The Ancient Mystery of the Planets

The Ancient Roots of Science

5 planets are visible by eye from Earth

“Planet” is from the Greek word for “wanderer”

The planets generally drift from west to east relative to the stars

BUT sometimes they appear to do something strange…

“retrograde motion”

“prograde motion”

Retrograde motion is only apparent

What’s really happening

Show Movie…

Why did the ancient Greeks reject the heliocentric model?

“Parallax” is much to small to measure without modern telescopes

The Ancient Roots of Science

DengFeng, China

Stonehenge, United Kingdom

Chichen Itza, Mexico

Practical uses of astronomy

To ancient people, the sky was both a clock and a calendar

The orientation of the waxing crescent moon could be used to predict the rainy season in central Nigeria

The days of our week were originally named for the “wanderers”

Time can be told during the day using the Sun’s position

Vrihat Samrat Yantra, a Jantar Mantar in Jaipur, IndiaThe world’s largest sundial, marked in increments of 2 seconds!

At night the Egyptians used a “star clock”

It told where various stars could be seen at different

times of night throughout the year.

Many cultures built structures to mark specific astronomical occasions

Stonehenge

Stonehenge, built in stages over 1200 years, hasalignments with many astronomical events.

It was also used as a burial place for the elite

This lane is now known to have been a naturally occurring stone

path or lane

Sun Stonehenge Location: W 1°49'34.0", N51°10'44.0", 100m Date Begin Rise Az. Transit Alt. Set Az. End (UT1) Astron. Astron. Twilight Twilight h m h m ° h m ° h m ° h m2015 Dec 10 (Thu) 05:57 08:00 127 12:00 16S 16:00 233 18:02 2015 Dec 11 (Fri) 05:58 08:01 127 12:00 16S 16:00 233 18:02 2015 Dec 12 (Sat) 05:59 08:02 127 12:01 16S 16:00 233 18:02 2015 Dec 13 (Sun) 06:00 08:03 127 12:01 16S 16:00 232 18:02 2015 Dec 14 (Mon) 06:01 08:04 128 12:02 16S 16:00 232 18:03 2015 Dec 15 (Tue) 06:02 08:04 128 12:02 16S 16:00 232 18:03 2015 Dec 16 (Wed) 06:02 08:05 128 12:03 16S 16:00 232 18:03 2015 Dec 17 (Thu) 06:03 08:06 128 12:03 16S 16:00 232 18:03 2015 Dec 18 (Fri) 06:04 08:07 128 12:04 15S 16:01 232 18:04 2015 Dec 19 (Sat) 06:04 08:07 128 12:04 15S 16:01 232 18:04 2015 Dec 20 (Sun) 06:05 08:08 128 12:05 15S 16:01 232 18:05 2015 Dec 21 (Mon) 06:05 08:09 128 12:05 15S 16:02 232 18:05 2015 Dec 22 (Tue) 06:06 08:09 128 12:06 15S 16:02 232 18:06 2015 Dec 23 (Wed) 06:06 08:10 128 12:06 15S 16:03 232 18:06 2015 Dec 24 (Thu) 06:07 08:10 128 12:07 15S 16:03 232 18:07 2015 Dec 25 (Fri) 06:07 08:10 128 12:07 15S 16:04 232 18:07 2015 Dec 26 (Sat) 06:08 08:11 128 12:08 16S 16:05 232 18:08 2015 Dec 27 (Sun) 06:08 08:11 128 12:08 16S 16:06 232 18:09 2015 Dec 28 (Mon) 06:08 08:11 128 12:09 16S 16:06 232 18:09 2015 Dec 29 (Tue) 06:08 08:11 128 12:09 16S 16:07 232 18:10 2015 Dec 30 (Wed) 06:09 08:11 128 12:10 16S 16:08 232 18:11 2015 Dec 31 (Thu) 06:09 08:11 127 12:10 16S 16:09 233 18:12

When people say“The Sun shines through this opening only on the morning of the solstice”,

they’re being less than informed.

Callenish, Isle of Lewis, Scotland

Newgrange, Ireland

Chichen Itza,Yucatán, Mexico

El Caracol – alignments with the rising and setting of Venus

El Castillo – same number of steps as days in a year

Alignments with the equinoxes

Great Kiva in Chaco Canyon

The Sun Daggerin Chaco Canyon

Chinese astronomers have been recording astronomical observations

for at least 5000 years

Machu Picchu includes alignments with summer and winter solstice sunrises

Micronesia – stars for navigation

Do the structures built by ancient peoples for observing celestial events prove that they were doing science?

A. No. There was no “science” before Isaac Newton.

B. Yes. Observing the stars is scientific.

C. No. Observation is only the first step in the scientific process.

D. Yes. Since they were able to detect the solstices, they were doing science.

Astro-Cash Cab!

Jeffrey Crawford

Nick Kirpes

Curran Grant

Tyler Zito

LeKisha Sanchez

1) How much parallax does the closest star (other than our Sun!) display?

less than one arcsecond

about 20 arcseconds

around 1 arcminute

The closest star does not show parallax,as far as modern instruments can detect

2) In which direction is the “normal” motion of the planets relative to the stars?

East-to-west

West-to-east

They don’t actually move

3) True or False?

The biggest drawback to a sundial is it’s poor accuracy.

4) True or False?

Before the invention of mechanical clocks, it was not possible to tell the time at night