What is drawn to scale
The habitat is built from the same numbers as the simulator: the barrel's diameter and length, the two hemispherical end caps, the light tube on the axis, and outside, the propellant drum and the laser sail. The drum sits behind the aft cap; with a laser sail it sits ahead of the bow, between the habitat and the sail, because the sail tows the ship and the brake engine has to point forward. Distances, gravity and air pressure in the readout are worked out for the spot you are standing on.
Not to scale: the stars are points at their catalogue brightness, and the light tube is drawn as bright as a screen allows, not as bright as it would be.
The light tube
There is no sun inside. A tube of light runs along the axis from hub to hub and follows a 24-hour day, with a short dawn and dusk and a dim night. The light on every surface is worked out exactly for a long glowing line: ground facing the axis gets the most and slopes facing along the barrel get about half. The light dims a little toward the ends of the barrel, then grows again up the end caps, which curve in toward the tube: near the hubs they get two to five times the light of the barrel floor.
At night the tube dims to about a thousandth of its daylight: deep dusk, still about a hundred times brighter than a full moon. The view brightens as your eyes adapt to the dark, so the land stays readable and the lit windows glow.
The air
The air turns with the hull at one temperature, 20 °C, so spin gravity holds it against the floor the way Earth's gravity holds our atmosphere. Its density falls toward the axis over a scale height of 8.6 km at 1 g, the same law the simulator uses for the air's mass. Light from the tube scatters once on its way to your eye: blue from the gas, white from the haze.
So the size of the habitat changes the sky. In a cylinder a few kilometres across the air is nearly as thick at the axis as at the floor, and the far side looks hazy and blue. In one more than about 80 km across (at 1 g) the axis has less than a tenth of the floor's air, and you look up through a thin bright layer into a dark, almost airless middle.
Outside
Between the stars nothing lights the hull: seen from outside it would be almost black, apart from its windows and the drive. Here it is lit from one side by an illustrator's light so its shape can be read. The hull turns at its true rate, sped up by the time warp you choose.
The land
How the floor is shared between homes, farms, forest and water, and where those numbers come from, is listed here once the land plan is in.
Moving around
- Inside
- Drag
- Look around: grab the view and pull it.
- W A S D or arrows
- Walk. Hold Shift to go faster.
- Space E / Q C
- Fly up toward the axis, or down. Back on the floor you walk again.
- Mouse wheel
- Rise or sink. Pinching on a trackpad moves you forward.
- J L / I K
- Turn left or right; look up or down.
- Right-drag
- Slide over the ground without turning.
- Double-click
- Glide to that spot on the floor, the far side included.
- Outside
- Drag
- Turn around the ship.
- Right-drag
- Slide the view sideways.
- Mouse wheel
- Zoom, from beside the hull out to the whole laser sail.
- A D / E Q / W S
- Around, over and under, closer and farther.
- Touch
- One finger
- Look around inside; turn around the ship outside.
- Pinch
- Move forward or back inside; zoom outside.
- Two fingers
- Drag sideways to move inside, or to slide the view outside.
- Two fingers up or down
- Rise toward the axis, or sink back to the floor.
- Double-tap
- Glide to that spot on the floor.
- Anywhere
- 1 … 9, 0
- Jump to the viewpoints in the order they are listed.
- H
- Hide the controls for a clear view, or bring them back. The eye button beside ? does the same.
- ? / Esc
- Open or close this page.