Cosmology & the Big Bang
📋 What it is
The universe began ~13.8 billion years ago and has been expanding — space itself stretching — ever since.
🗣️ Coach says
Cosmology tells the universe’s life story. Galaxies rushing apart and a faint heat-glow filling all of space point to a hot, dense start ~13.8 billion years ago. Crucially, it’s space ITSELF expanding, not an explosion thrown into empty space.
🧠 Memory hook
Big Bang = space itself expanding from a hot dense start, 13.8 billion years ago.
😂 Giggle
Why did Jupiter fail the diet?
It just had too much mass — and gas!
😲 Whoa!
The cosmic microwave background — the Big Bang’s leftover glow — fills the entire sky; a sliver of the static on old analog TVs was this ancient light.
✅ Quick check: Did the Big Bang explode matter out into pre-existing empty space?
Say your answer out loud first — then reveal.
No — space itself expanded everywhere at once from a hot, dense state; there was no "outside".
The Big Bang is the expansion of space, not a blast within it.
🪄 Trick question: Is there one spot in the sky where the Big Bang happened?
Careful — think it through, then reveal.
No — it happened everywhere at once; every point of space was part of it.
All of space was in the initial hot dense state.
🧪 Try it! (2 minutes)
Dot a balloon and inflate it — every dot moves away from every other, like galaxies in expanding space.