generic image
Processing...
  • Games
  • Catalog
  • Develop
  • Robux
  • Search in Players
  • Search in Games
  • Search in Catalog
  • Search in Groups
  • Search in Library
  • Log In
  • Sign Up
  • Games
  • Catalog
  • Develop
  • Robux
   
ROBLOX Forum » Roblox » All Things ROBLOX
Home Search
 

Re: Mars

Previous Thread :: Next Thread 
FlameingBird545 is not online. FlameingBird545
Joined: 26 Jul 2013
Total Posts: 345
03 Sep 2013 02:08 AM
ars is the fourth planet from the Sun and the second smallest planet in the Solar System. Named after the Roman god of war, it is often described as the "Red Planet" because the iron oxide prevalent on its surface gives it a reddish appearance.[14] Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the volcanoes, valleys, deserts, and polar ice caps of Earth. 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 of Olympus Mons, the second highest known mountain within the Solar System (the tallest on a planet), and of Valles Marineris, one of the largest canyons. The smooth Borealis basin in the northern hemisphere covers 40% of the planet and may be a giant impact feature.[15][16] Mars has two known moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids,[17][18] similar to 5261 Eureka, a Martian trojan asteroid.
Until the first successful Mars flyby in 1965 by Mariner 4, many speculated about the presence of liquid water on the planet's surface. This was based on observed periodic variations in light and dark patches, particularly in the polar latitudes, which appeared to be seas and continents; long, dark striations were interpreted by some as irrigation channels for liquid water. These straight line features were later explained as optical illusions, though geological evidence gathered by unmanned missions suggest that Mars once had large-scale water coverage on its surface.[19] In 2005, radar data revealed the presence of large quantities of water ice at the poles[20] and at mid-latitudes.[21][22] The Mars rover Spirit sampled chemical compounds containing water molecules in March 2007. The Phoenix lander directly sampled water ice in shallow Martian soil on July 31, 2008.[23]
Mars is currently host to five functioning spacecraft: three in orbit – the Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter – and two on the surface – Mars Exploration Rover Opportunity and the Mars Science Laboratory Curiosity. Defunct spacecraft on the surface include MER-A Spirit and several other inert landers and rovers such as the Phoenix lander, which completed its mission in 2008. Observations by the Mars Reconnaissance Orbiter have revealed possible flowing water during the warmest months on Mars.[24]
Mars can easily be seen from Earth with the naked eye, as can its reddish coloring. Its apparent magnitude reaches −3.0,[7] which is surpassed only by Jupiter, Venus, the Moon, and the Sun. Optical ground-based telescopes are typically limited to resolving features about 300 km (186 miles) across when Earth and Mars are closest because of Earth's atmosphere.[25]

Mars has approximately half the diameter of 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 of Earth's dry land.[6] While Mars is larger and more massive than Mercury, Mercury has a higher density. This results in the two planets having a nearly identical gravitational pull at the surface – that of Mars is stronger by less than 1%. The red-orange appearance of the Martian surface is caused by iron(III) oxide, more commonly known as hematite, or rust.[26] It can also look butterscotch,[27] and other common surface colors include golden, brown, tan, and greenish, depending on minerals.[27]
Internal structure
Like Earth, this planet has undergone differentiation, resulting in a dense, metallic core region overlaid by less dense materials.[28] Current models of the planet's interior imply a core region about 1794 km ± 65 km in radius, consisting primarily of iron and nickel with about 16–17% sulfur.[29] This iron sulfide core is partially fluid, and has twice the concentration of the lighter elements that exist at Earth's core. The core is surrounded by a silicate mantle that formed many of the tectonic and volcanic features on the planet, but now appears to be dormant. Besides silicon and oxygen, the most abundant elements in the Martian crust are iron, magnesium, aluminum, calcium, and potassium. The average thickness of the planet's crust is about 50 km, with a maximum thickness of 125 km.[30] Earth's crust, averaging 40 km, is only one third as thick as Mars's crust, relative to the sizes of the two planets. The InSight lander planned for 2016 will use a seismometer to better constrain the models of the interior.
Surface geology
Main article: Geology of Mars
Mars is a terrestrial planet that consists of minerals containing silicon and oxygen, metals, and other elements that typically make up rock. The surface of Mars is primarily composed of tholeiitic basalt,[31] although parts are more silica-rich than typical basalt and may be similar to andesitic rocks on Earth or silica glass. Regions of low albedo show concentrations of plagioclase feldspar, with northern low albedo regions displaying higher than normal concentrations of sheet silicates and high-silicon glass. Parts of the southern highlands include detectable amounts of high-calcium pyroxenes. Localized concentrations of hematite and olivine have also been found.[32] Much of the surface is deeply covered by finely grained iron(III) oxide dust.[33][34]
Although Mars has no evidence of a current structured global magnetic field,[35] observations show that parts of the planet's crust have been magnetized, and that alternating polarity reversals of its dipole field have occurred in the past. This paleomagnetism of magnetically susceptible minerals has properties that are very similar to the alternating bands found on the ocean floors of Earth. One theory, published in 1999 and re-examined in October 2005 (with the help of the Mars Global Surveyor), is that these bands demonstrate plate tectonics on Mars four billion years ago, before the planetary dynamo ceased to function and the planet's magnetic field faded away.[36]
During the Solar System's formation, Mars was created as the result of a stochastic process of run-away accretion out of the protoplanetary disk that orbited the Sun. Mars has many distinctive chemical features caused by its position in the Solar System. Elements with comparatively low boiling points such as chlorine, phosphorus and sulphur are much more common on Mars than Earth; these elements were probably removed from areas closer to the Sun by the young star's energetic solar wind.[37]


This Mars rock revealed its bluish-gray interior to Mars Science Laboratory[38]
After the formation of the planets, all were subjected to the so-called "Late Heavy Bombardment". About 60% of the surface of Mars shows a record of impacts from that era,[39][40][41] while much of the remaining surface is probably underlain by immense impact basins caused by those events. There is evidence of an enormous impact basin in the northern hemisphere of Mars, spanning 10,600 km by 8,500 km, or roughly four times larger than the Moon's South Pole – Aitken basin, the largest impact basin yet discovered.[15][16] This theory suggests that Mars was struck by a Pluto-sized body about four billion years ago. The event, thought to be the cause of the Martian hemispheric dichotomy, created the smooth Borealis basin that covers 40% of the planet.[42][43]
The geological history of Mars can be split into many periods, but the following are the three primary periods:[44][45]
Noachian period (named after Noachis Terra): Formation of the oldest extant surfaces of Mars, 4.5 billion years ago to 3.5 billion years ago. Noachian age surfaces are scarred by many large impact craters. The Tharsis bulge, a volcanic upland, is thought to have formed during this period, with extensive flooding by liquid water late in the period.
Hesperian period (named after Hesperia Planum): 3.5 billion years ago to 2.9–3.3 billion years ago. The Hesperian period is marked by the formation of extensive lava plains.
Amazonian period (named after Amazonis Planitia): 2.9–3.3 billion years ago to present. Amazonian regions have few meteorite impact craters, but are otherwise quite varied. Olympus Mons formed during this period, along with lava flows elsewhere on Mars.
Some geological activity is still taking place on Mars. The Athabasca Valles is home to sheet-like lava flows up to about 200 Mya. Water flows in the grabens called the Cerberus Fossae occurred less than 20 Mya, indicating equally recent volcanic intrusions.[46] On February 19, 2008, images from the Mars Reconnaissance Orbiter showed evidence of an avalanche from a 700 m high cliff.[47]
Soil
Main article: Martian soil


Exposure of silica-rich dust uncovered by the Spirit rover
The Phoenix lander returned data showing Martian soil to be slightly alkaline and containing elements such as magnesium, sodium, potassium and chlorine. These nutrients are found in gardens on Earth, and are necessary for growth of plants.[48] Experiments performed by the Lander showed that the Martian soil has a basic pH of 8.3, and may contain traces of the salt perchlorate.[49][50]
Streaks are common across Mars and new ones appear frequently on steep slopes of craters, troughs, and valleys. The streaks are dark at first and get lighter with age. Sometimes, the streaks start in a tiny area which then spread out for hundreds of metres. They have also been seen to follow the edges of boulders and other obstacles in their path. The commonly accepted theories include that they are dark underlying layers of soil revealed after avalanches of bright dust or dust devils.[51] Several explanations have been put forward, some of which involve water or even the growth of organisms.[52][53]
Hydrology
Report Abuse
FlameingBird545 is not online. FlameingBird545
Joined: 26 Jul 2013
Total Posts: 345
03 Sep 2013 02:09 AM
The very first word is Mars
Report Abuse
USMCkabar is not online. USMCkabar
Joined: 21 Oct 2007
Total Posts: 20648
03 Sep 2013 02:09 AM
Welcome to All Things Off Topic.

Take a read of this: http://www.roblox.com/Forum/ShowPost.aspx?PostID=111762135
Report Abuse
Previous Thread :: Next Thread 
Page 1 of 1
 
 
ROBLOX Forum » Roblox » All Things ROBLOX
   
 
   
  • About Us
  • Jobs
  • Blog
  • Parents
  • Help
  • Terms
  • Privacy

©2017 Roblox Corporation. Roblox, the Roblox logo, Robux, Bloxy, and Powering Imagination are among our registered and unregistered trademarks in the U.S. and other countries.



Progress
Starting Roblox...
Connecting to Players...
R R

Roblox is now loading. Get ready to play!

R R

You're moments away from getting into the game!

Click here for help

Check Remember my choice and click Launch Application in the dialog box above to join games faster in the future!

Gameplay sponsored by:
Loading 0% - Starting game...
Get more with Builders Club! Join Builders Club
Choose Your Avatar
I have an account
generic image