The Big Bang
This scientist is credited with discovering that the universe is expanding.
Edwin Hubble
The name of the galaxy that contains our Solar System.
The Milky Way
This sphere includes all living organisms on Earth.
The biosphere
This natural effect — amplified by human activity — keeps Earth warm enough to support life.
The greenhouse effect.
This competition between the USA and USSR to achieve milestones in space during the Cold War is known as…
The Space Race.
This faint microwave radiation fills the entire universe and is considered the 'afterglow' of the Big Bang.
Cosmic Microwave Background (CMB) radiation
On a Hertzsprung–Russell diagram, stars are plotted using these two properties.
Temperature (spectral class) and luminosity (absolute magnitude)
The ozone layer, which protects life from UV radiation, is found in this atmospheric layer.
The stratosphere.
This process — where climate models are tested against known historical data to check accuracy — is called…
Hindcasting.
Fragments of old satellites and rocket stages that orbit Earth and pose a hazard to spacecraft.
Space debris (orbital debris)
A larger red shift measurement indicates a galaxy is doing this compared to one with a smaller red shift.
Moving away faster / is more distant
Describe the difference between absolute magnitude and apparent magnitude.
Absolute magnitude is the true intrinsic brightness of a star measured at a standard distance of 10 parsecs. Apparent magnitude is how bright the star looks from Earth, which depends on both its intrinsic brightness and its distance from us.
Geological time is divided into large units called eons. Name the four eons that make up Earth's history.
Hadean, Archean, Proterozoic, Phanerozoic
Using the data trend of CO₂ rising from 338 ppm (1980) to 414 ppm (2020), explain what this tells us and why it matters.
CO₂ has increased by 76 ppm over 40 years — a consistent upward trend correlating with industrialisation. Higher CO₂ means more infrared radiation is trapped, enhancing the greenhouse effect and driving global temperature increases linked to climate change.
Describe one environmental impact of space exploration that is often overlooked.
Rocket launches emit CO₂, soot (black carbon) and water vapour into the upper atmosphere, where they can linger and affect the ozone layer. Space debris also poses long-term risks to satellite infrastructure that modern society depends on.
This is a recognised limitation of the Big Bang Theory — something it cannot currently explain.
What existed or happened before the Big Bang (the 'singularity' problem)
Describe how Indigenous Australians demonstrate sophisticated astronomical knowledge through their use of the night sky.
Indigenous Australians have used the sky for over 65,000 years to navigate, track seasons, predict animal movements and food availability, and pass on cultural law and stories. Dark constellations (using the dark patches of the Milky Way) are a unique feature of Aboriginal astronomy not common in Western traditions.
Name and describe the five main layers of the atmosphere from lowest to highest.
Troposphere (weather, most life-supporting gases), Stratosphere (ozone layer, UV absorption), Mesosphere (meteors burn up here), Thermosphere (aurora, satellites), Exosphere (outermost, merges with space).
Describe two strategies to mitigate climate change and explain the difference between mitigation and adaptation.
Mitigation reduces the cause: e.g. transitioning to renewable energy (reduces CO₂ emissions) or reforestation (increases carbon sinks). Adaptation responds to impacts: e.g. building sea walls or developing drought-resistant crops. Mitigation addresses the problem at its source; adaptation manages consequences that can no longer be avoided.
Explain how satellites have transformed life on Earth, providing at least three specific examples.
GPS navigation (transport, emergency services, agriculture). Weather forecasting (satellites monitor cloud patterns, cyclones, sea surface temperatures). Global communications (internet, phone calls, TV broadcasts). Earth observation (monitoring deforestation, ice loss, crop health, disaster response).
Using red shift and CMB together, construct a logical argument for why the universe began in an extremely hot, dense state.
Red shift shows all galaxies are receding — running time backwards implies everything was once in the same place. CMB is uniform low-energy microwave radiation that matches the predicted 'cooling glow' of a once-hot dense universe that has since expanded and cooled over ~13.8 billion years. Together they support a single explosive origin.
Compare and contrast the full life cycles of a low-mass star and a high-mass star, starting from a nebula.
Both begin in a stellar nebula → protostar → main sequence star. Low-mass: expands into a red giant → sheds outer layers as a planetary nebula → leaves a white dwarf. High-mass: expands into a red supergiant → explodes as a supernova → leaves either a neutron star or (if massive enough) a black hole.
Explain how the carbon cycle, atmospheric composition and temperature are interconnected, and what would happen if one part of the cycle was significantly disrupted.
Carbon cycles through photosynthesis (removes CO₂), respiration/decomposition (returns CO₂), ocean absorption, and volcanic outgassing. CO₂ concentration determines the strength of the greenhouse effect — more CO₂ traps more heat, raising temperature. If deforestation removes large amounts of plant life, less CO₂ is absorbed, concentrations rise, temperatures increase, altering precipitation patterns and disrupting the water cycle — cascading through all spheres to threaten biodiversity.
Describe the ice-albedo feedback loop and explain how it amplifies global warming.
Ice and snow reflect sunlight (high albedo). As temperatures rise, ice melts, exposing darker ocean or land surfaces that absorb more heat. This raises temperatures further, causing more melting — a self-reinforcing (positive) feedback loop that accelerates warming.
Some argue space exploration is a luxury humanity cannot afford given climate change and global poverty. Others say it is essential for our long-term survival. Develop your own justified position on this debate.
A strong answer should: state a clear position; use specific evidence (e.g. satellite data improves climate monitoring; space tech spin-offs benefit medicine and agriculture; Mars as a long-term backup for humanity); acknowledge the counterargument (cost, equity, environmental impact of launches); and conclude with a nuanced justification — e.g. space exploration should continue at a scaled level that prioritises Earth-monitoring and technology development, with a binding international framework to reduce environmental and debris impacts.