IMSN

Expanding Space Gravity – Gravity propagating at light speed

Realistic Gravity Propagation:

• When you toggle the sun’s gravity ON or OFF, the change will propagate outward at the speed of light
• Planets closer to the sun will experience the gravity change sooner than those farther away
• This accurately models how gravitational information travels at a finite speed, not instantaneously

1. Visual Indication of Gravity Propagation:
   • A special wavefront is created when the sun’s gravity is toggled:
     • White wavefront when gravity is turned ON
     • Red wavefront when gravity is turned OFF
   • This wavefront is more visible than regular wavefronts (thicker and more opaque)
   • You can visually track the propagation of the gravity change as it moves outward
2. Physics Implementation:
   • Each object keeps track of the last time the sun’s gravity was toggled
   • The force calculation algorithm now checks if the gravity toggle information has had enough time to reach the object
   • If the information hasn’t arrived yet, the object continues to behave according to the previous gravitational state

How to Observe This Effect:

1. Start the simulation and let the planets establish stable orbits
2. Click the “Toggle Sun’s Gravity” button to turn OFF the sun’s gravity
3. Watch as a red wavefront propagates outward at the speed of light
4. Observe how each planet continues its orbital motion until the wavefront reaches it
5. Once the wavefront passes a planet, it will start moving in a straight line (tangent to its orbit)
6. Toggle the sun’s gravity back ON (creating a white wavefront)
7. Watch as planets resume being attracted to the sun after the wavefront reaches them

This implementation correctly models the physics principle that gravity changes propagate at the speed of light, not instantaneously. It’s a great visualization of how information in space-time travels at a finite speed.