You're raising an excellent point about how gravity and tidal forces do influence planetary shapes and orientations over long timescales! This line of reasoning is crucial for understanding why Uranus is such an outlier. Let's break down your observation about Earth's equatorial bulge and apply it to Uranus: Earth's Equatorial Bulge and Tidal Evolution: You're absolutely right that Earth bulges at its equator. This is due to a combination of two factors: * Rotation: As Earth spins, the material at the equator is flung outward by centrifugal force, causing it to bulge. * Gravity: Earth's own gravity pulls everything towards its center, but it's not strong enough to completely overcome the centrifugal force at the equator. Now, regarding "parallel over time" and tidal effects: * Tidal Forces: The gravitational pull of other celestial bodies (like the Sun and Jupiter, but primarily the Sun for Uranus's orbital plane) exerts tidal forces on a planet. These forces try to pull a planet into alignment with the gravitational field. * Tidal Locking/Alignment: Over incredibly long periods, tidal forces can indeed cause a planet's axis of rotation to precess (wobble) and, in some cases, align with its orbital plane or even become tidally locked (where one side always faces the orbiting body, like the Moon with Earth). This process is dependent on the planet's internal structure, its distance from the gravitational source, and its initial rotation. Why Uranus Remains Tilted (and its Rings with it): This is where the unique circumstances of Uranus, and the sheer magnitude of the proposed impact, become critical. * Initial Impact Energy: The hypothesized giant impact would have imparted an enormous amount of angular momentum to Uranus, fundamentally changing its rotational axis. We're talking about an energy scale far beyond the subtle, long-term effects of tidal forces that cause equatorial bulges or gradual axial alignment. * Conservation of Angular Momentum: Once a planet has a certain amount of angular momentum and is spinning on a particular axis, it takes a very significant external force to change that. While tidal forces do exert a torque, for a massive planet like Uranus, this torque is relatively weak compared to the angular momentum imparted by the initial collision. * Lack of Strong External Torque: * Sun's Gravity: While the Sun exerts tidal forces on Uranus, Uranus is much farther away from the Sun than Earth is. Tidal forces weaken rapidly with distance (inversely proportional to the cube of the distance). So, the Sun's ability to "right" Uranus is significantly diminished compared to its influence on inner planets. * Other Planets: While Jupiter and Saturn are massive, their gravitational influence on Uranus's axial tilt is also relatively weak due to distance. * Time Scale: The time required for tidal forces to significantly alter the axial tilt of a large, distant planet like Uranus would be incredibly long – far longer than the age of the solar system. While precession (a wobble of the axis) does occur due to solar and planetary gravity, it doesn't fundamentally change the tilt itself over such timescales for a planet of Uranus's mass and distance. * Rings and Moons as a "System": Crucially, the entire system – Uranus, its rings, and its regular moons – is all tilted together. This strongly implies that the tilt of the planet is the primary cause, and the rings and moons simply formed or re-aligned with that tilted equatorial plane. If tidal forces were slowly trying to pull Uranus upright, they would also be affecting the rings and moons in a similar fashion. The fact that the entire system remains coherent in its tilt is powerful evidence against a slow, gradual alignment. Conclusion: You're correct that gravity, through tidal forces, does work to align planetary systems over vast timescales. However, the initial energy of the hypothesized giant impact on Uranus was so immense that it set up a configuration that the relatively weaker, long-term tidal forces from the distant Sun simply haven't been able to "correct" within the age of the solar system. The conservation of angular momentum means that once Uranus was tipped, it largely stayed that way, with its rings and moons following suit.