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Information on Mercury

Mercury is the first and most inner planet to the sun. Mercury is the second smallest planet in the solar system, just a little bigger than the Earth’s moon. Mercury surface is covered in craters just like Earth moon. The structure of Mercury is believed to have a metallic core, an intermediate rocky layer and a thin crust. Mercury is probably high in iron this is thought because the surface feature indicates that there was once volcanic activity on the surface.In Mercury’s early days the surface would have been very active.

Structure of Mercury: Mercury has a radius of 2439 km across, the core of metallic iron make up about 75% of this distance. The planet indicates that the core is likely to be hot and fluid, this may be because it is so close to the sun.

Atmosphere: When a spacecraft when over Mercury it detected a tiny amount of helium 1000 km above the surface of the planet. This was achieved by capturing particles from solar winds and radioactive decay of the crust. The pressure on Mercury is one million billionths that of Earths, the outer atmosphere includes other elements like sodium, potassium and oxygen but all these gases are ionised by solar radiation. The temperature on the surface of Mercury can range between –300 and 800 of (this is hot enough to melt lead). The large temperature range is probably because Mercury is so close to the sun. Mercury has 88 days in a year, which is far less than earths.

Discover Mercury: Mercury is difficult to see because it is so close to the sun, and is very difficult to see from the ground. This is why when early astronomers were looking at the planet they couldn’t see Mercury. Mercury can only be seen at twilight because it is masked by the glare from the sun.The record ever made of Mercury was by Timocharis in 265BC. Zupus studied the orbit of the sun in 1639 and Schorster and Harding studied the very faint surface in 1800. Mercury was difficult to see the surface from Earth, it wasn’t until 1960’s that scientist determined the correct rotation rate of the planet on its axis to 59 Earth days.

Diameter:	Mass:	Density:	Minimum Distance From Sun:	Maximum Distance from Sun:	Orbital Semimajor Axiz:	Minmum Distance from Earth:
4,878 km (3,030 miles)	0.33x10^24 kilograms (0.06 x Earth's)	5,427 kg/m^3	46.0 million km (28.6 million miles)	69.8 million km (43.4 million miles)	0.387 AU (Earth=1 AU)	77.3 million km (48.0 million miles)
Rotation Period about Axis:	Revolution Period about the Sun:	Tilt of Axis:	Surface Gravity:	Temperature Range on Mercury:	Averager Surface Temperature (K):	Satellties:
58.65 days	0.24 years	0 o	3.7 m/s^2 (0.38 x Earth's)	-184o C to 427o C (-300o F to 800o F)	440K	0