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Gravity Sim screenshots   ( Netlogo environment )

(1) Demonstration of orbiting gyroscope dynamics.
This also shows the distinction between an ‘inertial’ orbit and an orbit with synchronous rotation.*

* (The rotation of an orbiting body on its axis in the same amount of time as it takes to complete a full orbit, with the result that the same face is always turned toward the body it is orbiting.) Dynamical behavior of a gyroscope in an orbiting reference frame with synchronous rotation.

(2)  Set up Simulation   for Radial free fall simulation.

Gravity Sim gravity-simulation software

Schematic of default radial free fall simulation
highlighting the nature of lateral tidal forces.

Radial free fall schematic

(3) Default Radial free fall simulation (in progress).

Free fall simulation: gravitational tidal forces produce the 'spaghetti effect.'

All Gravity Sim simulations are produced in a very simple way using the Euler method. Because the simulated reference-frame orbit is an idealized perfect circle (e = 0), intrinsic local error (error per step) is known, so the resulting minute position error of the reference-frame centroid can be corrected after each step. Consequently, the global error (error at a given time) in the position of the reference frame is always zero, which implies that the calculated accelerations on the test masses are equally accurate throughout a simulation.

Because of the foregoing methodology, the simulated dynamical behavior of the test masses over time (right frame) is extremely accurate. Gravity Sim employs double-precision (64-bit) floating point numbers as defined in the IEEE 754 standard (binary64), which allows for approximately 16 decimal digits of calculation precision.

If it is not legible on your screen, the message in orange at the bottom of the right frame (4, 5, 6) states: “Interaction is exclusively with the mass of the Earth and the orange ball [at the reference-frame centroid]; no interactions occur between the eight 1-gram test masses.”

(4) Default Circular orbit simulation (in progress).

Simulation of gravitational tidal effects.

(5) Dynamical results of Circular orbit simulation after 1.4 orbital revolutions compared to morphology of a “grand spiral” galaxy (M51).

The trace dots recording dynamical behavior are equally spaced in time; the particles accelerate as they naturally migrate outward, which is also seen in the v(R) graph.

gravity simulation producing spiral galaxy morphology

(6) Match the image simulation (in progress).

Simulation of spiral galaxy formation.

(7) Empty space simulation (in progress) — the identical simulation code for all simulations producing Keplerian elliptical orbits.

Gravity simulation: Keplerian elliptical orbits.

(8) Splash screen of commemorative Lunar Reconnaissance Orbiter (LRO) ephemeris, also showing landing sites of Apollo missions.

Apollo Landing Sites & Lunar Reconnaissance Orbiter (LRO).

To run Gravity Sim now, see the homepage links (top right).