Drag to turn it, scroll or pinch to zoom. The slider beneath it runs a whole lifespan in seconds — every value computed from the name and the planting minute.
Type is an outcome, not a setting. Mass, spin and environment are drawn at planting; the Hubble class is whatever they and the merger history produce. Mass quenches a galaxy from within, environment strips it from outside — which is how a lenticular keeps its disc.
Globular clusters follow halo mass, not stellar mass — about one per 7×109 solar masses of halo — which is why a giant can hold eighty times the Milky Way's on four times the stars. They form in the first burst, arrive again aboard swallowed satellites, and outlive everything else here: the knots still in the halo after the galaxy has gone quiet are the oldest thing it owns. At a true scale each would be a thousandth of a pixel, so they are drawn far larger than they are, and the count saturates in the picture past 900 while the readout keeps the real number.
Derived from bulge mass by the Häring–Rix relation. The horizon is about a ten-millionth of the disc radius, so it is never drawn — what you see during a merger is the companion's accretion knot.
Lifespan is immutable once a galaxy is planted — changing it here plants a different one. The seed is never stored: it is mix(fnv1a(name | birth-minute)), re-derived on every load, which is why a galaxy can be recovered from a remembered name and an approximate time. Star orbits run on the wall clock and are identical for every galaxy, so a ten-year galaxy is as watchable as a one-month one.