Despite being only slightly larger than Earth's moon, Mercury is extraordinarily dense. It boasts a disproportionately large, ...

Mercury ' s inner core is solid and about the same size as Earth ' s inner core, a new study using observations from NASA's MESSENGER mission has indicated. Mercury is the smallest planet in our ...

Mercury, Venus, Earth and Mars, were created closest to the Sun. Made of rocks and metals, they have solid surfaces and a central core of mainly iron. Small in comparison to the gas planets found ...