Unit Context:

Humans have always been inspired by the universe. The movement of the Sun, stars, Moon and planets has been studied for centuries, and there is still so much unknown. Advances in technology have let us see further and further into space to discover more about how the universe began and what it is made of. 

There can be a certain feeling of insignificance as well as awe that people experience when they think about the enormous size of our expanding universe. In this chapter, you will learn about what can be observed in the night sky and what information can be gathered from stars and galaxies to find out about how it all began. 

Inquiry questions

Why have technological developments furthered our understanding of the universe?

How do dimmer stars live longer?

What evidence supports the Big Bang?

Student Learning Goals:

I can describe the key features of the universe. (Galaxies, Stars, Nebulae, Black holes, Neutron Stars)

I can outline the ways in which astronomers observe the universe.

I can use appropriate scales to measure distances in the universe.

I can identify that all objects in the universe exert gravitational attraction on all other objects in the universe that have mass.

I can use scientific evidence to outline how the Big Bang theory can be used to explain the origin of the universe and its age.

I can use scientific evidence to outline how the Big Bang theory can be used to explain the origin of the universe and its age.

I can discuss and outline possible future directions of astronomical research. 

Extension Activities:

• • • I can describe some recent contributions made by Australian scientists in the exploration and study of the universe.

    • I can describe the ways that Aboriginal Australians interpreted the night sky.

    • I can describe future directions in space exploration including colonisation of the Moon, Mars and perhaps other star systems

Early astronomers

The early astronomers relied on the naked eye to make observations about the positions of celestial objects and how they moved over time. Claudius Ptolemy was an astronomer from the second century who suggested that Earth was at the center of the universe. He proposed a geocentric model in which all celestial objects orbited around Earth. 

It is easy to see why he suggested this model, given that the Sun, stars and Moon all appear to rise in the east, follow a circular pattern while they are up, and then set in the west. 

There was one main problem with Ptolemy’s geocentric model. At different points in the year, the motion of the planets across the sky appears to go backwards for a few days. It is called retrograde motion and could not happen if the planets orbited Earth. 

In the early 1500s, Nicolaus Copernicus proposed a heliocentric model of the solar system, in which the planets revolved around the Sun.