Home Plate is a plateau roughly 90 m across within the Columbia Hills,

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...

. It is informally named for its similarity in shape to a

baseball Baseball is a bat-and-ball sport played between two teams of nine players each, taking turns batting and fielding. The game occurs over the course of several plays, with each play generally beginning when a player on the fielding t ...

home plate A baseball field, also called a ball field or baseball diamond, is the field upon which the game of baseball is played. The term can also be used as a metonym for a baseball park. The term sandlot is sometimes used, although this usually refers ...

. Home Plate is a rocky outcrop that appears to show layered features. The plateau has been extensively studied by ''Spirit'', one of the

Mars Exploration Rover NASA's Mars Exploration Rover (MER) mission was a robotic space mission involving two Mars rovers, '' Spirit'' and '' Opportunity'', exploring the planet Mars. It began in 2003 with the launch of the two rovers to explore the Martian surface ...

s, since 2006. The rover became stuck in loose granular material alongside the northeast side of the plateau. The rover last communicated with Earth on March 22, 2010.

Exploration

''Spirit'' arrived at Home Plate on

sol Sol or SOL may refer to: Astronomy * The Sun Currency * SOL Project, a currency project in France * French sol, or sou * Argentine sol * Bolivian sol, the currency of Bolivia from 1827 to 1864 * Peruvian sol, introduced in 1991 * Peruvian sol ...

744 (February 7, 2006) and has completed a scientific investigation with her robotic arm before moving to Low Ridge Haven due to power concerns. She returned on sol 1126 to resume those studies. ''Spirit'' spent her third Martian winter on Home Plate's north edge.

Origins

Scientists now believe that Home Plate is an explosive volcanic deposit. It is surrounded by deposits of

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

, which are believed to have exploded on contact with water. The presence of brine is further supported by the high concentration of

chloride ion The chloride ion is the anion (negatively charged ion) Cl−. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride salt ...

s in the surrounding rocks. The presence of

bomb sag Sedimentary structures include all kinds of features in sediments and sedimentary rocks, formed at the time of deposition. Sediments and sedimentary rocks are characterized by bedding, which occurs when layers of sediment, with different partic ...

s (laminae typically found in beds of volcanish ash) seems to confirm this hypothesis. A patch of 90% pure

opal Opal is a hydrated amorphous form of silica (SiO2·''n''H2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Due to its amorphous property, it is classified as a mineraloid, unlike crystalline form ...

ine

silicon dioxide Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...

was unearthed by ''Spirit'' in the vicinity of Home Plate. The patch is believed to be formed in acidic hydrothermal conditions, which supports the theory that Home Plate is of an explosive volcanic origin. Water is also present as mineral

hydrate In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understo ...

s. Since 2008, scientists believe that this formation is an example of an eroded, ancient, and extinct

fumarole A fumarole (or fumerole) is a vent in the surface of the Earth or other rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcani ...

.The Hydrothermal System at Home Plate in Gusev Crater, Mars, R.V.Morris, S.W.Squyres, -et al., Lunar & Planetary Science XXXIX(2008)

Gallery

File:Home plate.JPG, ''Spirit'' imager moves towards Home Plate. File:Bomb sag on Mars.jpg, Bomb sag File:Home plate anim.gif, Curious rock, "animated" via wiggle stereoscopy.

References

External links

Nasa's Mars Exploration Program
- Home Plate is visible, with ''Spirit''s journey around it.
The Planetary Society Weblog: Home, Sweet Home for ''Spirit''

Official Mars Rovers site
{{Portal bar, Solar System Rocks on Mars Fumaroles Mars Exploration Rover mission

Exploration

Origins

Gallery

See also

References

External links