Atlas of Worlds

Orrery

Model date · 2026-01-01 · 00:00 UTC

View
Orbits: ecliptic north · Worlds: pole-onBodies enlarged until physical scale

Drag to pan · Pinch to zoom · Shift + arrows to pan

Choose a world to inspect its system.
0–50 AU · linear distances · Bodies enlarged until real scaleApproximate planetary positionsModel / sources
Model / limits / sources

Approximate planetary positions

Model jpl_approximate_orbits_v2. JPL elements and rates cover eight planets, 1800–2050. Kepler's equation and orthographic J2000 ecliptic projection preserve ellipse centers, not the Sun's focus. Outside that interval, shapes freeze at the nearest boundary while mean motion continues schematically.

Earth is the Earth–Moon barycenter. Pluto uses a fixed NASA J2000 ellipse and Atlas's derived orbital period; it is the lowest-fidelity row. Distance readouts are three-dimensional Sun-to-system distances; projected screen separation may be shorter. The four giant planets share proportional mean diameters. Smaller worlds use a compressed size scale for legibility, and the Sun is independently enlarged. Display sizes grow with zoom until physical scale takes over, with orbit clearance limiting enlargement; texture appears as discs become legible. Saturn's face-on rings retain their size relative to its globe.

Approximate Positions of the PlanetsPluto Fact Sheet (2024-02-04 NASA NSSDC archive capture)

Local moon models

Stand on a moon → · Moon model limits

Moon, Europa and Charon use pinned geometric Horizons vectors over 2026 UTC, in the same state model as the surface sky. Outside that window their dated markers are hidden. Straight connectors locate the moons; they are not orbit paths. The diagram is anchored to an approximate parent marker, not an exact heliocentric ephemeris. Earth represents the Earth–Moon barycenter on the global map.

Titan retains illustrative_circular_satellites_v1: a circular orbit at a JPL mean semimajor axis, two-body period, fixed equatorial plane and arbitrary J2000 phase. Its position is illustrative. Dated vectors use physical body centers and an ICRF-to-J2000-ecliptic conversion at the diagram boundary.

Dated model, validation and source requests

  • Moon: Horizons geometric parent/moon centers, 2026 UTC; period is mean-element context
  • Europa: Horizons geometric parent/moon centers, 2026 UTC; period is mean-element context
  • Titan: Titan / 606 / SAT441 / a (km); GM inputs saturntitan
  • Charon: Horizons geometric parent/moon centers, 2026 UTC; period is mean-element context

Globe and ring orientation

World portraits look down the north-side end of each spin axis; the orbital map retains its separate ecliptic-north view. Modelj2000_fixed_poles_v1 chooses the visible hemisphere (negative body latitude for Pluto). Signed sidereal periods drive spin at the shared clock rate, including retrograde rotation. Longitude starts arbitrarily at J2000; surface orientation today is not predicted. Shading is illustrative and rotationally symmetric.

Saturn's pole-on portrait includes the PDS ring boundaries (C-to-A) and Cassini division; moon paths retain their projected equatorial plane. Failed globes retain discs and photographic portraits. The Sun uses its nominal photospheric radius; its disc never shrinks below physical scale.

Sources and resolved values

Dataset 0.1. Method · Complete dataset

JPL Planetary Satellite Mean Elements — semimajor axesPDS Ring-Moon Systems Node — Saturn ring boundariesNAIF PCK 00011 — secular J2000 pole constants