How might a giant collision have helped create Mercury’s large core?

Some planetary scientists hypothesize that during Mercury’s early history, after the planet had already differentiated into a dense iron-rich core and a lighter silicate mantle and crust, a giant collision occurred. This impact is thought to have stripped away much of the planet's outer silicate layers, leaving behind a body dominated by its massive core.1

This proposed event is considered similar to the collision of a Mars-sized object with Earth, which is widely believed to have formed the Moon. By removing the outer rocky shell, such a collision would explain why Mercury possesses an unusually large iron core, which accounts for nearly two-thirds of the planet's mass and extends to about 85 percent of the way to its surface.12

However, this remains one of several competing theories, as other processes—such as the preferential vaporization of silicates due to the heat of the early Sun or aerodynamic sorting in the solar nebula—may also account for the planet's high density.1