The Universe and the Big Bang
The Big Bang theory says the universe began about 13.8 billion years ago from a hot, dense state and has been expanding ever since.
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The Big Bang theory says the universe began about 13.8 billion years ago from a hot, dense state and has been expanding ever since.
- Red-shift shows galaxies moving away
- Cosmic background radiation is evidence
- The universe contains billions of galaxies
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is The Universe and the Big Bang?
Within Physics, which covers forces, energy, waves, electricity, magnetism, light and space explained through motion and experiments, this topic explains The Universe and the Big Bang. Physics topics explain how things move, push, heat up and carry energy, so each one here pairs a definition with a live model you can change.
Check that you can explain The Universe and the Big Bang in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding The Universe and the Big Bang explains how the physical world behaves, from sport and transport to electricity and medicine.
The Universe and the Big Bang in detail
The Big Bang theory says the Universe began about 13.8 billion years ago from an extremely hot, dense state and has been expanding ever since. Evidence includes the redshift of light from distant galaxies, showing they are moving away, and the cosmic microwave background radiation, the faint afterglow of the early Universe.
The more distant a galaxy, the faster it recedes, as stated by Hubble's law. Observations of the way galaxies rotate suggest dark matter, and the accelerating expansion suggests dark energy. Cosmology combines observation and theory to test models of how the Universe began and how it may end.
How the interactive helps you understand The Universe and the Big Bang
Watch the timeline in the interactive. Use any sliders or buttons it offers to change the values and see how the timeline responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of The Universe and the Big Bang.
Real-life uses and examples
- Answer “explain” questions by linking The Universe and the Big Bang to a clear cause and effect.
- Predict what a ball, car or circuit will do with The Universe and the Big Bang before you do the calculation.
- Explain everyday devices, such as brakes, lifts or chargers, using The Universe and the Big Bang.
Common mistakes to avoid
- Forgetting that some quantities, such as force or velocity, also have a direction.
- Mixing up The Universe and the Big Bang with a related quantity that has different units.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about The Universe and the Big Bang
What is The Universe and the Big Bang?
The Big Bang theory says the universe began about 13.8 billion years ago from a hot, dense state and has been expanding ever since.
What are the most important points about The Universe and the Big Bang?
The main points are: Red-shift shows galaxies moving away; Cosmic background radiation is evidence; The universe contains billions of galaxies.
Why is The Universe and the Big Bang useful?
Understanding The Universe and the Big Bang explains how the physical world behaves, from sport and transport to electricity and medicine.
How can I practise The Universe and the Big Bang?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to The Universe and the Big Bang?
Related topics in Physics include Rotational Motion and Torque, Capacitors and Charge Storage, Alternating and Direct Current.