Tidal Forces: Two Bulges & Spring/Neap Tides (2D)

This is the 2D-native counterpart to the 3D tidal-forces simulator. Rather than deforming a rendered sphere, it computes the exact differential gravitational acceleration at every point around Earth's rim — the Moon's pull on that point minus its pull on Earth's center — which is the real definition of a tidal force and is what produces two bulges simultaneously: one from the Moon's stronger near-side pull, one from its weaker far-side pull lagging behind the whole planet's fall toward the Moon. Dragging the Earth-Moon distance slider shows the force fall off as the genuine 1/r³ law, since a tidal force is the difference of two nearby inverse-square pulls. A second slider sets the angle between the Sun and Moon as seen from Earth, blending in the Sun's own (weaker, ~0.46×) tidal pull to show spring tides when the two align and neap tides when they are perpendicular, while a live scrolling tide-gauge trace reads the water height at a fixed point on Earth's crust as it spins through both bulges each day.