If all land on Earth were merged into one single continent, it would indeed have several significant effects on the rotation of the Earth and its axis. Here are some of the potential consequences:
Redistribution of Mass: The merging of all land into one continent would result in a significant redistribution of mass on the Earth's surface. Currently, the Earth's landmasses are distributed unevenly across the planet. If they were consolidated into one large landmass, the distribution of mass would become more uniform.
Changes in the Earth's Moment of Inertia: The moment of inertia is a property of rotating objects that determines how their mass is distributed around the axis of rotation. When land is distributed across different continents, the Earth's moment of inertia is affected by the varying distances of land masses from the rotational axis. If all land were combined into one continent, the moment of inertia would change, causing alterations in the Earth's rotation.
Shift in the Earth's Axis: The redistribution of mass resulting from merging all land into one continent could cause a shift in the Earth's axis. This shift is known as true polar wander. It occurs when there is a change in the distribution of mass on Earth, leading the rotational axis to adjust to a new position. However, the magnitude and direction of such a shift would depend on the specific configuration of the consolidated landmass.
Changes in the Length of Day: The alteration in the Earth's moment of inertia and the shift in the axis would affect the length of a day. The conservation of angular momentum implies that any changes in the distribution of mass or the axis of rotation would influence the Earth's rotational speed. Consequently, the length of a day, which is defined by one complete rotation of the Earth, would likely be affected.
It is important to note that the above effects are theoretical and complex. The actual consequences of merging all land into one continent would depend on numerous factors, including the precise configuration of the consolidated landmass, its size, shape, and distribution. Modeling and simulating such scenarios would be necessary to obtain more accurate predictions.