☉Solar System Simulator

Experimental school / two runs, one question

One question. Two experiments.

Make a prediction, run a ready-made experiment, and compare what happened. Both runs start from the same physical state.

Open the 3D simulator · Read the experiment guide

Loading the C comparison module…

Choose a question

Does a smaller timestep improve an orbit?

Run A calculates motion every 300 seconds; run B every 150 seconds. Which will stay closer to an ideal circular orbit?

Write a prediction (optional)

Settings are ready. Start the comparison, then look at analytical phase error and energy change.

Adjust experiment settings

Change one variable at a time. A smaller timestep means more calculations; it does not change how quickly plot time passes.

Run A

Run B

Sample spacing must be a whole number of each run's ticks; duration must contain whole samples. The core uses 15-second Verlet; core and barycentric-core preserve initial speed factor 1. The head-on sphere lesson requires bounce/merge and 0.01–0.25-second steps. Its masses, radii and speeds are chosen classroom parameters.

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Last matched time: — · Tracked subject: —

Run configuration and provenance

C runtime revision: —

Displayed results use: no run started

At most 1,025 chart points; history spacing coarsens uniformly. Native CLI exports every requested checkpoint.

A — solid blue · B — dashed copper. Runs compute as fast as bounded batches permit; horizontal plot time is simulated seconds.

Overlaid trajectories

Run a comparison to read axis values.

Physical X/Z projection

Energy change

Run a comparison to read axis values.

ΔE / (K₀ + |U₀|); includes modeled contact losses

Orbital distance

Run a comparison to read axis values.

Meters from parent, or inertial origin for parentless subjects

Speed

Run a comparison to read axis values.

m/s relative to parent, otherwise inertial

Analytical phase error

Run a comparison to read axis values.

Angular separation in degrees, 0–180; isolated two-body lessons only

A/B position discrepancy

Run a comparison to read axis values.

Meters; discrepancy is not an independent accuracy reference

Resonant angle

Run a comparison to read axis values.

3λ Jupiter − 2λ particle − ϖ particle, wrapped to ±180°
Accessible numeric measurements

Unavailable analytical references and merged-away subjects are explicit. Merging changes mechanical energy; a zero- or small-error total does not prove accurate phase.

SI measurementRun ARun B

Force-contribution inspector

Top six sources at the matched checkpoint. Each percentage divides the source's acceleration magnitude by the sum of all source magnitudes. Vectors can cancel, so these are not percentages of net acceleration. Unknown-mass tracers feel gravity but contribute none. Fixed bodies may have computed gravity while their positions remain constrained.

Run A — acceleration contributions
Sourcem/s²Magnitude shareX, Y, Z (m/s²)
Run B — acceleration contributions
Sourcem/s²Magnitude shareX, Y, Z (m/s²)

Interpret the model.

  • Barycentric core: all masses move, including the Sun; initial relative states are preserved by a mass-weighted translation and velocity shift.
  • Resonance: a 3:2 initial period ratio is a starting hypothesis. Inspect the resonant angle over long runs for libration versus circulation; angle-wrap gaps are not physical jumps.
  • Close encounter: reduce the timestep and compare the minimum integrated parent distance and deflection. This is a fixed-step accuracy study, not adaptive integration.
  • Collisions: a deliberately head-on two-sphere model. Bounce conserves contact kinetic energy and momentum; merge conserves mass and linear momentum and loses kinetic energy. Internal spin and general collision detection are outside this lesson.