All eight planets rendered on a single heliocentric chart. Orbital radii are log-spaced so Mercury and Neptune are both readable in one view — true-scale would push the inner planets into the Sun.

Each planet's angular position (mean longitude) is computed live from the J2000 epoch using its sidereal orbital period. Distance tags update every 5 minutes from NASA JPL Horizons.

True anomaly in degrees is the live angle of each planet within its current orbit, measured from its most recent perihelion (0°). At 180° it reaches aphelion; at 360° it returns to perihelion and the cycle resets. This is the same angle astronomers use.

Why apsides? Perihelion and aphelion form a core cycle — an orbit defined purely by a body and the single mass it orbits, with no dependence on any third body. This gives the cleanest, most fundamental rhythm to study. By contrast, something like the Moon's phase is a compound cycle: it depends on the constantly-shifting geometry of Sun, Earth and Moon together.

We also show % of orbit complete (0–100% per cycle) and angular frequency ω in radians per second — the constant rotational speed that defines the planet's "frequency" of orbit.

The Σ Sum and μ Average at the bottom form a unique 8-planet alignment signature that effectively never repeats — a fingerprint of this exact moment in solar-system history.

The chronological "Upcoming Apsides" feed is dominated by inner planets that complete an orbit in months. This panel guarantees the next perihelion and aphelion for every one of the eight planets, even when the outer giants don't reach their next extreme for decades (Uranus aphelion ≈ 2092).

Data is pulled from our verified ephemeris database (1900–2100, cross-checked annually against AstroPixels).

Closest (perihelion) and farthest (aphelion) approach of each planet to the Sun. Computed from VSOP87-derived Keplerian elements with secular variations (Standish 1992, Meeus Ch. 31) for the years 1900–2100.

Distances are in astronomical units (1 AU = 149,597,871 km). Inner planets cycle through apsides quickly (Mercury every ~88 days), while outer planets reach them on geological timescales (Neptune every ~165 years).

Ceres orbits in ~4.6 years, but the trans-Neptunian dwarf planets (Pluto, Haumea, Makemake, Eris) have orbital periods between 248 and 558 years — their next apsis can be decades or centuries away. That is correct, not missing data.

Distances are computed from osculating Keplerian elements at J2000 (JPL Small-Body Database). Trans-Neptunian times are accurate to days; Ceres to hours.