In the bowels of Mercury contains a large number of metals, which form its core. Density of Mercury in grams per cubic centimeter: 5.427 g/cm 3 Axis of Mercury Like all of the planets in the Solar System, the axis of Mercury … This planet has mass of 0.06 × Earth mass. Mercury Physical properties. Observations of Mercury. Mercury, the innermost planet of the solar system and the eighth in size and mass. Scientists have discovered that Mercury has the highest density of all the known planets (other than Earth). Length of day on mercury is 58 Earth days. No other planet, moon, or even asteroid comes close. The core is about 80% of Mercury. Compared to earth mercury is closer to the sun with the average distance of 5.78 billions kilometre. A planet's density tells astronomers important things about its inner structure.For example, Mercury is almost as dense as Earth, even though it's much smaller. Because its rising or setting is always within about two hours of the Sun’s, it is never observable when the sky is fully dark. The density of craters on the surface of a planet can be used to indicate the relative age of different places on the surface; the more craters the surface has accumulated, the older the surface. It has two physical properties of special interest. The density of mercury is 13.59 grams per cubic centimetre. [+] Earth is the densest planet of all in the Solar System: about 2% denser than Mercury and about 5% denser than Venus. https://nssdc.gsfc.nasa.gov/planetary/factsheet/mercuryfact.html Despite its small size, Mercury is very dense because it is composed mainly of heavy metals and rock – the main characteristic of terrestrial planets . The planet is known as Mercury - this isthe name of the Roman god-messenger. Mercury metal can be frozen changed into a solid at a temperature of –38.85°C. Its closeness to the Sun and its smallness make it the most elusive of the planets visible to the unaided eye . The average radius of the planet Mercury is 2439.7 km. It is the second planet in density, after the Earth. Mercury is so dense that it’s thought to have an iron core occupying some 75% of its diameter.1 This extraordinary density has generated much turmoil and confusion in evolutionary astronomy. It can be transformed into a gas when boiled at 365.6°C. Mercury is the smallest planet in the solar system with a diameter of 4,879 km and is one of five planets that is visible to the naked eye. Like the other three terrestrial planet, Mercury contains a core surrounded by a mantle and a crust. It’s density is 0.05 time the earth density, thus mercury is less dence than the earth. After the Earth, Mercury is the second densest planet. The smallest planet in the solar system, Mercury bears a strong resemblance to Earth's moon. Since a small planet experiences less gravitational compression than a larger planet—that is, the effects of gravity don't squish it down as much—astronomers need to look for another reason for its density. Length of year on mercury is 88 Earth days Mercury element in the periodic table is symbolized as Hg.