Orrery

Real Gaia DR3 stars with full 3D positions and velocities, their orbits precomputed, replayed by your GPU. Click any star.
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Development data: Phase 0 sample (46k stars). The 1M-star run replaces these shards with no code change.

Gaia DR3 ...

G magnitude
colour BP-RP
distance from Sun (now)
guiding radius
orbital period
radial swing
vertical swing
vφ − vᶜ(Rℓ)
fit error at 500 Myr
open in the Gaia archive
What is real here, and what is a model
Every point is a real star measured by ESA's Gaia mission (DR3), one of 16,673,098 with full 3D position and velocity passing quality cuts. The motion is a model: each star's orbit was computed as a test particle in a fixed, smooth model of the Galaxy's gravity (MilkyWayPotential2022), then compressed to a short quasi-periodic series evaluated live on your GPU. The real Galaxy has a bar, spiral arms, gas clouds, and stars that pull on each other; this model does not. It is a planetarium-grade reconstruction, not a live or self-gravitating simulation. Ensemble motion is trustworthy; any single star's position half a billion years away is an estimate (median error pc at 500 Myr, and of stars fit worse than 200 pc, marked in their dossier). The stars shown are the bright subset Gaia can fully measure, mostly within a few thousand light-years of the Sun. You are watching the Sun's neighbourhood shear and phase-mix, not tidal streams forming.
t = 0 Myr0.00 galactic years

About Orrery

An orrery of the Milky Way: real stars, their orbits computed on a supercomputer, replayed in your browser across half a billion years.

Developed by

Safeer Ali Mirani

GPU / XR engineer and computational neuroscientist.

safeer.ali.mirani@gmail.com · LinkedIn · github.com/SafeerAliMirani

The data

Every point is a real star from ESA's Gaia mission, Data Release 3 (June 2022). Orrery shows of them, a uniform random sample of the stars with full six-dimensional phase space (3D position and 3D velocity) that pass quality cuts: parallax signal-to-noise ≥ 10, RUWE < 1.4, radial-velocity error < 5 km/s. Distances come from inverted parallaxes; positions and velocities are transformed into a Galactocentric frame (R₀ = 8.122 kpc). This is the bright subset Gaia can fully measure, mostly within a few thousand light-years of the Sun.

The method

Each orbit was integrated ±1 billion years as a test particle in a fixed, smooth model of the Galaxy's gravity (gala's MilkyWayPotential2022) on the CINECA Galileo100 supercomputer, as a 34-task compute array. Each orbit was then compressed to a short quasi-periodic (NAFF-style) series of about a dozen terms — roughly 112 bytes per star — and that series is evaluated live on your GPU every frame. Clicking a star re-evaluates the same series at 512 epochs to draw its orbit ribbon.

Accuracy and honesty

Reconstruction error is a median of parsecs at 500 Myr; of orbits (hot or near-resonant stars) are not well described by a short series and are flagged in their dossier. The model has no bar, spiral arms, gas clouds, or self-gravity, so the motion is planetarium-grade, not a live simulation. Ensemble motion is trustworthy; any single star's deep-time position is an estimate. This shows the Sun's neighbourhood shearing and phase-mixing, not tidal streams forming.

Built with

Raw WebGPU / WGSL, no libraries or frameworks. Orbit integration and fitting in Python (gala, astropy, numpy).

Credits

Gaia data: ESA / Gaia / DPAC, pulled via the Leibniz-Institut (AIP) TAP mirror. Compute: CINECA (project EIRI_E_UNISA2). Gaia DR3 · gala

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