included to complete the picture of the Orion
constellation, and the Nile river can be included to match with
the Milky Way galaxy
Ancient Astronomy in Britain
Certainly the most famous of ancient
astronomical tools in Stonehenge in Great
Britain. It was built (by druids) in three
stages beginning in 2800 B.C. It is one of
approximately 900 megalithic circles
located on the islands.
Newgrange
Newgrange is an
underground tomb
located in Ireland.
Several passageways at
created into the tomb
that are illuminated (for
17 minutes) only on the
first day of the winter
solstice. It was built
around 3200 B.C., 600
years before the Giza
pyramids in Egypt.
Native American Astronomy
The “Sun Dagger” was created my the
Anasazi. Designed by pueblo indians in
southern North America and northern
Central America around 1,000 A.D., the
sun dagger marks summer and winter
solstices as well as the vernal (spring) and
autumnal (fall) equinoxes.
Caracol (snail) Tower
Caracol tower is located in the former
Mayan city of Chichén Itzá , located on the
Yucatan peninsula in southern Mexico.
Caracol was created for the observation of
the planet Venus which represented the
celestial manifestation of KukulcánQuetzalcóatl, the Mayan’s winged serpent
god. Because the tower was partially
destroyed, its other celestial alignments
will never be known.
Images of Caracol Tower
Temple at Karnak, Luxor, Egypt
Temple at Karnak, Luxor, Egypt
• Certain alignments correspond to the
summer solstice sunset and the winter
solstice sunrise.
Pyramid of Khufu
•
•
•
Shafts from the King's chamber point to
the location of Polaris 5,000 years ago
and former position of Orion's belt.
The significance of these things is in
their mythology.
The pyramid is also aligned perfectly NS and E-W.
Pyramid of Khufu
Gotland Grooves, Sweden
There are about 3,600 known grooves in stones in
Gotland. 700 are in the bedrock, which is limestone, and
the rest in about 800 stones. The length of the grooves
varies from about 0.5 to 1 meter. They are between 5 cm
to 10 cm wide and 1 cm to 10 cm in depth.
They are shaped as though they were made by a tool
fixed on a pendulum, the cross section of the length of
each mark being in most cases part of a circle.
The most important feature of the grooves is alignment.
A study of 1,256 grooves showed that they are aligned
with certain positions of the celestial bodies, apparently
the sun or the moon.
Big Horn Medicine Wheel, Wyoming
The Big Horn Medicine Wheel is a circle created
from stones. Its diameter is about 80 feet and it
contains 28 spokes. Six stone cairns are
arranged around the circle. If you stand or sit at
one cairn looking towards another, you will be
pointed to certain places on the distant horizon.
These points indicate where the Sun rises or
sets on summer solstice and where certain
important stars rise heliacally, that is, first rise at
dawn after being behind the Sun.
Big Horn Medicine Wheel, Wyoming
These points indicate where the Sun rises or sets
on summer solstice and where certain important
stars rise heliacally, that is, first rise at dawn
after being behind the Sun.
• The number 28 is sacred to some of the Indian
tribes because of its significance as the lunar
month. In Bighorn's case, could the special
number 28 also refer to the heliacal or dawn
rising of Rigel 28 days past the Solstice, and
Sirius another 28 past that? No one knows!
Big Horn Medicine Wheel, Wyoming
Astronomy Webquest
http://www2.yk.psu.edu/~mer7/
astronomytimeline.htm#process
Homework
Chapter 1-page 8, problems 6 & 7.
page 13, problems 11 & 12
Chapter 2- page 29, problems 1-3.
Page 30, problems 4-9.
Page 32, problems 14a-h.
Page 33, problems 15 & 16
Page 34, problems 17 & 18.
Page 39, problems 31 & 32