It has been suggested that Gillevinia straata be merged into this article or section. (Discuss)

An electron microscope reveals bacteria-like structures in meteorite fragment ALH84001

Scientists have long speculated about the possibility of life on Mars owing to the planet's proximity and similarity to Earth. It remains an open question whether life exists on Mars now, or existed there in the past. Life on Mars can refer to: Life on Mars, the possibility of life on the planet Mars Martians, fictional intelligent inhabitants of Mars Life on Mars?, the David Bowie song from the album Hunky Dory Life on Mars (TV series), a British television drama series that takes its title from... Image File history File links Mergefrom. ... It has been suggested that this article or section be merged with Life on Mars. ... Structures on ALH84001 meteorite Photo credit: NASA File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Structures on ALH84001 meteorite Photo credit: NASA File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Meteorite fragment ALH84001 ALH 84001 (Allan Hills 84001) is a meteorite found in Allan Hills, Antarctica in December 1984 by a team of US meteorite hunters from the ANSMET project. ... This article is about Earth as a planet. ... Adjectives: Martian Atmosphere Surface pressure: 0. ...

Early speculation

Mars' polar ice caps were observed as early as the mid-17th century, and they were first proven to grow and shrink alternately, in the summer and winter of each hemisphere, by William Herschel in the latter part of the 18th century. By the mid-19th century, astronomers knew that Mars had certain other similarities to Earth, for example that the length of a day on Mars was almost the same as a day on Earth. They also knew that its axial tilt was similar to Earth's, which meant it experienced seasons just as Earth does - but of nearly double the length owing to its much longer year. These observations led to the increase in speculation that the darker albedo features were water, and brighter ones were land. It was therefore natural to suppose that Mars may be inhabited by some form of life. False colour view of a landslide in Zunil crater The geology of Mars, also known as areology (from Greek: Ἂρης, Arēs, Ares; and λόγος, logos, knowledge), refers to the study of the composition, structure, physical properties, history and the processes that shape the planet Mars. ... For other persons named William Herschel, see William Herschel (disambiguation). ... Adjectives: Martian Atmosphere Surface pressure: 0. ... Various schemes have been used or proposed to keep track of time and date on the planet Mars independently of Earth time and calendars. ... In astronomy, axial tilt is the inclination angle of a planets rotational axis in relation to a perpendicular to its orbital plane. ... The Darian Calendar is a system of time-keeping designed to serve the needs of any possible future human settlers on the planet Mars. ... An albedo feature is a large area on the surface of a planet (or other solar system body) which shows a contrast in brightness or darkness (albedo) with adjacent areas. ...

In 1854, Phillip loiterton, a fellow of Trinity College, Cambridge, who popularized the word scientist, theorized that Mars had seas, land and possibly life forms. Speculation about life on Mars exploded in the late 19th century, following telescopic observation by some observers of apparent canals — which were however soon found to be optical illusions. Despite this, in 1895, American astronomer Percival Lowell published his book Mars, followed by Mars and its Canals in 1906, proposing that the canals were the work of a long-gone civilization. This idea led British writer H. G. Wells to write The War of the Worlds in 1897, telling of an invasion by aliens from Mars who were fleeing the planet’s desiccation. Full name The College of the Holy and Undivided Trinity Motto Virtus vera nobilitas Virtue is true Nobility Named after The Holy Trinity Previous names King’s Hall and Michaelhouse (until merged in 1546) Established 1546 Sister College(s) Christ Church Master The Lord Rees of Ludlow Location Trinity Street... The University of Cambridge (often Cambridge University), located in Cambridge, England, is the second-oldest university in the English-speaking world and has a reputation as one of the most prestigious universities in the world. ... For a time in the late 19th and early 20th centuries, it was believed that there were canals on Mars. ... Year 1895 (MDCCCXCV) was a common year starting on Tuesday (link will display full calendar) of the Gregorian calendar (or a common year starting on Sunday of the 12-day-slower Julian calendar). ... Percival Lowell (March 13, 1855 – November 12, 1916) was an author, mathematician, and esteemed astronomer who fueled speculation that there were canals on Mars, founded the Lowell Observatory in Flagstaff, Arizona, and formed the beginning of the work and theories that led to the discovery of Pluto 14 years after... 1906 (MCMVI) was a common year starting on Monday (see link for calendar). ... Herbert George Wells (September 21, 1866 – August 13, 1946), better known as H. G. Wells, was an English writer best known for such science fiction novels as The Time Machine, The War of the Worlds, The Invisible Man, The First Men in the Moon and The Island of Doctor Moreau. ... The War of the Worlds (1898), by H. G. Wells, is an early science fiction novel (or novella) which describes an invasion of England by aliens from Mars. ...

Spectroscopic analysis of Mars' atmosphere began in earnest in 1894, when U.S. astronomer William Wallace Campbell showed that neither water nor oxygen were present in the Martian atmosphere.^[1] By 1909 better telescopes and the best perihelic opposition of Mars since 1877 conclusively put an end to the canal theory. William Wallace Campbell (April 11, 1862 – June 14, 1938) was an American astronomer. ...

Mariner 4

The photographs taken by the Mariner 4 probe in 1965 showed an arid Mars without rivers, oceans or any signs of life. Further it revealed that the surface (at least the parts that it photographed) was covered in craters, indicating a lack of plate tectonics and weathering of any kind for the last 4 billion years. The probe also found that Mars had no magnetic field that would protect the planet from potentially life-threatening cosmic rays. The probe was also able to calculate the atmospheric pressure on the planet to be between 4 and 7 millibars, meaning that liquid water could not exist on the planet's surface.^[1] After Mariner 4, the search for life on Mars changed to a search for bacteria-like living organisms rather than for multicellular organisms, as the environment was clearly too harsh for these. Mariner 4 (Mariner-Mars 1964) was the fourth in a series of spacecraft used for planetary exploration in a flyby mode and performed the first successful flyby of the planet Mars, returning the first pictures of the Martian surface. ... Year 1965 (MCMLXV) was a common year starting on Friday (link will display full calendar) of the 1965 Gregorian calendar. ... Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. ...

Viking experiments

Main article: Viking biological experiments

The primary mission of the Viking probes of the mid-1970s was to carry out experiments designed to detect microorganisms in Martian soil. The big difficulty of this mission was that NASA's knowledge about conditions on Mars' surface was limited to the data returned by Mariner 4, and so the tests were formulated to look for life similar to the life found on Earth. Nevertheless, of the four experiments carried out, the labeled release experiment returned an enigmatic result showing increased CO₂ production on first exposure to water and nutrients. However this sign of life was disputed by many scientists, who argued that superoxidant chemicals in the soil could have produced this effect without life being present. To counter this it has been argued that the labeled release experiment detected that there were so few metabolising organisms in the martian soil that it would have been impossible for the gas chromatograph to detect them. This view is put forward by one of the designers of the LR experiment, Gilbert Levin, who believes the results of the Viking landers are diagnostic for life on Mars^[1]. The two Viking spacecraft each carried four biological experiments to the surface of Mars in the late 1970s. ... Viking mission profile. ... There are very few or no other articles that link to this one. ... –Gilbert Levin is an American engineer, the founder of Spherix and famous for experiments on Mars soil and the development of tagatose. ...

A re-analysis of the now 30 year old Viking data in the light of modern knowledge of extremophile forms of life has suggested that the Viking tests were not sophisticated enough to detect these forms of life, and may even have killed it in the testing procedure.^[2] The central idea here is that instead of being destroyed by Mars' high levels of hydrogen peroxide and other oxidants, life on Mars may use these chemicals to help them survive. For example hydrogen peroxide would stop water in a cell from freezing down to −50 °C and is hygroscopic, a useful trait on such a dry planet. The researchers cite Acetobacter peroxidans as a known example of a microbe that uses hydrogen peroxide in its metabolism. An extremophile is an organism, usually unicellular, which thrives in or requires extreme conditions that would exceed optimal conditions for growth and reproduction in the majority of mesophilic terrestrial organisms. ... A hygroscopic substance is a substance that absorbs water readily from its surroundings. ...

There are some that now argue that, if there was life at the Viking lander sites, it may have been killed by the exhaust from the landing rockets.^[3]

Modern findings

A series of artist's conceptions of hypothetical past water coverage on Mars.

Observations made in the late 1990s by the Mars Global Surveyor confirmed the suspicion that Mars, unlike Earth, no longer possessed a substantial global magnetic field, thus allowing potentially life-threatening cosmic radiation to reach the planet's surface. Scientists also speculate that the lack of shielding due to Mars's diminished global magnetic field helped the solar wind blow away much of Mars's atmosphere over the course of several billion years. Image File history File links History_of_water_on_Mars. ... Image File history File links History_of_water_on_Mars. ... The Mars Global Surveyor (MGS) was a US spacecraft developed by NASA and the Jet Propulsion Laboratory and launched November 1996. ... A magnetosphere is the region around an astronomical object in which phenomena are dominated or organized by its magnetic field. ... Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. ... The plasma in the solar wind meeting the heliopause The solar wind is a stream of charged particles (i. ... Mars, the fourth planet from the Sun, has a very different atmosphere from that of Earth. ...

Meteorites

In recent years speculation has grown as a result of studies of the ALH84001 Mars meteorite, which concluded that it contained fossilized microbes. Other scientists have subsequently sought to explain these findings on the basis of purely chemical processes. Both remain highly controversial within the scientific community. It has been suggested that other Mars meteorites such as the Nakhla meteorite have evidence of life also, but as of 2008 no convincing evidence has been forthcoming. Meteorite fragment ALH84001 ALH 84001 (Allan Hills 84001) is a meteorite found in Allan Hills, Antarctica in December 1984 by a team of US meteorite hunters from the ANSMET project. ... A Martian meteorite is a meteorite, that has landed on Earth but is believed to have originated from Mars. ... For other uses, see Fossil (disambiguation). ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... The Nakhla meteorite, the first and eponymous example of a Nakhlite type meteorite of the SNC Group type of meteorites, fell to Earth on the 28th of June, 1911, at approximately 09:00 in the Nakhla region of Abu Hommos, Alexandria, Egypt. ...

Extremophiles

Another suggestion of evidence for extremophiles on Mars comes from analysis of satellite images. It has been proposed that there is a biological origin for the annual appearance and disappearance of dark dune spots near the polar regions of Mars.^[4][5] An extremophile is an organism, usually unicellular, which thrives in or requires extreme conditions that would exceed optimal conditions for growth and reproduction in the majority of mesophilic terrestrial organisms. ...

Haloarchaea have been proposed as a kind of life that could live on Mars; because the Martian atmosphere has a pressure below the triple point of water, freshwater species would have no habitat.^[6] Haloarchaea are a member of the halophile community, in that they require high salt concentrations to grow. ...

Liquid water on Mars

No Mars probe since Viking has tested the Martian regolith directly for signs of life. NASA's recent missions have focused on another question: whether Mars held lakes or oceans of liquid water on its surface in the ancient past. Scientists have found hematite, a mineral that forms in the presence of water. Many scientists have long held this to be almost self-evident based on various geological landforms on the planet, but others have proposed different explanations—wind erosion, oxygen oceans, etc. Thus, the mission of the Mars Exploration Rovers of 2004 was not to look for present or past life, but for evidence of liquid water on the surface of Mars in the planet's ancient past. Regolith (Greek: blanket rock) is a layer of loose, heterogeneous material covering solid rock. ... For other uses, see Hematite (disambiguation). ... Artists Concept of Rover on Mars NASAs Mars Exploration Rover (MER) Mission (since 2003) is a unmanned Mars exploration mission that includes sending two Rovers (robots) to explore the Martian surface and geology. ...

In June 2000, evidence for water currently under the surface of Mars was discovered in the form of flood-like gullies.^[7] Deep subsurface water deposits near the planet's liquid core might form a present-day habitat for life. However, in March 2006, astronomers announced the discovery of similar gullies on the Moon,^[8] which is believed never to have had liquid water on its surface. The astronomers suggest that the gullies could be the result of micrometeorite impacts. Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ...

In March 2004, NASA announced that its rover Opportunity had discovered evidence that Mars was, in the ancient past, a wet planet.^[9] This had raised hopes that evidence of past life might be found on the planet today. Image File history File links Wateronmars. ... The launch patch for Opportunity, featuring Duck Dodgers (Daffy Duck). ...

In December 2006, NASA showed images taken by the Mars Global Surveyor that suggested that water occasionally flows on the surface of Mars. The images did not actually show flowing water. Rather, they showed changes in craters and sediment deposits, providing the strongest evidence yet that water coursed through them as recently as several years ago, and is perhaps doing so even now. Some researchers were skeptical that liquid water was responsible for the surface feature changes seen by the spacecraft. They said other materials such as sand or dust can flow like a liquid and produce similar results. The findings were published in the December 8, 2006 issue of the journal Science.^[10] The Mars Global Surveyor (MGS) was a US spacecraft developed by NASA and the Jet Propulsion Laboratory and launched November 1996. ... is the 342nd day of the year (343rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Science is the academic journal of the American Association for the Advancement of Science and is considered one of the worlds most prestigious scientific journals. ...

Methane on Mars

As methane cannot persist in the Martian atmosphere for more than a few hundred years, its presence suggests either that it is being replenished by some unidentified volcanic or geologic process, or that some kind of extremophile life form similar to some existing on Earth is metabolising carbon dioxide and hydrogen and producing methane. Methane is a chemical compound with the molecular formula . ... Mars, the fourth planet from the Sun, has a very different atmosphere from that of Earth. ... Cleveland Volcano in the Aleutian Islands of Alaska photographed from the International Space Station For other uses, see Volcano (disambiguation). ... An extremophile is an organism, usually unicellular, which thrives in or requires extreme conditions that would exceed optimal conditions for growth and reproduction in the majority of mesophilic terrestrial organisms. ... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... This article is about the chemistry of hydrogen. ...

In 1969, two scientists from the University of California at Berkeley, Dr. George C. Pimentel and Dr. Kenneth Herr, announced the discovery of methane and ammonia in the Martian atmosphere using Mariner 7 data. The report was withdrawn one month later due to the possibililty of misinterpretation of the absorption of similar specral bands by frozen carbon dioxide.^[11] George C. Pimentel (1922–1989) was the inventor of the chemical laser. ...

In March 2004, the orbiting ESA probe Mars Express reported detecting methane in the Martian atmosphere,^[12][13][14] which had earlier been suggested by observations of the United Kingdom Infrared Telescope on Hawaii and the Gemini South observatory in Chile in 2003.^[15] This article is about the European Space Agency. ... Concept model of the Mars Express spacecraft Main Engine Thrust for braking manouevre on Venus Express. ... Methane is a chemical compound with the molecular formula . ... UKIRT, the United Kingdom Infra-Red Telescope, is a 3. ... This article is about the U.S. State. ... The Gemini Observatory is an astronomical observatory consisting of 8-metre telescopes at two different sites. ...

Others have proposed that a process called serpentinization, wherein the mineral olivine is converted into serpentine in the presence of liquid water, may be occurring somewhere in the subsurface of Mars and releasing enough methane to explain the observations.^[16] Serpentinization is a geological metamorphic process involving heat and water in which low-silica mafic and ultramafic rocks are oxidized and hydrolyzed with water into serpentinite. ... The mineral olivine (also called chrysolite and, when gem-quality, peridot) is a magnesium iron silicate with the formula (Mg,Fe)2SiO4. ... For other uses, see Serpentine (disambiguation). ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ...

Formaldehyde on Mars

In February 2005, it was announced that the Planetary Fourier Spectrometer (PFS) on the European Space Agency's Mars Express Orbiter detected substantially more formaldehyde than anyone had reasonably expected, strongly pointing to other explanations such as microbial life. This claim continues to be widely debated in the scientific community.^[17] Scientists skeptical to the measurements say that the data from the PFS has been misinterpreted.^[18] ESA redirects here. ... Oblique view of the Reull Vallis near the Hellas basin, rendered from data obtained by the Mars Express orbiters High Resolution Stereo Camera (HRSC) The Mars Express Orbiter is part of the Mars Express program, a European Space Agency (ESA) mission to Mars. ... R-phrases , , , S-phrases , , , , , Flash point -53 °C Related Compounds Related aldehydes acetaldehyde benzaldehyde Related compounds ketones carboxylic acids Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Formaldehyde (methanal) is the chemical compound with the formula...

Ammonia on Mars

In the Martian atmosphere ammonia would be unstable and only last for a few hours. In fact a NASA scientist has said "There are no known ways for ammonia to be present in the Martian atmosphere that do not involve life".^[19] For this reason, the detection of ammonia would be extremely important for the debate of whether there is life on Mars. For other uses, see Ammonia (disambiguation). ...

In 1969, two scientists from the University of California at Berkeley, Dr. George C. Pimentel and Dr. Kenneth Herr, announced the discovery of methane and ammonia in the Martian atmosphere using Mariner 7 data. The report was withdrawn one month later due to the possibililty of misinterpretation of the absorption of similar specral bands by frozen carbon dioxide.^[20] George C. Pimentel (1922–1989) was the inventor of the chemical laser. ...

In July 2004 rumors began to circulate that Vittorio Formisano, the scientist in charge of the Planetary Fourier Spectrometer (PFS), would announce their discovery of ammonia at an upcoming conference. It later came to light that none had been found; in fact some noted that the PFS was not precise enough to distinguish ammonia from carbon dioxide anyway.^[21] An image of the interferometer used in the core of the Planetary Fourier Spectrometer. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ...

Silica on Mars

In May 2007, the Mars rover Spirit disturbed a patch of ground with its inoperative wheel that scientists say shows evidence of a past environment that would have been perfect for microbial life. The feature is reminiscent of the effect of hot spring water or steam coming into contact with volcanic rocks. On Earth, these are locations that tend to teem with bacteria, said rover chief scientist Steve Squyres. "We're really excited about this," he told a meeting of the American Geophysical Union (AGU). The area is extremely rich in silica — the main ingredient of window glass. The researchers have now concluded that the bright material must have been produced in one of two ways. One: hot-spring deposits produced when water dissolves silica at one location and then carries it to another (i.e a geyser). Two:an acidic steam rising through cracks in rocks and stripping them of their mineral components, apart from silica. "The important thing is that whether it is one hypothesis or the other, the implications for the former habitability of Mars are pretty much the same," Professor Squyres explained to BBC News. Hot water provides an environment in which microbes can thrive, and the precipitation of that silica entombs and preserves them. Squyres said "You can go to hot springs and you can go to fumaroles and at either place on Earth it is teeming with life — microbial life." ^[22][23] Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... The launch patch for Spirit, featuring Marvin the Martian. ... Steve Squyres Steven W. Squyres (b. ... The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... Strokkur geyser, Iceland A geyser is a type of hot spring that erupts periodically, ejecting a column of hot water and steam into the air. ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... Green Dragon Spring at Norris Geyser A hot spring is a place where warm or hot groundwater issues from the ground on a regular basis for at least a predictable part of the year, and is significantly above the ambient ground temperature (which is usually around 55~57 F or... “Solfatara” redirects here. ... A cluster of Escherichia coli bacteria magnified 10,000 times. ...

Phoenix lander, 2008

The Phoenix mission will land a telerobot in the polar region of Mars in May 2008. One of the mission's two primary objectives is to look for a 'habitable zone' in the Martian regolith where microbial life could exist(most likely alien lifeforms), the other mission being to study the geological history of water on Mars. The lander will have a 2.5 meter robotic arm that is capable of digging a 0.5 meter trench in the regolith. The arm is fitted with an arm camera that will be able to verify that there is material in the scoop when returning samples to the lander for analysis – this overcomes an important design flaw in the Viking landers. Phoenix is a robotic spacecraft on a space exploration mission to Mars under the Mars Scout Program. ... Regolith (Greek: blanket rock) is a layer of loose, heterogeneous material covering solid rock. ...

The craft has a mass spectrometer capable of detecting organic volatiles up to 10ppb, an optical microscope and an atomic force microscope. There is an electrochemistry experiment which will tell scientists about ions in the regolith and show the amount and type of antioxidants on Mars,^[24] if the device works. NASA scientist Carol Stoker reports that oxidants on Mars vary with latitude, noting that Viking 2 saw less oxidants than Viking 1 because of its more northerly position. Phoenix will land further north still .^[25] Rates of sedimentation at the Phoenix landing site are hoped to allow the probe to sample layers that date back at least 50,000 years, and maybe up to a million years. This is important because the climate of Mars has been much warmer in the past and any life could have been more active and widespread, says Stoker.

Unlike the Mars Pathfinder Sojourner rover and the Mars Exploration Rovers, which used airbag-cushioned capsules to land on Mars, the Phoenix lander will land the same way that the Viking landers did, despite the claims that rocket exhaust may have contaminated the Viking landing sites.^[3] The Mars Pathfinder was launched on December 4, 1996 by NASA aboard a Delta II just a month after the Mars Global Surveyor was launched. ... Artists Concept of Rover on Mars (credit: Maas Digital LLC) Marvin the Martian, Spirit rover Mission patch Duck Dodgers, Opportunity rover Mission patch NASAs Mars Exploration Rover (MER) Mission is an ongoing robotic mission of exploring Mars, that began in 2003 with the sending of two rovers â€” Spirit... For the Mozilla crash reporting software previously called Airbag, see Breakpad. ...

Some researchers claim in the book "Imminent Discovery"^[26] that the chances for Phoenix to find Martian life are very good, based on telescopic observations of pre-1965 astronomers. In his 1962 book "MARS, The Photographic Story", Earl C. Slipher describes "a dark bluish band that tightly hugs the border of the melting polar cap." (page 17). Phoenix should land in a location to resolve this mystery. Earl Charles Slipher (March 25, 1883 – August 7, 1964) was an American astronomer. ...

Other future missions

NASA is planning to launch the Astrobiology Field Laboratory in 2016, to help answer questions about life on Mars. The Mars Exploration and Payload Analysis Group is responsible for deciding what experiments will fly on the mission.^[27] The Astrobiology Field Laboratory is a proposed NASA unmanned planetary spacecraft to explore the planet Mars. ...

See also

• Planetary habitability
• Face on Mars
• Astronomy on Mars
• List of artificial objects on Mars
• Martian
• Terraforming
• Colonization of Mars
• Gillevinia straata
• Terraforming of Mars

Understanding planetary habitability is partly an extrapolation of the Earths conditions, as it is the only planet currently known to support life. ... Mars Orbital Cameras 2001 image of the face The Face on Mars is a large feature on the surface of the planet Mars located in the Cydonia region, thought by many to resemble a human face. ... This article presents information and images about viewing astronomical phenomena from the planet Mars. ... Artificial objects on Mars that are currently in use are the MER-A Spirit rover and the MER-B Opportunity rover. ... This article is about hypothetical native inhabitants of the planet Mars. ... Artists conception of a terraformed Mars in four stages of development. ... Mars Mars is the focus of much speculation and serious study about possible human colonization. ... It has been suggested that this article or section be merged with Life on Mars. ... Artists conception of the process of terraforming Mars Since the origin of the idea of terraforming, or changing a planets environment to produce a world that is habitable by humans, one of the primary subjects of study for potential terraforming has been the planet Mars. ...

References

is the 7th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 61st day of the year (62nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 7th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 151st day of the year (152nd in leap years) in the Gregorian calendar. ... PDF is an abbreviation with several meanings: Portable Document Format Post-doctoral fellowship Probability density function There also is an electronic design automation company named PDF Solutions. ... PDF is an abbreviation with several meanings: Portable Document Format Post-doctoral fellowship Probability density function There also is an electronic design automation company named PDF Solutions. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 76th day of the year (77th in leap years) in the Gregorian calendar. ... Science is the academic journal of the American Association for the Advancement of Science and is considered one of the worlds most prestigious scientific journals. ... For other uses, see NASA (disambiguation). ... The Associated Press, or AP, is an American news agency, the worlds largest such organization. ... is the 341st day of the year (342nd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... This article is about the European Space Agency. ... Science is the academic journal of the American Association for the Advancement of Science and is considered one of the worlds most prestigious scientific journals. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... is the 195th day of the year (196th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... For other uses, see BBC (disambiguation). ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 92nd day of the year (93rd in leap years) in the Gregorian calendar. ... For the Cornish painter, see Alfred Wallis. ...

External links

• Study Reveals Young Mars Was A Wet World
• NASA - The Mars Exploration Program
• Arthur C. Clarke sees life on Mars
• Scientists have discovered that Mars once had saltwater oceans
• BBC News: Methane on Mars could signal life
• BBC News: Ammonia on Mars could mean life
• Scientists say that life on Mars is likely today
• Ancient salty sea on Mars wins as the most important scientific achievement of 2004 - Journal Science
• Mars meteor found on Earth provides evidence that suggests microbial life once existed on Mars
• Scientific American Magazine (November 2005 Issue) Did Life Come from Another World?
• Audio interview about "Dark Dune Spots"
• Discussion of Phoenix's chances to find life on Mars

v • d • e Mars
Geography	General Albedo features (Solis Lacus) · Atmosphere · Canals (list) · Climate · Life · North Polar Basin · Chaos terrain Regions Cydonia Mensae · Planum Boreum · Planum Australe · Cerberus Hemisphere · Vastitas Borealis · Iani Chaos · Quadrangles · Tharsis · Ultimi Scopuli · Eridania Lake · Olympia Undae Mountains Listed by height · Echus Montes · Elysium Planitia Volcanoes Alba Patera · Albor Tholus · Arsia Mons · Ascraeus Mons · Biblis Patera · Elysium Mons · Hecates Tholus · Olympus Mons · Pavonis Mons · Syrtis Major · Tharsis · Tharsis Montes Craters Catenae · Hellas Planitia · Argyre Planitia · Schiaparelli · Gusev · Eberswalde · Eagle Geology Carbonates · Spherules · Spiders · Swiss cheese features Mars Portal
Moons	Phobos · Deimos Discovery · Features · Stickney crater (Phobos) · Phobos and Deimos in fiction
Meteorites	ALH84001 · Chassigny · Kaidun · Shergotty · Nakhla
Exploration	Colonization · Phobos program · Spirit-observed features · Opportunity-observed features · HiRISE · Manned mission · Mars landing · Mars rover · Artificial objects on Mars · Terraforming
Eclipses and transits	Eclipses Solar eclipses on Mars Transits Deimos · Phobos · Earth · Mercury · Venus
Other topics	Mars-crosser asteroid · Astronomy on Mars · Darian calendar · Timekeeping on Mars · Haughton-Mars Project · Martian · Mars Society · Flag of Mars · Mars in fiction