This memory aid covers Memory Aids within Red Shift & Big Bang for GCSE Physics. Revise Red Shift & Big Bang in Space Physics for GCSE Physics with 13 exam-style questions and 12 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 10 of 14 in this topic. Use it for quick recall, then test yourself straight afterwards so the memory aid becomes usable in an answer.
Topic position
Section 10 of 14
Practice
13 questions
Recall
12 flashcards
🧠 Memory Aids
Red Shift Direction — "Red means Running Away"
Red = longer wavelength = source moving away. Think of a red flashing light on the back of a retreating ambulance — red light means going away from you. Red shift = galaxy running away.
Two Pieces of Evidence for Big Bang — "Red CMBR"
The two main pieces of evidence are: Red shift (galaxies moving apart — universe expanding) and CMBR (afterglow radiation from hot early universe). Remember them together as a pair: "Red and Warm" — Red shift shows expansion, CMBR shows the warmth that remains.
CMBR Temperature — "3 Degrees"
The CMBR temperature is about 2.7 K — just remember "nearly 3 degrees above absolute zero." It is incredibly cold because the universe has been cooling and expanding for nearly 14 billion years since the Big Bang.
Quick Check: State two pieces of evidence that support the Big Bang theory and briefly explain what each piece of evidence shows.
1. Red shift of galaxies: Almost all galaxies show red-shifted light, meaning they are moving away from us. More distant galaxies are receding faster. This shows the universe is currently expanding — which is consistent with it having originated in a Big Bang. 2. Cosmic Microwave Background Radiation (CMBR): Faint microwave radiation is detected from all directions in space at about 2.7 K. This is the cooled-down afterglow of the extremely hot early universe. It was predicted by Big Bang theory before it was discovered, making it very strong supporting evidence.