The size of the Earth has not remained constant over millions of years. Geological and geodetic evidence suggests that the Earth has experienced changes in its size and shape throughout its history. These changes occur due to various geological processes and factors such as tectonic activity, volcanic eruptions, erosion, and the redistribution of mass within the Earth.
Over millions of years, tectonic plate movements can cause the Earth's crust to deform, leading to changes in the shape and size of continents and ocean basins. Additionally, volcanic activity can contribute to the formation of new landmasses through processes like volcanic eruptions and the accumulation of volcanic materials.
Furthermore, processes such as erosion and sedimentation can result in the deposition or removal of material from the Earth's surface, leading to changes in its size and shape.
It's worth noting that these changes occur over incredibly long timescales and are relatively small in comparison to the overall size of the Earth. Precise measurements and models based on satellite data and geodetic techniques are used to study and understand these changes in Earth's size and shape.
In conclusion, scientific evidence supports the idea that the Earth has undergone changes in size and shape over millions of years, although these changes are generally minor compared to the overall scale of the planet.