Introduction to Astronomy

What it’s All About?

El Caracol, Observatory, Chichen Itza, Yucatan, Mexico (1000 A.D.)

Welcome To Astronomy!!!

1.) Rules: Follow Them!2.) Text: Explorations and Starry Night3.) Assignmentsa. Turning them inb. Time limits (1 week)4.) Projects and Presentation(2)5.) Expectations6.) About Me!

Warm Up

1. Give three reasons that ancients studied the heavens.

2. What type of science is astronomy?

AstronomyAstronomy 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.

ScaleScale 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 AstronomyHumans 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 12-month calendar with each month lasting 30 days (based on the lunar cycles). The astronomer-priests 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 AstronomyThe 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 BritainCertainly 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 Kukulcán-Quetzalcóatl, 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 N-S 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