Here's why:
* Seafloor Spreading: Mid-ocean ridges are where new oceanic crust is formed. As magma rises and cools, it becomes magnetized in the direction of Earth's magnetic field at that time.
* Magnetic Reversals: Earth's magnetic field flips periodically, meaning the north and south poles swap places. These reversals are recorded in the newly formed rock as alternating bands of normal and reversed polarity.
* Symmetrical Pattern: As the seafloor spreads, the newly formed crust moves away from the ridge on both sides, carrying the magnetic stripes with it. This creates a symmetrical pattern of stripes on either side, like a mirror image.
This symmetrical pattern of magnetic stripes is a key piece of evidence supporting the theory of plate tectonics and seafloor spreading.
