Mars is the Fourth Planet From the Sun in the Solar System

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Transcript of Mars is the Fourth Planet From the Sun in the Solar System

  • 8/2/2019 Mars is the Fourth Planet From the Sun in the Solar System


    Mars is the fourthplanet from theSunin the Solar System. Named after the Romangod of war,Mars, it is often described as the "Red Planet" as theiron oxide prevalent on its surface gives it areddish appearance.[13] Mars is a terrestrial planetwith a thinatmosphere, having surface featuresreminiscent both of the impact craters of the Moon and the volcanoes, valleys, deserts, andpolarice capsofEarth. The rotational period and seasonal cycles of Mars are likewise similar to those

    of Earth, as is the tilt that produces the seasons. Mars is the site ofOlympus Mons, the highestknown mountain within the Solar System, and ofValles Marineris, the largest canyon. ThesmoothBorealis basin in the northern hemisphere covers 40% of the planet and may be a giantimpact feature.[14][15]

    Until the first successful flyby of Mars occurred in 1965, by Mariner 4, many speculated aboutthe presence of liquid water on the planet's surface. This was based on observed periodicvariations in light and dark patches, particularly in the polarlatitudes, which appeared to be seasand continents; long, darkstriations were interpreted by some as irrigation channels for liquidwater. These straight line features were later explained asoptical illusions, though geologicalevidence gathered by unmanned missions suggest that Mars once had large-scale water coverageon its surface.[16] In 2005, radar data revealed the presence of large quantities of water ice at the


    and at mid-latitudes.[18][19]

    The Mars roverSpiritsampled chemical compoundscontaining water molecules in March 2007. ThePhoenix lander directly sampled water ice inshallow Martian soil on July 31, 2008.[20]

    Mars has two moons, Phobos andDeimos, which are small and irregularly shaped. These may becaptured asteroids, similar to5261 Eureka, a Martian trojan asteroid. Mars is currently host tothree functional orbiting spacecraft: Mars Odyssey, Mars Express, and the Mars ReconnaissanceOrbiter. On the surface are the Mars Exploration RoverOpportunity and its recentlydecommissioned twin, Spirit, along with several other inert landers and rovers, both successfuland unsuccessful. ThePhoenix lander completed its mission on the surface in 2008.Observations byNASA's now-defunctMars Global Surveyorshow evidence that parts of thesouthern polar ice cap have been receding.[21] Observations by the Mars Reconnaissance Orbiter

    have revealed possible flowing water during the warmest months on Mars.


    Mars can easily be seen from Earth with the naked eye. Itsapparent magnitude reaches 3.0[7] abrightness surpassed only by Jupiter, Venus, the Moon, and the Sun. Optical ground basedtelescopes are typically limited to resolving features about 300 km (186 miles) across when Earthand Mars are closest, because of Earth's atmosphere.[23]


    1 Physical characteristics

    1.1 Geology

    1.2 Soil

    1.3 Hydrology

    1.3.1 Polar caps

    1.4 Geography

    1.4.1 Impact topography
  • 8/2/2019 Mars is the Fourth Planet From the Sun in the Solar System


    1.4.2 Tectonic sites

    1.4.3 Caves

    1.5 Atmosphere

    1.6 Climate

    2 Orbit and rotation

    3 Moons

    4 Search for life

    5 Exploration missions

    5.1 Current missions

    5.2 Past missions

    5.3 Future missions

    5.4 Manned mission goals

    6 Astronomy on Mars

    7 Viewing

    7.1 Closest approaches

    7.1.1 Relative

    7.1.2 Absolute, around the present time

    7.2 Historical observations

    7.3 Martian "canals"

    8 In culture

    8.1 Intelligent "Martians" 9 Surface details

    10 Exploration timeline

    11 See also

    12 Notes

    13 References

    14 External links

    Physical characteristics

  • 8/2/2019 Mars is the Fourth Planet From the Sun in the Solar System


    Size comparison ofEarth and Mars.

    Mars has approximately half the diameterof Earth. It is less dense than Earth, having about 15%of Earth's volume and 11% of the mass. Its surface area is only slightly less than the total area ofEarth's dry land.[6] While Mars is larger and more massive than Mercury, Mercury has a higherdensity. This results in the two planets having a nearly identical gravitational pull at the surfacethat of Mars is stronger by less than 1%. The red-orange appearance of the Martian surface iscaused by iron(III) oxide, more commonly known as hematite, or rust.[24]


    Main article: Geology of Mars

    Mars is a terrestrial planetthat consists of minerals containing siliconandoxygen, metals, andother elements that typically make up rock. The surface of Mars is primarily composed oftholeiiticbasalt,[25]although parts are more silica-rich than typical basalt and may be similar toandesitic rocks on Earth or silica glass. Regions of low albedoshow concentrations ofplagioclase feldspar, with northern low albedo regions displaying higher than normalconcentrations of sheet silicates and high-silicon glass. Parts of the southern highlands includedetectable amounts of high-calciumpyroxenes. Localized concentrations ofhematite and olivinehave also been found.[26]Much of the surface is deeply covered by finely grainediron(III) oxide


    Like Earth, this planet has undergone differentiation, resulting in a de