THE INNER PLANETS
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The inner planets also called Rocky planets, freeing ourselves from the Sun, they are Mercury, Venus, Earth and Mars (figure left). They are smaller than external planets, and consist mostly of rocks, sand and dust. They may not have the atmosphere and do not have rings.

   

                                                        MERCURY

 

 

mass

3.3 1023 kg /0.055 M

Rotation period (sidereal day)

58.65 Dt

Equatorial Radius

2439.7 km

Solar Revolution period

87,969 Dt

Volume

0.07 1023cm3/0.054 Vt

Solar day period (two sunrises later)

175.97 Dt

Acceleration due to gravity

2.78 m/s2

 

 

Average temperature during the day

427° c

 

 

Average temperature at night

-173° c

Satellites

None

Average speed orbital

47.9 km/s

Atmosphere

Gaseous veil due to solar wind He(43%)Na (42%) Or (14%)

Perihelion orbit

45.9 106 km

Inclination of the Equator compared to orbit

Aphelion orbit

69.7 106 km

 

 

Eccentricity of the orbit

0.2056

 

 

Orbital inclination  respect to the ecliptic

 

 

Mercury is the smallest planet in the solar system similar in appearance to the moon. Low gravity don't allows it to have an atmosphere but being near the Sun Mercury is surrounded by a thin veil gaseous (α particles) due to the strong solar wind. It has been previously targeted by many meteorites due to its proximity to the Sun. Slowly rotates around its own axis and around the Sun. This causes large variations in excess of 500° c. With a weak magnetic field it has a core very large made primarily of iron and nickel (approximately 80% of the total volume) wrapped in a mantle and a crust.

  

                                                           VENUS

 

mass

4.90 1024 kg /Mt 0.8149

Retrograde rotation period (sidereal day)

243.02 Dt

Equatorial Radius

6052 miles

Solar Revolution period

224.7 Dt

Volume

0.95 1027cm3/0.84 Vt

Solar day period (two sunrises later)

116.75 Dt

Acceleration due to gravity

8.87 m/s2

 

 

Average temperature of the clouds

-30° c

 

 

Average temperature of the soil

480° c

Satellites

None

Average speed orbital

35.03 km/s

Atmosphere

CO2 (96%) N (3%)

Perihelion orbit

107.4 106 km

Inclination of the Equator compared to orbit

177° 3 '

Aphelion orbit

109 106 km

 

 

Eccentricity of the orbit

0.0068

 

 

Orbital inclination  respect to the ecliptic

 

 

 

                                                

Venus is similar in size to Earth and is enveloped by a thick atmosphere that don't allows us to observe its surface. It has a retrograde rotation so the sun rises in the West and sets in the East. The atmosphere is approximately 90 km thick and is formed for the 96% of carbon dioxide that develops a greenhouse gases with about 500° C average temperature and sea level pressure 90 times greater than terrestrial. It has clouds composed of sulfuric acid, suspended at 50 km. The planet revolves slowly around its axis (Venusian day lasts 243 terrestrial days). The weak ground wind gradually becomes stronger at high altitudes with speeds of 400 km/h for which tall layers of clouds make the full turn of the planet in 4 days. The Venusian surface is less hospitable due to high temperatures and a thick fog of light little gas with possibility of acid rain. There isn't a magnetic field registered.

                                                  EARTH  

 

mass

5.9742 1024 kg

Rotation period (sidereal day)

23.9345 hours

Equatorial Radius

6378.388 km

Solar Revolution period

365.26 days

Volume

10 108,32110 km3

Solar day period (two sunrises later)

24 hours

Acceleration due to gravity

9.8 m/s2

 

 

Minimum temperature

-88° c

 

 

Maximum temperature

58° c

Satellites

1 – the Moon

Average speed orbital

29.8 km/s

Atmosphere

N2 (78%), O2 (21%), Ar, CO2, He, He, ...

Perihelion orbit

1.4709 108 km

Inclination of Equator  respect to the ecliptic

23° 27 '

Aphelion orbit

1,521 108 km

 

 

Eccentricity of the orbit

0.0167

 

 

Orbital inclination  respect to the ecliptic

 

 

The Earth is composed of concentric layers rocks of different composition, density and temperature, separated by surfaces of discontinuity. The surface is called the Earth's crust consists of plates in slow motion of aftershocks (seismic motions) where there are the land (continents) and surface water (oceans). Than continents are in motion and it is believed to come from the separation of a single continent called Pangea. Water is present in the liquid state (seas), solid (glaciers, polar ice) and steam (atmosphere). Under the crust there are layers called top and bottom Mantle with gradual increase of density of rocks and in general the temperature reaching 5000° C in the lower mantle. Progressing deeper into the Core, it' is divided into two parts called internal and outer core. The inner core has a Rocky density 5 times higher than the crust and 10000° C temperatures. The Earth is a very dynamic planet where everything moves at different speeds as the clouds, the winds, the seas, the continents, the volcanoes, glaciers, ... The atmosphere that envelops the planet is divided into several layers. Proceeding from the ground there is the Troposphere with a thickness that varies from 18 Km at equator to 6 Km at the poles. It is home to virtually all weather phenomena that relate to meteorology with changes in the density of various chemical components and a temperature down to about - 55° c. Climbing through the Tropopause which is home to strong winds, we meet the stratosphere. In the stratosphere just a few thin clouds, that is home to a layer of ozone (O3) and the temperature rises to reach 60° C at a height of 55 Km. So the Stratopause and above there is the Mesosphere where the temperature drops down to - 90° C up to 85 Km. Finally the thermosphere, where the temperature rises past the 100° C at a height of 500 km. The Exosphere is the wide border zone where the Earth gravitational works. The Earth is the only place known at the moment where life was born and evolved . The Moon is its only satellite and the man on July 20, 1969 with Apollo 11 mission of  NASA has conducted the first landing.

             

                                 Nearside Face

                                                    MOON

 

Mass

7.4 × 1024 Kg

Average distance from Earth

384400 Km

Volume

2.2 x 1010 Km3

Inclination of the orbit on the ecliptic

5° 9 '

Gravity

1.6338 m /s2

Inclination of the axis of rotation in the plane of the orbit

6° 41 '

Equatorial Radius

1738 Km

Eccentricity of the orbit

0.055

 

                     Surface

             The Moon face not visible from Earth

The Moon is the only natural satellite of the Earth and with it form a system in which reciprocal interactions give rise to phenomena such as the tides on Earth. It consists of a central core surrounded by a thick fluid mantle solid/liquid. All wrapped up by a thin solid mantle of approximately 150 Km and a solid crust stable large 7 Km. The appearance of the surface is desert, sandy and part of it rocky (depicted by astronauts like a magnificent desolation). The craters are due to impacts with celestial objects such as meteorites, asteroids that have taken place in billions of years and not by movements of the crust that is stable. It has atmosphere and view the Earth always the same face as his time and direction of rotation are equal to the period and to the direction of revolution around the Earth. The Moon describes an ellipse around the Earth in one of two fires point, with the same sense of rotation and terrestrial revolution. The sidereal month of 27.32 days is the time the Moon takes to complete one full revolution orbiting the Earth. The phases of the Moon represent the appearance of the Moon in different States of solar lighting and depend on relative position Sun Earth Moon. The Synodic month of 29.53 days called lunation solar is the time that elapses between two identical phases. 

Photo NASA credit

Mars is 9 times smaller than Earth, has a low gravity that allows it to have a rarefied atmosphere mostly composed of CO2 that solidifies the Poles forming larger ice caps during the winter. The day and the seasons are similar to those in terrestrial life but with lower temperatures. There are frequent and vast dust storms in a rocky desert environment that gives it a reddish color due to the pilaster oxide present in the sand. After the Moon, Mars is the most studied celestial body from various probes of space agencies. It is thought that the subsoil may contain water. However he has never found any trace of a vital process. It has three moons: Phobos (25 km in diameter), Deimos (13 km) and Gaspa that would be three meteors.

      From left: Gaspa, Phobos, Deimos

                                                        MARS

 

mass

6.42 1023 kg /M 0.108

Rotation period (sidereal day)

24.62 hours

Equatorial Radius

3397 km

Solar Revolution period

687 days ago

Volume

0.16 1027 cm3 /0.15 M

Solar day period (two sunrises later)

24,660 hours

Acceleration due to gravity

3.8 m/s2

 

 

Minimum temperature

-140° c

 

 

Maximum temperature

20° c

Satellites

3

Average speed orbital

24.1 km/s

Atmosphere

N2 (2.7%), Ar (1.6%), CO2 (95%)

Perihelion orbit

2,067 108 km

Tilt the equator respect to the orbit

24° 11 '

Aphelion orbit

2,491 108 km

 

Eccentricity of the orbit

0.0934

 

 

Orbital inclination  respect to the ecliptic

1.85°

 

 

 
        Below an example of the Martian landscape

 
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