Tideglass Studio
The eight stages

Stage 3 of 8

Boulder

Gains: Inertia

The most dangerous size to be. Survive it, and gravity turns to your side.

Now you are a boulder, and you have reached the most dangerous size a young world can be.

A lone meter-sized boulder facing the gas drag of the disk.

The meter-size barrier

Growing has a trap in it. At about a meter across, a body feels the gas drag so strongly that it should spiral into the star and burn within a human lifetime. Astronomers call it the meter-size barrier, and for a long time no one could explain how anything survives it.

A dense swarm of boulders collapsing together under its own gravity.

Crowds become worlds

You survived the way boulders do: in a crowd. Where the gas piled pebbles and boulders thick enough, the whole clump's own gravity pulled it together faster than the star could steal it away. A swarm collapsed in one motion. You came out the far side heavier, and for the first time, holding your own line.

True things

  • The meter-size barrier is a real puzzle: simple models say meter rocks should fall into the star.
  • The streaming instability lets swarms of pebbles collapse straight into kilometer bodies.
  • Inertia is just mass refusing to be moved. The more you gather, the harder you are to push.