Blog note
What an ephemeris actually is, how Keplerian elements and JPL Horizons vectors differ, and how this site turns both into 3D orbit scenes.
Published
What an ephemeris actually is, how Keplerian elements and JPL Horizons vectors differ, and how this site turns both into 3D orbit scenes.
Model policy
When this note discusses simulated movement, scale, spacecraft geometry, or astrophysical structure, the proof is delegated to the relevant mathematical model page or simulator section. The blog does not treat screenshots as theory.
Key Points
Keplerian elements (semi-major axis, eccentricity, inclination, longitudes) describe an orbit's shape and orientation; state vectors give position and velocity at one instant. The site's 3D scenes propagate elements and periodically re-anchor against Horizons vector snapshots.
Elements are quoted at an epoch such as J2000 with secular rates per century. Applying the rates before solving Kepler's equation is what keeps a rendered planet near its true position decades later.
Mean anomaly grows linearly with time, but position needs the eccentric anomaly - found iteratively from M = E - e sin E. Every orbit scene on this site runs that solve each frame.
Where To Continue
Mathematical model
This page does not introduce a standalone generated physics or engineering simulation. Any decorative background or static illustration is presentation only; mathematical claims must come from the cited equations, catalog values, or linked model-verification pages.
Decorative images, icons, and background effects on this page are not used as evidence for a scientific or engineering statement.
If the text gives a quantitative fact, it must be traceable to a data field, unit conversion, or equation on the relevant detailed page.
Interactive pages linked from here carry their own mathematical model sections with equations, assumptions, proof notes, and limitations.
Verification standard: the rendered object must be reproducible from stated equations, catalog parameters, or explicit geometric transforms. Visual reference images may inform presentation only; they are not the source of orbital positions, field vectors, accretion-disk gradients, timing, or engineering layout.
Limitations: browser scenes may use bounded scale, compressed distances, simplified two-body dynamics, schematic transfer curves, or educational approximations where full numerical ephemerides, CFD, finite-element models, or general-relativistic ray tracing are outside the page scope. Those simplifications are part of the model contract, not hidden image-based construction.