Here's why:
* Composition: Mercury is mostly made up of iron and nickel, which are very dense elements. This high metal content gives it a much higher density than planets like Jupiter and Saturn, which are mostly made of gas.
* Small size: While Mercury is the smallest planet in our solar system, its small size means that its gravity is not as strong as that of larger planets. This allows for a higher density of materials to be packed closer together.
So, while Mercury is small, it packs a punch when it comes to density!
