IntroductionIntroduction

The planet Mercury is very difficult to study from the Earth because of its proximity to the Sun. It is the second smallest planet (it was believed to be the smallest until the discovery that Pluto is actually much smaller than originally thought), and also the fastest in its orbit since it is the innermost planet.

Mercury OrbitMercury Orbit

Earth

Mercury, the innermost planet, is 35,983,095 miles from the Sun on the average. It revolves about the Sun once every 88 days in an orbit that is the most elliptical of any planet except Pluto.

Venus

Mercury

Sun

Mercury

Sun

Because of its close proximity to the Sun, Newtonian gravity doesn’t quite work and general relativity is needed to explain some of the aspects of Mercury’s orbit. In fact, this was one of the first tests of general relativity. It was previously thought that the deviations of the motion of Mercury could be solved by assuming planet (named Vulcan) or possibly a second asteroid belt inside Mercury's orbit.

A closer look at MercuryA closer look at Mercury

Mariner 10 oblique view of Wren crater and surroundings on Mercury. Wren crater is barely visible at the lower center of the image, containing a number of craters within its 215 km diameter floor.

Mariner 10Mariner 10

Mariner 10 flew over Mercury at an altitude of 756 km on in March 1974. It took many photographs of the surface of Mercury. Its photographs cover nearly half (the other half is unexplored) the surface area of the planet Mercury.

Mercury StatisticsMercury Statistics

Diameter: 3,030 Miles

Distance from Sun: 35,983,095 miles

Revolution Period about

the Sun: 88 Days

Rotation Period about Axis: 58.85 Earth Days

Number of Moons: None

Information on MercuryInformation on Mercury

MercuryA planet of extremes

Mercury is a lump of rock, barely larger than the Moon, living under the fierce heat of the burning Sun. It experiences extremes in temperature from over 400°C at noon to less than -150°C at night.

Information on MercuryInformation on Mercury

On the surface Mercury is very similar to our Moon, a battered world, scarred by aeons of impacts by meteorites. The surface is also wrinkled, with great ridges hundreds of kilometers long called scarps, which probably appeared when Mercury cooled and shrunk soon after it formed.

The inside of Mercury is more like the Earth. It has a core made of iron, and the centre may be molten, kept hot by radiation deep within the core.

Roman GodRoman God

Mercury originated as the Roman god of commerce and was prayed to mainly by merchants. His name comes from the Latin word "mercari" meaning to deal or trade. Later he came to be associated with the Greek God Hermes, adding responsibility for messages to his duties.

Artists rendition of MercuryArtists rendition of Mercury

From Mercury, the Sun appears two and a half times larger than it does on Earth. The sky would appear black because there's little atmospheric scattering of light. One would be able to see two bright "stars," possibly discernible as cream-colored Venus and blue-colored Earth.

MESSENGER, launched Aug. 3, 2004, is only the second U.S. spacecraft sent to the planet, and it will be the first to establish an orbit. Messenger will enter Mercury orbit on 30th September 2009, and complete its mission one year later.