Run · The Universe Pulls Apart

Settle in title

Season 1 · Session 10

The Universe Pulls Apart

Space itself is stretching, and the stretch is speeding up.

Prompt deck —

Use ↓ / ↑ to move between movements. → / ← steps the prompts. Space reveals on the wall.

Host notes, laptop only

Framing

We're not asking the room to solve dark energy. Nobody has. We're closing the season on the honest edge of what's known, and sitting with how much of reality is still open.

Opening question (Settle in)

If everything is flying apart, what is doing the pushing?

The precise version (Watch)

The expansion of the universe is described by the scale factor a(t), which gives the relative size of the universe at time t. The Hubble parameter H(t) = ȧ/a describes the rate of expansion. Edwin Hubble's 1929 observations showed that galaxy recession velocities increase proportionally with distance (v = H₀d), implying expansion. Today's Hubble constant H₀ is measured at approximately 67–73 km/s/Mpc (a tension between CMB-derived and distance-ladder values is an active research area). The expansion is not galaxies moving through space. It is space itself stretching. Bound systems (galaxies, solar systems, atoms) do not expand. Only the metric between unbound systems grows.

If it wobbles

Confidently wrong — Don't correct 'everything's flying out from the centre.' Ask, 'Where's the centre, then? Every galaxy sees all the others receding from it. What kind of expansion does that?'
Dead silence — Open the scale. 'About 95% of the universe is stuff we can weigh but can't name. We're the 5% that understands. What does that sit like for you?'
Runaway debate — Pull back. 'Hold the theories of dark energy. Let's first agree on what the supernova data actually showed.'
Tipping into dogma — Name it. 'This is the one place a confident story sneaks in. The honest move is to stay certain about the measurement and open about the cause. Let's stay there.'

Wrap — close on (LOCKED)

How do you feel about this science and its understanding of reality?

The Universe Pulls Apart

Facilitator hotkeys