Discipline
Cosmology
Lessons across the journey that lean on cosmology, in the order they appear in the story.
- 1.1 Was the Big Bang an explosion?Draft
The Big Bang was not a blast at a point in empty space. It was the whole universe, everywhere at once, hot and dense and beginning to expand.
- 1.2 The first three minutesDraft
How quarks became protons and neutrons, and how the first nuclei formed before the universe was twenty minutes old.
- 1.3 Why is the night sky dark?Draft
A dark night sky is evidence that the universe has a finite age and is expanding.
- 1.4 The afterglowDraft
The cosmic microwave background, the oldest light there is, and what its faint ripples tell us.
- 1.5 How we knowDraft
The three pillars of evidence for the Big Bang, and how each one could have proved it wrong.
- 1.6 The Dark Ages and the first lightDraft
A hundred million years of darkness, and then the first stars switch on.
- 1.7 Open questionsDraft
Dark matter, dark energy and inflation: what the standard model of cosmology cannot yet explain.
- 2.1 Gravity versus pressureDraft
How a cloud of gas collapses, heats and ignites.
- 2.3 The lives of stars, sorted by massDraft
Why a star's mass decides everything: how long it lives, how it dies and what it leaves behind.
- 2.4 GalaxiesDraft
Cities of stars, dark matter and the cosmic web.
- 2.5 Reading starlightDraft
Spectra, distances and the cosmic distance ladder: how we measure things we can never visit.
- 3.1 Where the elements come fromDraft
Stellar nucleosynthesis: how stars build carbon, oxygen and iron.
- 3.2 Making goldDraft
Supernovae and neutron-star mergers, the violent events that make the heaviest elements.
- 3.5 Molecules in spaceDraft
Dust, ice and organic molecules between the stars.
- 3.7 Are you really made of stardust?Draft
The famous claim, tested element by element.
- 9.5 Leaving EarthDraft
Space is one of the most valuable things we do, and almost all of its value points back at Earth.
- 9.6 The deep futureDraft
Earth has about a billion years of biosphere left, not five, and that is only the first paragraph.