Edexcel IGCSE Physics · Spec 8.3
Redshift & the Big Bang
Redshift and the evidence for the Big Bang theory.
Physics revision video
Redshift & the Big Bang
Prefer to watch on YouTube? Open this video on YouTube.
Spec 8.3
What you need to know
- Explain redshift
- Describe the evidence for an expanding universe
- Outline the Big Bang theory
Active recall
Quick check
Answer each question before opening the answer.
What is redshift and what does it show?
Light from distant galaxies is shifted to longer (red) wavelengths, showing they are moving away and the Universe is expanding.
How does redshift support the Big Bang theory?
More distant galaxies show greater redshift, so they move away faster — consistent with expansion from a single point.
Physics video companion
Keep your notes and exam practice together
The free Physics workbook follows every video in specification order.