Stats

Density: 5.427g/cm³

Volume: 0.054 earths, or 6.083×1010 km³

Mass: 0.055 earths, or 3.3022×1023 kg

Satellites: None

Axial tilt: 0.01°

Atmosphere composition: 31.7% Potassium, 24.9% Sodium, 9.5% Atomic Oxygen, 7.0% Argon, 5.9% Helium, 5.6% Oxygen, 5.2% Nitrogen, 3.6% Carbon dioxide, 3.4% Water, 3.2% Hydrogen

Mercury is the eighth largest planet in our solar system. It is also the closest planet to thesun, ranging at 57,909,175 km (Average). Mercury is named after Hermes, the god ofmessenger, because Mercury travels the fastest out of all the planets in the sky, orbitingthe Sun in 88 days. Observations of Mercury have been recorded since the time of theSumerians, around 3000 B.C. The first telescopic observations, however, was made byGalileo in early 17th century.  Very little is actually known of Mercury, as the only spacecraftthat approached Mercury was Mariner 10, which mapped around 45% of Mercury. Mercury isalso closer to the sun, than it is to Earth, and also because of the angular separation, 28.3degrees, it is almost impossible to see Mercury on earth. It can only be seen in themorning, and at evening twilight. The temperature on Mercury is very extreme, ranging from180 to 430 °C. −

Mercury is very similar to the Moon in terms of physical shape. It is covered with craters, has no satellites, or a standard atmosphere. Mercury consists of a huge iron core, taking up42% of its total volume, and also generates a magnetic field. The iron core’s radius isaround 1800 km to 1900 km. However, this magnetic field is only 1% of that of the earth. Mercury is made up of 70% metallic materials, and 30% silicate materials. However, because of the iron core, Mercury’s density is the second highest in the solar system, at5.43g/km³. Mercury, as mentioned above, has tons of craters. This is resulting from theheavily bombardment of comets and asteroids billions of years ago. Also, because of thelack of atmosphere, nothing stopped the asteroids from smashing into Mercury. Theatmosphere that surrounds Mercury is almost non-existent. The atmosphere contains tracesof hydrogen, helium, oxygen, sodium, calcium, and potassium. The reason why Mercurycannot sustain an atmosphere is because of its size. It is simply too small, and generatestoo less of a gravity to sustain it.

The orbit of Mercury is very interesting. Even though it takes only 88 days to orbit the Sun, the planet distance can vary from 46,000,000 to 70,000,000 kilometers. Also, Mercurytravels around the sun in a non-circular orbit, rotating 3 times for every 2 revolutionsaround the sun. It takes around 59 days to rotate once around its axis. This is called a 3:2spin-orbit resonance. Usually, a planet’s resonance is only 1:1. Simulations shows that thecraziness of Mercury’s orbit is due to the fact that the orbit varies from 0 (circular motion) to 0.47 over millions of years. The axis tilt of Mercury is at 0.01 degrees, which is 300times smaller to that of Jupiter.