All about Mercury | Physical characteristics | Orbit and Rotation | Mercury missions

As most of us know our Earth is part of a superordinate planetary system. In detail this consists of eight different planets which orbit around a fixed star our sun at a finely tuned regularity. The corresponding celestial bodies however are as diverse as they are astonishing. 

Saturn amazes people with its gigantic ring system and its countless moons. Mars also known as the red planet has always been accompanied by fantastic myths and legends.


For comparison the Earth is located on average about 149.6 million kilometers away from our central fixed star. This small distance also ensures that Mercury is the fastest celestial body in our planetary system. While our blue home planet is known to take 365 days to completely orbit the sun. Mercury manages this feat in just 88 days.

Mercury is not only the fastest, closest and smallest of planets in our solar system. With a diameter of 142870 kilometers Jupiter represents the upper end of the flagpole, at the same time Mercury diameter in kilometres is 4880. In the case of our earth the corresponding value is 12742 kilometers.

Mercury composition

Mercury consists of approximately 70% metallic and 30% silicate materials. It’s actually more metallic than rocky. Because of this, Mercury’s density is the second highest in the solar system at 5.427 grams per centimetre cubed. Only slightly less than the planet with the greatest density – that of Earth at 5.515 grams per centimetre cubed.

If Mercury happened to be the same size as Earth, that would mean it would have pretty the same gravitational pull as its surface. But being the size that it is, its surfacegravity is only 3.7 metres per second squared.

Orbit and Rotation

Mercury has the most eccentric orbits of all the planets. With its distance from the Sun ranging from 46 million kilometres to 70 million kilometres. Mercury takes about 88 Earth days to completean orbit around the Sun. It also has a 3-2 spin orbit resonance of the planet’s rotation around its axis.

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