Home Plate is a plateau roughly 90 m across within the
Columbia Hills,
Mars
Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...
. It is informally named for its similarity in shape to a
baseball
Baseball is a bat-and-ball games, bat-and-ball sport played between two team sport, teams of nine players each, taking turns batting (baseball), batting and Fielding (baseball), fielding. The game occurs over the course of several Pitch ...
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 (rover), Spirit'' and ''Opportunity (rover), Opportunity'', exploring the planet Mars. It began in 2003 with the launch of the two rove ...
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 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 aphanite, 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 planetary surface, surface of a terrestrial ...
, 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 term chloride refers to a compound or molecule that contains either a chlorine anion (), which is a negatively charged chlorine atom, or a non-charged chlorine atom covalently bonded to the rest of the molecule by a single bond (). The pro ...
s in the surrounding rocks. The presence of
bomb sags (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 silicon dioxide, silica (SiO2ยท''n''H2O); its water content may range from 3% to 21% by weight, but is usually between 6% and 10%. Due to the amorphous (chemical) physical structure, it is classified as a ...
ine
silicon dioxide
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundan ...
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.
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.
See also
*
List of rocks on Mars
Martian rocks and outcrops have been studied ''in-situ'' by various landers and rovers. While many of the rocks identified on the Martian surface are similar to each other, some have been considered scientifically important or otherwise notabl ...
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