Elliptical Galaxy Simulator

Elliptical Galaxy

Ellipticity E3

Rotation strength 0.4

Old-star fraction 88%

Class

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Axis ratio b/a

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Edge velocity

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Stars shown

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How it works

Unlike a spiral, an elliptical galaxy has no arms or disk to trace — its light is smooth and featureless because it is built from stars orbiting on randomly oriented paths inside a spheroid, not confined to a thin plane. This model scatters thousands of stars using a centrally concentrated radial profile (dense core, sparse outskirts, the same shape real ellipticals show) and then flattens the whole star field along one axis to set its Hubble morphological class, from a near-round E0 to a strongly elongated E7.

b/a = 1 − 0.1·Eclass   (E0 round … E7 flattened)
v ∝ r  (rigid-body-like rotation, simplified)
edge velocity = spin · R_e

Ellipticity — the Hubble class En = 10·(1 − b/a); most ellipticals fall between E0 and E7, and mergers of spiral galaxies are the leading explanation for why the flattening varies so much between them.
Rotation strength — scales the simplified v ∝ r law used in the article: velocity grows linearly with distance from the center, so the whole spheroid turns almost like a rigid body rather than a differentially spinning disk.
Old-star fraction — ellipticals are dominated by old, red Population II stars because mergers strip away the gas and dust that would otherwise fuel new star formation; raising this slider shifts the field from a mixed blue-and-red population toward the uniformly reddish glow real ellipticals show.
Rotation toggle / Auto-orbit — freeze the spheroid's spin to inspect its shape, or let the camera slowly orbit to see the flattening from every angle.

Real-world relevance: elliptical galaxies are thought to represent a late, relatively settled stage of galaxy evolution — the aftermath of mergers that scrambled orbits, quenched star formation, and left behind the smooth light profiles that make ellipticals some of the oldest visible structures in the universe.

Old (Population II) Young / blue Galactic core

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