Subscribe Now
Buy deviantWEAR
Advertise Here
[x]
All Deviations

Solar System - Mars by ~astronomy-lovers:iconastronomy-lovers:

Categories Literature > Prose > Non-Fiction > General Non-Fiction




Mars is the fourth planet from the Sun and the seventh largest:

* orbit: 227,940,000 km (1.52 AU) from Sun
* diameter: 6,794 km
* mass: 6.4219e23 kg

Mars has been known since prehistoric times. It is still a favorite of science fiction writers as the most favorable place in the Solar System (other than Earth!) for human habitation. But the famous "canals" "seen" by Lowell and others were, unfortunately, just as imaginary as Barsoomian princesses.

Spacecrafts to visit Mars:

*Mariner 4 (1965)
*Vikings landers (1976)
*Mars Pathfinder (July 4, 1997)
*Mars Expedition Rovers "Spirit" and "Opportunity" (2004)

Mars' orbit is elliptical, so there exists a temperature variation of about 30 C at the subsolar point between aphelion and perihelion. This has a major influence on Mars' climate. While the average temperature on Mars is about 218 K (-55 C, -67 F), Martian surface temperatures range widely from as little as 140 K (-133 C, -207 F) at the winter pole to almost 300 K (27 C, 80 F) on the day side during summer.

Except for Earth,  Mars has the most highly varied and interesting terrain of any of the terrestrial planets, some of it quite spectacular:

* Olympus Mons: the largest mountain in the Solar System. High: 24 km (78,000 ft.) above the surrounding plain; Base: 500 km in diameter and is rimmed by a cliff 6 km (20,000 ft) high.
* Tharsis: a huge bulge on the Martian surface that is about 4000 km across and 10 km high.
Valles Marineris: a system of canyons 4000 km long and from 2 to 7 km deep.
* Hellas Planitia: an impact crater in the southern hemisphere over 6 km deep and 2000 km in diameter.

The interior of Mars is known only by inference from data about the surface and the bulk statistics of the planet. The most likely scenario is a dense core about 1700 km in radius, a molten rocky mantle somewhat denser than the Earth's and a thin crust. Like Mercury and the Moon, Mars appears to lack active plate tectonics at present; there is no evidence of recent horizontal motion of the surface such as the folded mountains so common on Earth.

There is very clear evidence of erosion in many places on Mars including large floods and small river systems. At some time in the past there was clearly some sort of fluid on the surface. Liquid water is the obvious fluid but other possibilities exist. There may have been large lakes or even oceans; the evidence for which was strenghtened by some very nice images of layered terrain taken by Mars Global Surveyor. But it seems that this occurred only briefly and very long ago; the age of the erosion channels is estimated at about nearly 4 billion years. (Valles Marineris was NOT created by running water. It was formed by the stretching and cracking of the crust associated with the creation of the Tharsis bulge.)

Mars has a very thin atmosphere composed mostly of the tiny amount of remaining carbon dioxide (95.3%) plus nitrogen (2.7%), argon (1.6%) and traces of oxygen (0.15%) and water (0.03%). The average pressure on the surface of Mars is only about 7 millibars (less than 1% of Earth's), but it varies greatly with altitude from almost 9 millibars in the deepest basins to about 1 millibar at the top of Olympus Mons. But it is thick enough to support very strong winds and vast dust storms that on occasion engulf the entire planet for months. Mars' thin atmosphere produces a greenhouse effect but it is only enough to raise the surface temperature by 5 degrees (K); much less than what we see on Venus and Earth.

Mars has permanent ice caps at both poles composed of water ice and solid carbon dioxide (dry ice). The ice caps exhibit a layered structure with alternating layers of ice with varying concentrations of dark dust. In the northern summer the carbon dioxide completely sublimes, leaving a residual layer of water ice. It seems likely that a similar layer of water ice exists below the southern cap as well. The mechanism responsible for the layering is unknown but may be due to climatic changes related to long-term changes in the inclination of Mars' equator to the plane of its orbit. There may also be water ice hidden below the surface at lower latitudes. The seasonal changes in the extent of the polar caps changes the global atmospheric pressure by about 25%.

Large, but not global, weak magnetic fields exist in various regions of Mars. This unexpected finding made by Mars Global Surveyor just days after it entered Mars orbit. They are probably remnants of an earlier global field that has since disappeared. This may have important implications for the structure of Mars' interior and for the past history of its atmosphere and hence for the possibility of ancient life.

When it is in the nighttime sky, Mars is easily visible with the unaided eye. Its apparent brightness varies greatly according to its relative position to the Earth. There are several Web sites that show the current position of Mars (and the other planets) in the sky. More detailed and customized charts can be created with a planetarium program such as Starry Night.

Mars' Satellites: Mars has two tiny satellites which orbit very close to the martian surface:

Phobos:
Distance: 9.000Km
Radius: 11Km
Mass: 1.08e16Kg
Discoverer: Hall
Date: 1877

Deimos:
Distance: 23Km
Radius: 6Km
Mass: 1.80e15Kg
Discoverer: Hall
Date: 1877

The distance is from the center of the planet
©2004-2008 ~astronomy-lovers
Details
Submitted: February 21, 2004
File Size: 5.9 KB
Image Size: 16.3 KB
Resolution: 500×500
Comments: 1
Favourites & Collections: 1 [who?]

Views
Total: 76
Today: 1

Downloads
Total: 50
Today: 0

Thumb

Author's Comments

The 4th planet rom the Sun, Mars is very misterious, because exist the possibility for have life :O_o:

Note: This deviation is ONLY for documental purposes :!::!::!::!::!:

Previous deviations:
:bulletblue: The Sun
:bulletblue: Mercury
:bulletblue: Venus
:bulletblue: Earth

Image is © by Nasa
[x]

Devious Comments

love 0 0 joy 0 0 wow 0 0 mad 0 0 sad 0 0 fear 0 0 neutral 0 0

~olieviya:iconolieviya: Feb 21, 2004, 7:58:19 AM
Who took this photo?
Who wrote this text?

--
I'm hungry
Previous Page        Next Page
Sign up to leave feedback! <3
©2008 deviantART. All rights reserved
About Us | Contact Us | Help & FAQ Advertise | Services Etiquette | Privacy Policy | Terms of Service | Copyright Policy