Pyxis · reference library
General relativity · Newtonian gravity
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Pyxis

Physics, computed.

A reference library of gravity calculators. Pick a phenomenon — time dilation, event horizons, orbital mechanics — and watch the math run on the masses, speeds, and distances that interest you. Built for people who want their physics live, not in a textbook.

Calculators
01
Lorentz Time dilation across special and general relativity. Pick a destination — Mars to Andromeda — choose constant velocity or 1g rocket propulsion, see the twin paradox quantified for any trip you can imagine.
Live
02
Schwarzschild Event horizons, Hawking radiation, tidal forces. From a banana to TON 618 — the radius at which any mass becomes a black hole, plus the cosmic-scale comparator showing where that radius sits in the universe.
Live
03
Kepler Orbital mechanics for two-body systems. Period, velocity, perihelion and aphelion, eccentricity. From the ISS at 400 km to S2's wild swing around Sagittarius A*.
Live
04
Roche Tidal disruption limit. The radius at which a moon, a planet, or a star is pulled apart by the gravity of a larger body. Where Saturn's rings come from, where a star torn by a black hole becomes a tidal disruption event.
Live
05
Hubble Cosmic expansion and redshift — distance relationship. How far away is a galaxy with a given redshift? How fast is space stretching between us and it?
Live
06
Noether Bring your own equations. Symbolic + numerical workbench that evaluates results with units, checks dimensional consistency, and probes how the answer behaves across orders of magnitude. For students, professors, and theorists working out loud.
Live
Roadmap · physicist 07–11
07Cavendish
08Friedmann
09Hawking
10Kerr
11Penrose

Why physicist surnames?

Each calculator is named for the person whose work it computes. Lorentz for the transformations behind time dilation. Schwarzschild for the first exact solution to Einstein's field equations. Kepler for the laws of orbital motion. The point isn't worship — it's traceability. You can read the original papers.

Why a reference library?

Textbooks present gravity statically. These calculators let you play with the numbers — what happens if Earth collapsed to a black hole, how long until a 1g rocket reaches Andromeda, what's the orbital period of a planet around Sagittarius A*. The math is interactive, the physics is canonical, the citations are real.

Pyxis
physics, computed.