Generative Assets · №108 · Deep Time

Perihelion a seventy-six-year return

Once a lifetime the ice comes close enough to burn. The sun tears two tails from it — one of ionised gas, one of dust — and for a few weeks the dark holds a bright, streaming thing that points forever away from the star.

Ion tail · straight, anti-solar Dust tail · curved, trailing

Orbit notes

It spends a human life away, and a fortnight on fire.

01 · THE ELLIPSE

Kepler's law, drawn

The sun sits at one focus. Equal areas in equal times: watch the timing ticks bunch far out and spread near the sun — the comet loafs through aphelion and whips through perihelion.

02 · THE TAILS

Two, never one

Solar wind blows the ion tail dead straight away from the sun. Radiation pressure pushes heavier dust more gently, so it lags the orbit and curves. Both grow with heat and vanish in the cold.

03 · THE RETURN

1986, then 2061

No two returns run the same. The last close pass was 1986; the next is 2061 — seventy-five years, though the long-run mean is nearer seventy-six. Between them: the cold, the dark, and patience.

At aphelion it is a dead grey stone, further from the sun than Neptune. Then it falls, and catches light.

Watch the ephemeris climb as it nears the sun