Mercury is first and the closest planet to the Sun and It is the smallest planet in our Solar System. Mercury is the second densest planet, the densest planet in Solar System is Earth.
Mercury is very close to the Sun thats why it is hard to directly observe Mecury from Earth except during dawn or twilight.
Like Venus, Earth and Mars it is also known as terrestrial planet. Mercury is the second hottest planet in our Solar System, the hottest planet in Solar Planet is Venus.
Mercury is named for the Roman god of travel because it appears to move so swiftly.
Diameter of Mercury is 4880 km, Rotation Period of Mercury is 59 days, Solar orbit period 88 Days, it has the lowest Solar orbit period in among all planets of Solar System. The Mean distance of Mercury from the Sun is 58 M Km.
Mercury has no natural satellites. The Ganymede, natural satellite of Jupiter and the Titan, natural satellite of Saturn both are larger than Mercury .