Grade 9 Science: Dec. 17 – Constellations

Learning Goals:

Understand some cultural significances of astronomy.
Understand how to describe were celestial objects are in the sky.

Success Criteria:

You can describe how the solstice, equinox and constellations are significance in different cultures.
You can find certain constellations in the sky. You can describe where they are on the celestial sphere.

Handout:

Constellations

Today we started by discussing how people from different cultures saw different time of year or different things in the sky as significant.

The shadows create the shape of a serpent on the side of a Mayan pyramid during the equinox.

Stonehenge was built to align with the setting sun on the exact day of the summer solstice.

The Egyptians built their pyramids with air shafts that aligned with significant stars.

People throughout history have named and assigned meaning to the stars. They are grouped together in what are called constellations. These constellations change over the course of 100 000 years due to the motion of individual stars.

The Big Dipper is an example of a constellation. In fact, it's actually part of a larger constellation called Ursa Major.

It is important to note that these constellations are arbitrary. Some people might see a hunter called Orion, while the some Aboriginal people call the same set of stars a canoe.

One way to describe where things are in the sky is to use angles called azimuth and altitude.

Another way is to use the celestial sphere.

An imaginary sphere around the Earth where we can project all celestial objects.

While the stars will be stationary on the celestial sphere over the course of our lifetime, planets and the sun appear to move past the stars due to our own motion of the Earth.

People name different time of the year after certain constellations depending on where the sun is. These twelve constellations are called the Zodiac.

Sometimes planets appear to move backwards in their path in a phenomenon called retrograde motion. This happens because the Earth moves faster than Mars.

Retrograde motion of mars.

We then made our very own star finders! You can download and make your own versions from various sites such as these:

Those of you who are more high tech can download apps on your phones to do the same thing. Here is a fun one that finds planets for you, but there are many more that do the same thing.