Mercury's internal composition

Answer 1

Mercury's density and size can be used to infer details of its inner structure. While the Earth's high density results appreciably from gravitational compression, particularly at the core, Mercury is much smaller and its inner regions are not nearly as strongly compressed. Therefore, for it to have such a high density, its core must be large and rich in iron. Geologists estimate that Mercury's core occupies about 42% of its volume; for Earth this proportion is 17%. Recent research strongly suggests Mercury has a molten core.

Surrounding the core is a 600 km mantle. It is generally thought that early in Mercury's history, a giant impact with a body several hundred kilometers across stripped the planet of much of its original mantle material, resulting in the relatively thin mantle compared to the sizable core.

Based on data from the Mariner 10 mission and Earth-based observation, Mercury's crust is believed to be 100-300 km thick. One distinctive feature of Mercury's surface are numerous narrow ridges, some extending over several hundred kilometers. It is believed that these were formed as Mercury's core and mantle cooled and contracted at a time when the crust had already solidified.

Answer 2

Mercury's internal composition is predominantly composed of a large iron-rich core, accounting for about 85% of its volume. Surrounding the core is a silicate mantle, which makes up the remaining 15%. The core is believed to be molten and is responsible for generating Mercury's magnetic field.