إعـــــــلان

**طائر المساء** · 09-03-2010, 04:46 PM

المشاركة الأصلية بواسطة Fattema

الف شكر لك اخوي طائر المساء , كلك ذوق ,

من غير اعتذار واسف ياخوي , مقدرين لكم ظروفكم ,

وانا بانتظار التكلمة ترى !!!

سلمكم الله تعالى ووفقكم لكل خير ,

أشكركم كثيرا اختي فاطمة لتفهمكم حفظكم الله وبارك بكم

ان شاء الله سأضع بعد قليل تكملة وهي جزئية خاصة بما يُعرف بـ الكواكب الداخلية في المجموعة الشمسية

مرفقة بالعديد من الصور الجميلة والرائعة للكواكب

**طائر المساء** · 09-03-2010, 04:47 PM

المشاركة الأصلية بواسطة انصار الصدر00

nice picture

شكرا لكم الأخ الكريم انصار الصدر عالمرور

**طائر المساء** · 09-03-2010, 06:08 PM

Inner Solar System
The inner Solar System is the traditional name for the region comprising the terrestrial planets and asteroids. Composed mainly of silicates and m etals, the objects of the inner Solar System are relatively close to the Sun; the radius of this entire region is shorter than the distance between Jupiter and Saturn.

Inner planets
The four inner or terrestrial planets have dense, rocky compositions, few or no moons, and no ring systems. They are composed largely of refractory minerals, such as the silicates which form their crusts and mantles, and m etals such as iron and nickel, which form their cores. Three of the four inner planets (Venus, Earth and Mars) have atmospheres substantial enough to generate weather; all have impact craters and tectonic surface features such as rift valleys and volcanoes. The term inner planet should not be confused with inferior planet, which designates those planets which are closer to the Sun than Earth is (i.e. Mercury and Venus).

Mercury
Mercury (0.4 AU from the Sun) is the closest planet to the Sun and the smallest planet in the Solar System (0.055 Earth masses). Mercury has no natural satellites, and its only known geological features besides impact craters are lobed ridges or rupes, probably produced by a period of contraction early in its history. Mercury's almost negligible atmosphere consists of atoms blasted off its surface by the solar wind. Its relatively large iron core and thin mantle have not yet been adequately explained. Hypotheses include that its outer layers were stripped off by a giant impact, and that it was prevented from fully accreting by the young Sun's energy.

MESSENGER false color image of Mercury

Venus
Venus (0.7 AU from the Sun) is close in size to Earth, (0.815 Earth masses) and like Earth, has a thick silicate mantle around an iron core, a substantial atmosphere and evidence of internal geological activity. However, it is much drier than Earth and its atmosphere is ninety times as dense. Venus has no natural satellites. It is the hottest planet, with surface temperatures over 400 °C, most likely due to the amount of greenhouse gases in the atmosphere. No definitive evidence of current geological activity has been detected on Venus, but it has no magnetic field that would prevent depletion of its substantial atmosphere, which suggests that its atmosphere is regularly replenished by volcanic eruptions.

Venus in real color

Earth

Earth (1 AU from the Sun) is the largest and densest of the inner planets, the only one known to have current geological activity, and is the only place in the universe where life is known to exist. Its liquid hydrosphere is unique among the terrestrial planets, and it is also the only planet where plate tectonics has been observed. Earth's atmosphere is radically different from those of the other planets, having been altered by the presence of life to contain 21% free oxygen. It has one natural satellite, the Moon, the only large satellite of a terrestrial planet in the Solar System.

High-resolution global composites of Moderate Resolution Imaging Spectroradiometer

Mars

Mars (1.5 AU from the Sun) is smaller than Earth and Venus (0.107 Earth masses). It possesses an atmosphere of mostly carbon dioxide with a surface pressure of 6.1 millibars (roughly 0.6 percent that of the Earth's). Its surface, peppered with vast volcanoes such as Olympus Mons and rift valleys such as Valles Marineris, shows geological activity that may have persisted until as recently as 2 million years ago. Its red colour comes from iron oxide (rust) in its soil. Mars has two tiny natural satellites (Deimos and Phobos) thought to be captured asteroids.

Mars in 2001 as seen by the Hubble Space Telescope

Rock strewn surface imaged by Mars Pathfinder

Asteroid belt
Asteroids are mostly small Solar System bodies composed mainly of refractory rocky and m etallic minerals.
The main asteroid belt occupies the orbit between Mars and Jupiter, between 2.3 and 3.3 AU from the Sun. It is thought to be remnants from the Solar System's formation that failed to coalesce because of the gravitational interference of Jupiter.
Asteroids range in size from hundreds of kilometres across to microscopic. All asteroids save the largest, Ceres, are classified as small Solar System bodies, but some asteroids such as Vesta and Hygieia may be reclassed as dwarf planets if they are shown to have achieved hydrostatic equilibrium.
The asteroid belt contains tens of thousands, possibly millions, of objects over one kilometre in diameter. Despite this, the total mass of the main belt is unlikely to be more than a thousandth of that of the Earth. The main belt is very sparsely populated; spacecraft routinely pass through without incident. Asteroids with diameters between 10 and 10−4 m are called meteoroids.

Image of the main asteroid belt and the Trojan asteroids

Ceres

Ceres (2.77 AU) is the largest body in the asteroid belt and is classified as a dwarf planet. It has a diameter of slightly under 1000 km, and a mass large enough for its own gravity to pull it into a spherical shape. Ceres was considered a planet when it was discovered in the 19th century, but was reclassified as an asteroid in the 1850s as further observation revealed additional asteroids. It was again reclassified in 2006 as a dwarf planet.

Asteroid groups
Asteroids in the main belt are divided into asteroid groups and families based on their orbital characteristics. Asteroid moons are asteroids that orbit larger asteroids. They are not as clearly distinguished as planetary moons, sometimes being almost as large as their partners. The asteroid belt also contains main-belt comets which may have been the source of Earth's water.
Trojan asteroids are located in either of Jupiter's L4 or L5 points (gravitationally stable regions leading and trailing a planet in its orbit); the term "Trojan" is also used for small bodies in any other planetary or satellite Lagrange point. Hilda asteroids are in a 2:3 resonance with Jupiter; that is, they go around the Sun three times for every two Jupiter orbits.

The inner Solar System is also dusted with rogue asteroids, many of which cross the orbits of the inner planets.

This picture of 433 Eros shows the view looking from one end of the asteroid across the gouge on its underside and toward the opposite end. Features as small as 35 m (115 ft) across can be seen.

Ceres (bottom left), the Moon and the Earth, shown to scale

To Be Continued

**Fattema** · 09-03-2010, 09:34 PM

Well-done ! Fantastic post,indeed

I enjoyed reading it .

Thanks a lot dear brother 6a2er Al-Masa2

Waiting for more... till the end..Ummmmm

**طائر المساء** · 12-03-2010, 03:17 PM

المشاركة الأصلية بواسطة Fattema

Well-done ! Fantastic post,indeed

I enjoyed reading it .

Thanks a lot dear brother 6a2er Al-Masa2

Waiting for more... till the end..Ummmmm

I'm so glad you enjoy reading my posts my dear sister Fattema

Let's go now to the next part

It is about outer solar system

I hope you will enjoy this post too

May Allah (s.w.t) Reward you and Protect you

Respect & Regards

**طائر المساء** · 12-03-2010, 04:39 PM

Outer Solar System
The outer region of the Solar System is home to the gas giants and their large moons. Many short period comets, including the centaurs, also orbit in this region. Due to their greater distance from the Sun, the solid objects in the outer Solar System contain more ices (such as water, ammonia, methane, often called ices in planetary science) than the rocky denizens of the inner Solar System, as the colder temperatures allow these compounds to remain solid.

From top to bottom: Neptune, Uranus, Saturn, and Jupiter (not to scale)

Outer planets
The four outer planets, or gas giants (sometimes called Jovian planets), collectively make up 99 percent of the mass known to orbit the Sun. Jupiter and Saturn are each many tens of times the mass of the Earth and consist overwhelmingly of hydrogen and helium; Uranus and Neptune are far less massive (<20 Earth masses) and possess more ices in their makeup. For these reasons, some astronomers suggest they belong in their own category, “ice giants.” All four gas giants have rings, although only Saturn's ring system is easily observed from Earth. The term outer planet should not be confused with superior planet, which designates planets outside Earth's orbit and thus includes both the outer planets and Mars.

Jupiter
Jupiter (5.2 AU), at 318 Earth masses, is 2.5 times all the mass of all the other planets put together. It is composed largely of hydrogen and helium. Jupiter's strong internal heat creates a number of semi-permanent features in its atmosphere, such as cloud bands and the Great Red Spot.

Jupiter has 63 known satellites. The four largest, Ganymede, Callisto, Io, and Europa, show similarities to the terrestrial planets, such as volcanism and internal heating. Ganymede, the largest satellite in the Solar System, is larger than Mercury.

This image was enhanced by the U.S. Geological Survey to bring out detail. It is based on a 1979 image from the Voyager 1 spacecraft

Approximate size comparison of Earth and Jupiter, including the Great Red Spot

Saturn
Saturn (9.5 AU), distinguished by its extensive ring system, has several similarities to Jupiter, such as its atmospheric composition and magnetosphere. Although Saturn has 60% of Jupiter's volume, it is less than a third as massive, at 95 Earth masses, making it the least dense planet in the Solar System.

Saturn has 62 confirmed satellites; two of which, Titan and Enceladus, show signs of geological activity, though they are largely made of ice. Titan, the second largest moon in the Solar System, is larger than Mercury and the only satellite in the Solar System with a substantial atmosphere.

Saturn, as seen by Cassini

A rough comparison of the sizes of Saturn and Earth

Uranus
Uranus (19.6 AU), at 14 Earth masses, is the lightest of the outer planets. Uniquely among the planets, it orbits the Sun on its side; its axial tilt is over ninety degrees to the ecliptic. It has a much colder core than the other gas giants, and radiates very little heat into space.
Uranus has 27 known satellites, the largest ones being Titania, Oberon, Umbriel, Ariel and Miranda.

Uranus, as seen by Voyager 2

Size comparison of Earth and Uranus

Neptune
Neptune (30 AU), though slightly smaller than Uranus, is more massive (equivalent to 17 Earths) and therefore more dense. It radiates more internal heat, but not as much as Jupiter or Saturn.
Neptune has 13 known satellites. The largest, Triton, is geologically active, with geysers of liquid nitrogen. Triton is the only large satellite with a retrograde orbit. Neptune is accompanied in its orbit by a number of minor planets, termed Neptune Trojans, that are in 1:1 resonance with it.

Neptune from Voyager 2

A size comparison of Neptune and Earth

Comets
Comets are small Solar System bodies, typically only a few kilometres across, composed largely of volatile ices. They have highly eccentric orbits, generally a perihelion within the orbits of the inner planets and an aphelion far beyond Pluto. When a comet enters the inner Solar System, its proximity to the Sun causes its icy surface to sublimate and ionise, creating a coma: a long tail of gas and dust often visible to the naked eye.

Short-period comets have orbits lasting less than two hundred years. Long-period comets have orbits lasting thousands of years. Short-period comets are believed to originate in the Kuiper belt, while long-period comets, such as Hale-Bopp, are believed to originate in the Oort cloud. Many comet groups, such as the Kreutz Sungrazers, formed from the breakup of a single parent. Some comets with hyperbolic orbits may originate outside the Solar System, but determining their precise orbits is difficult. Old comets that have had most of their volatiles driven out by solar warming are often categorised as asteroids.

Centaurs
The centaurs are icy comet-like bodies with a semi-major axis greater than Jupiter (5.5 AU) and less than Neptune (30 AU). The largest known centaur, 10199 Chariklo, has a diameter of about 250 km. The first centaur discovered, 2060 Chiron, has also been classified as comet (95P) since it develops a coma just as comets do when they approach the Sun.

Comet Hale-Bopp

To Be Continued

**طائر المساء** · 12-03-2010, 05:01 PM

Trans-Neptunian region
The area beyond Neptune, or the "trans-Neptunian region", is still largely unexplored. It appears to consist overwhelmingly of small worlds (the largest having a diameter only a fifth that of the Earth and a mass far smaller than that of the Moon) composed mainly of rock and ice. This region is sometimes known as the "outer Solar System", though others use that term to mean the region beyond the asteroid belt.

Kuiper belt
The Kuiper belt, the region's first formation, is a great ring of debris similar to the asteroid belt, but composed mainly of ice. It extends between 30 and 50 AU from the Sun. It is composed mainly of small Solar System bodies, but many of the largest Kuiper belt objects, such as Quaoar, Varuna, and Orcus, may be reclassified as dwarf planets. There are estimated to be over 100,000 Kuiper belt objects with a diameter greater than 50 km, but the total mass of the Kuiper belt is thought to be only a tenth or even a hundredth the mass of the Earth. Many Kuiper belt objects have multiple satellites, and most have orbits that take them outside the plane of the ecliptic.

The Kuiper belt can be roughly divided into the "classical" belt and the resonances. Resonances are orbits linked to that of Neptune (e.g. twice for every three Neptune orbits, or once for every two). The first resonance begins within the orbit of Neptune itself. The classical belt consists of objects having no resonance with Neptune, and extends from roughly 39.4 AU to 47.7 AU. Members of the classical Kuiper belt are classified as cubewanos, after the first of their kind to be discovered, (15760) 1992 QB1, and are still in near primordial, low-eccentricity orbits.

Plot of all known Kuiper belt objects, set against the four outer planets

Pluto and Charon
Pluto (39 AU average), a dwarf planet, is the largest known object in the Kuiper belt. When discovered in 1930, it was considered to be the ninth planet; this changed in 2006 with the adoption of a formal definition of planet. Pluto has a relatively eccentric orbit inclined 17 degrees to the ecliptic plane and ranging from 29.7 AU from the Sun at perihelion (within the orbit of Neptune) to 49.5 AU at aphelion.

It is unclear whether Charon, Pluto's largest moon, will continue to be classified as such or as a dwarf planet itself. Both Pluto and Charon orbit a barycenter of gravity above their surfaces, making Pluto-Charon a binary system. Two much smaller moons, Nix and Hydra, orbit Pluto and Charon.

Pluto has a 3:2 resonance with Neptune, meaning that Pluto orbits twice round the Sun for every three Neptunian orbits. Kuiper belt objects whose orbits share this resonance are called plutinos.

Computer-generated map of Pluto from Hubble images, synthesised true colour[note 1] and among the highest resolutions possible with current technology

Pluto's volume is about 0.66% that of Earth

Haumea and Makemake
Haumea (43.34 AU average), and Makemake (45.79 AU average), while smaller than Pluto, are the largest known objects in the classical Kuiper belt (that is, they are not in a confirmed resonance with Neptune). Haumea is an egg-shaped object with two moons. Makemake is the brightest object in the Kuiper belt after Pluto. Originally designated 2003 EL61 and 2005 FY9 respectively, they were given names and designated dwarf planets in 2008. Their orbits are far more inclined than Pluto's, at 28° and 29°.

Scattered disc
The scattered disc, which overlaps the Kuiper belt but extends much further outwards, is thought to be the source of short-period comets. Scattered disc objects are believed to have been ejected into erratic orbits by the gravitational influence of Neptune's early outward migration. Most scattered disc objects (SDOs) have perihelia within the Kuiper belt but aphelia as far as 150 AU from the Sun. SDOs' orbits are also highly inclined to the ecliptic plane, and are often almost perpendicular to it. Some astronomers consider the scattered disc to be merely another region of the Kuiper belt, and describe scattered disc objects as "scattered Kuiper belt objects." Some astronomers also classify centaurs as inward-scattered Kuiper belt objects along with the outward-scattered residents of the scattered disc.

Eris
Eris (68 AU average) is the largest known scattered disc object, and caused a debate about what constitutes a planet, since it is at least 5% larger than Pluto with an estimated diameter of 2400 km (1500 mi). It is the largest of the known dwarf planets. It has one moon, Dysnomia. Like Pluto, its orbit is highly eccentric, with a perihelion of 38.2 AU (roughly Pluto's distance from the Sun) and an aphelion of 97.6 AU, and steeply inclined to the ecliptic plane.

Comparison of Eris, Pluto, Makemake, Haumea, Sedna, Orcus, 2007 OR10, Quaoar, and Earth (all to scale).

Artist impression of Eris and Dysnomia. Eris is the main object, Dysnomia the small grey disk just above it. The flaring object top-left is the Sun.

To Be Continued

**Fattema** · 12-03-2010, 09:55 PM

**Fattema** · 12-03-2010, 10:29 PM

!! Bravo dear brother 6a2er Al-Masa

What a wonderful sharing ! Full of great & interesting information

Waiting for the continuation

Have a great day

**baan** · 14-03-2010, 08:58 PM

أحسنتَ يا أخي الوفي طائر المساء

what can I say when I see my good brother did
all his best to let us read such a brilliant topic
Good bless you
my I wish you success in your life
and joy in your heart
best regards

your sister
baan

**feras** · 14-03-2010, 11:05 PM

Good bless you

Let me correct this for you grand mother

it is better to say Allah instade of God.

I wish you all the best mom..

**Fattema** · 15-03-2010, 02:05 PM

المشاركة الأصلية بواسطة feras

Let me correct this for you grand mother

it is better to say Allah instade of God.

I wish you all the best mom..

Sorry for interference !

But allow me to correct you this

It's " instead " not " instade " ..Do you see what I mean?

Regards

**feras** · 15-03-2010, 03:14 PM

المشاركة الأصلية بواسطة Fattema

Sorry for interference !

But allow me to correct you this

It's " instead " not " instade " ..Do you see what I mean?

Regards

---------

ok teacher

it was a spelling mistake. I was concentrating on the meaning and forgot the spelling itself .. sorry boss

I know it is a lesson learn.

**baan** · 15-03-2010, 05:17 PM

المشاركة الأصلية بواسطة feras

Let me correct this for you grand mother

it is better to say Allah instade of God.

I wish you all the best mom..

all right my good grandson
I'll correct it as you like
May Allah Bless you
are you

Satisfied now

**baan** · 15-03-2010, 05:21 PM

المشاركة الأصلية بواسطة Fattema

Sorry for interference !

But allow me to correct you this

It's " instead " not " instade " ..Do you see what I mean?

Regards

well done dear fattema

regards

إعـــــــلان

للاشتراك في (قناة العلم والإيمان): واتساب - يوتيوب

The Solar System

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اقرأ في منتديات يا حسين