Teaching sequence

Lesson objective

In this lesson students review the steady state and Big Bang theories about the universe and consider how evidence supports the latter. They explore recent discoveries that propose the existence of dark matter and dark energy.


Ask the students to describe what they know about the origin of the universe. Acknowledge that different cultures have their own stories. Explain that scientific theories about the origin of the universe were developed based on observations and data but the theories have changed over time as new evidence has become available.

Teacher note: For more information on these scientific theories see Background information.


  1. Ask students to read the article ‘Origin of everything: hot bang or ageless universe?’ from the 1955 Cosmic Times, summarise the main ideas of the two theories presented and explain how evidence is used to support each theory.
  2. Ask students to read the article ‘Murmer of a bang’ from the 1965 Cosmic Times and identify what new evidence has been presented and how that evidence supports one theory over another.
  3. Tell students that today the Big Bang theory is the broadly accepted theory that best explains the origin and evolution of the universe.
  4. Have students link to the Big Bang page on the NASA Science: Astrophysics website to:
    • read the information about the Big Bang
    • watch the video on the history of the universe
    • read the information about background radiation
    • watch the video showing how the structure of the universe evolved from the Big Bang.
  5. Explain that while the Big Bang theory postulates that 13.7 billion years ago not only matter, but also space and time burst into existence to form the universe, no one really knows how this occurred. Describe how scientists question what the fate of the universe will be. Will it continue to expand or eventually stop expanding and start to contract?


Describe how Australian astronomer Brian Schmidt was awarded the Nobel Prize in Physics in 2011 for his discovery (The High-Z SN Search) that the universe is continuing to expand at an accelerating rate.

View the video 2011 Nobel Prize: Dark energy that explains the findings of Brian Schmidt and his team.

Choose the most appropriate activity from Concepts for The Cosmic Engine (p 6) to model the expanding universe.

Lesson Resources


Student activities

Digital resources

Origin of everything: hot bang or ageless universe,
1955 Cosmic Times,
Goddard Space Flight Centre, NASA 

Murmer of a bang,
1965 Cosmic Times,
Goddard Space Flight Centre, NASA 

The big bang,
NASA Science: Astrophysics 

The High-Z SN Search,
RSAA Australian National University 

2011 Nobel Prize: Dark energy,
YouTube (1:39 min) 

Concepts for The Cosmic Engine,
Science Teachers' Workshop (PDF, 31.1 KB) (Link updated, 19 December, 2016.)

Extension activities

Crunch, rip or status quo? (Word, 323 KB)

Useful links

Astronomy theories,
Teachers’ Domain. Video (4:58 min) 

Concepts for The Cosmic Engine,
p 4–5, ATNF CSIRO (PDF, 31.1 KB). Big bang theory concepts to emphasise 

Explore: the big bang,
Harvard Smithsonian Centre for Astrophysics. Information 

How big is the universe? 
NOVA, Public Broadcasting Service. Latest theories on size of the universe 

Parameters of cosmology:
overview, WMAP, NASA. Information 

R9635 Map of the cosmic background radiation, NDLRN. Image 

Tests of big bang:
the CMB, WMAP, NASA. Discovery of cosmic microwave background 

What is the re-ionisation era? 
A schematic outline of the cosmic history, Caltech. Image 

Window to the universe: The Square Kilometre Array
 p 32–34, ska.edu.au (PDF, 5.7 MB). Teacher resource.  (9 December, 2016: Original resource no longer available, this copy made available via the Internet Archive's Wayback Machine.)