Gvozdeno jezgro unutar Merkura čini oko 40% zapremine planete, dok na Zemlji, na primer, jezgro iznosi samo oko 20% ukupne zapremine, iako je Zemlja oko tri puta veća od Merkura.
The iron core inside Mercury is about 40% of the volume of the planet. Whereas on Earth, for example, the core is only about 20% of the Earth's total volume, even though Earth is about three times larger than Mercury.