What are some interesting facts about Mercury?

Mercury is a battered and baked planet just larger than Earth's moon. Evidence of heavy bombardment from the chaos of the formation of the solar system is left in the hundreds of craters and resulting lava flows on this small, barren planet. The largest crater is Beethoven at 643 km in diameter and is the largest in the solar system. The largest feature, Caloris Basin, is 1300 km in diameter and was probably caused by an impact from an object larger than 100 km in diameter. Some craters have ice in them even though the planet is so hot because the sun never reaches into the shadows due to the planet's tilt and orbit. With no atmosphere, there is a temperature difference of about 600 degrees between the coldest spots and hottest spots on the planet.

Mercury orbits the sun in about 88 Earth days but takes 58 Earth days to rotate once. On this planet a year takes a (Mercury) day and a half!

Interesting Facts About Mercury

1) It is the first planet of the solar system.

2) It is nearest to the sun.

3) It is the smallest planet of the solar system.(after removal of Pluto)

4) It completes its revolution around the sun in 88 earth days.

5) Most of the people think that Mercury is the hottest planet of the solar system but it is not. Venus is the hottest planet of the solar system and Mercury is the second hottest planet.

6) It has no moons.

7) It will merge into sun, when the sun will change to red giant phase.

(edit)

Nabil b has copied his answer from here

http://en.wikipedia.org/wiki/Mercury_(planet)

You can visit the above link for more details with photographs

it's the smallest planet since pluto became a dwarf planet.

it's closest to the sun.

this is all thing concerning mercury

Mercury (pronounced /ˈmɝkjʊəri/) is the innermost and smallest planet in the solar system (since Pluto became a dwarf planet), orbiting the Sun once every 88 days. Mercury is bright when viewed from Earth, ranging from −2.0 to 5.5 in apparent magnitude, but is not easily seen as its greatest angular separation from the Sun (greatest elongation) is only 28.3°: It can only be seen in morning and evening twilight. Comparatively little is known about it; the first of two spacecraft to approach Mercury was Mariner 10 from 1974 to 1975, which mapped only about 45% of the planet’s surface.[5] The second was the MESSENGER spacecraft, which mapped another 30% of the planet during its flyby of January 14, 2008.[5] MESSENGER will make two more passes by Mercury, followed by orbital insertion in 2011, and will survey and map the entire planet.

Physically, Mercury is similar in appearance to the Moon. It is heavily cratered, has no natural satellites and no substantial atmosphere. It has a large iron core, which generates a magnetic field about 1% as strong as that of the Earth.[6] It is an exceptionally dense planet due to the large size of its core. The surface temperatures on Mercury range from about 90 to 700 K (−180 to 430 °C), with the subsolar point being the hottest and the bottoms of craters near the poles being the coldest.

Recorded observations of Mercury date back to the Sumerians in the third millennium BC.[dubious – discuss] Before the 4th century BC, Greek astronomers believed the planet to be two separate objects: one visible only at sunrise, which they called Apollo; the other visible only at sunset, which they called Hermes. The English name for the planet comes from the Romans, who named it after the Roman god Mercury, which they equated with the Greek Hermes. The astronomical symbol for Mercury is a stylized version of Hermes' caduceus.

Contents [hide]

1 Internal structure

2 Surface geology

3 Atmosphere

4 Magnetic field and magnetosphere

5 Orbit and rotation

5.1 Advance of perihelion

5.2 Spin–orbit resonance

6 Observation

7 Studies of Mercury

7.1 Ancient astronomers

7.2 Ground-based telescopic research

7.3 Research with space probes

7.3.1 Mariner 10

7.3.2 MESSENGER

7.3.3 BepiColombo

8 See also

9 Notes and references

10 External links

Internal structure

Mercury is one of the four terrestrial planets that is a rocky body like the Earth. It is the smallest of the four, with a diameter of 4879 km at its equator. Mercury is even smaller—albeit more massive—than the largest natural satellites in the solar system, Ganymede and Titan. Mercury consists of approximately 70% metallic and 30% silicate material. The density of the planet is the second highest in the solar system at 5.43 g/cm³ (water is 1.00 g/cm³), only slightly less than Earth’s density. If the effect of gravitational compression were to be factored out, the materials of which Mercury is made would be denser, with an uncompressed density of 5.3 g/cm³ versus Earth’s 4.4 g/cm³.[7]

1. Crust - 100–200 km thick

2. Mantle - 600 km thick

3. Core - 1,800 km radiusMercury’s density can be used to infer details of its inner structure. While the Earth’s high density results appreciably from gravitational compression, particularly at the core, Mercury is much smaller and its inner regions are not nearly as strongly compressed. Therefore, for it to have such a high density, its core must be large and rich in iron.[8] Geologists estimate that Mercury’s core occupies about 42% of its volume; for Earth this proportion is 17%. Recent research strongly suggests Mercury has a molten core.[9]

Surrounding the core is a 600 km mantle. It is generally thought that early in Mercury’s history, a giant impact with a body several hundred kilometers across stripped the planet of much of its original mantle material, resulting in the relatively thin mantle compared to the sizable core.[10]

Mercury’s crust is believed to be 100–200 km thick. One distinctive feature of Mercury’s surface are numerous narrow ridges, some extending over several hundred kilometers. It is believed that these were formed as Mercury’s core and mantle cooled and contracted at a time when the crust had already solidified.[11]

Mercury has a higher iron content in the core than any other major planet in our solar system, and several theories have been proposed to explain this. The most widely accepted theory is that Mercury originally had a metal-silicate ratio similar to common chondrite meteors, thought to be typical of average solar system rocky matter, and a mass approximately 2.25 times its current mass. However, early in the solar system’s history, Mercury may have been struck by a planetesimal of approximately 1/6 that mass. The impact would have stripped away much of the original crust and mantle, leaving the core behind as a relatively major component.[10] A similar process has been proposed to explain the formation of Earth’s Moon (see giant impact theory).

Alternatively, Mercury may have formed from the solar nebula before the Sun’s energy output had stabilized. The planet would initially have had twice its present mass, but as the protosun contracted, temperatures near Mercury could have been between 2500 and 3500 K (about 4,000 to 5,800 °F), and possibly even as high as 10000 K (about 17,500 °F). Much of Mercury’s surface rock could have been vaporized at such temperatures, forming an atmosphere of "rock vapor" which could have been carried away by the solar wind.[12]

A third theory proposes that the solar nebula caused drag on the particles from which Mercury was accreting, which meant that lighter particles were lost from the accreting material.[13] Each of these theories predicts a different surface composition, and two upcoming space missions MESSENGER and BepiColombo both aim to take observations that will allow the theories to be tested.

Surface geology

First false-color image from MESSENGER.Main article: Geology of Mercury

Mercury’s surface is overall very similar in appearance to that of the Moon, showing extensive mare-like plains and heavy cratering, indicating that it has been geologically inactive for billions of years. Since our knowledge of Mercury's geology has been based on the 1975 Mariner flyby and terrestrial observations, it is the least understood of the terrestrial planets. As data from the recent MESSENGER flyby is processed this knowledge will increase. For example, an unusual crater with radiating troughs has been discovered which scientists are calling a "spider."[14]

Currently known surface features are given the following names in planetary geology:[15]

Albedo features — areas of markedly different reflectivity

Dorsa — ridges (see List of ridges on Mercury)

Montes — mountains (see List of mountains on Mercury)

Planitiae — plains (see List of plains on Mercury)

Rupes — scarps (see List of scarps on Mercury)

Valles — valleys (see List of valleys on Mercury)

Mercury was heavily bombarded by comets and asteroids during and shortly following its formation 4.6 billion years ago, as well as during a possibly separate subsequent episode called the late heavy bombardment that came to an end 3.8 billion years ago. During this period of intense crater formation, the planet received impacts over its entire surface, facilitated by the lack of any atmosphere to slow impactors down. During this time the planet was volcanically active; basins such as the Caloris Basin were filled by magma from within the planet, which produced smooth plains similar to the maria found on the Moon.[16][17]

Mercury’s Caloris Basin is one of the largest impact features in the Solar System.Craters on Mercury range in diameter from a few meters to hundreds of kilometers across. The largest known craters are the enormous Caloris Basin, with a diameter of 1550 km,[18] and the Skinakas Basin with a diameter of 1600 km, but known only from low resolution Earth-based imaging of the non-Mariner-imaged hemisphere. The impact that created the Caloris Basin was so powerful that it caused lava eruptions and left a concentric ring over 2 km tall surrounding the impact crater. At the antipode of the Caloris Basin is a large region of unusual, hilly terrain known as the "Weird Terrain". One hypothesis for the origin of this geomorphological unit is that shock waves generated during the impact traveled around the planet, and when they converged at the basin’s antipode (180 degrees away) the high stresses were capable of fracturing the surface.[19] Alternatively, it has been suggested that this terrain formed as a result of the convergence of ejecta at this basin’s antipode.[citation needed]

The so-called "Weird Terrain" was formed at the point antipodal to the Caloris Basin impact. (Mariner 10 image)The plains of Mercury have two distinct ages: the younger plains are less heavily cratered and probably formed when lava flows buried earlier terrain. One unusual feature of the planet’s surface is the numerous compression folds which crisscross the plains. It is thought that as the planet’s interior cooled, it contracted and its surface began to deform. The folds can be seen on top of other features, such as craters and smoother plains, indicating that they are more recent.[20] Mercury’s surface is also flexed by significant tidal bulges raised by the Sun—the Sun’s tides on Mercury are about 17 times stronger than the Moon’s on Earth.[21]

The mean surface temperature of Mercury is 452 K (179 °C/354 °F),[citation needed] but it ranges from 90 K (−183.1 °C/−297.7 °F) to 700 K (427 °C/800 °F),[citation needed] due to the absence of an atmosphere. The mean noon-time temperature is 620 K (347 °C/656 °F), while the dark-si