شَمسِي سِرِشتو

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شمسي سرشتي جو خاڪو (درست پيماني تي نھ)

شمسي سرشتو مشتمل آھي ڌرتي' سِجَ ۽ retinue of celestial وٿُون ثقلاً واڙيل آھن. روايتاً، ھيءُ تي ٻڌل سمجھيو ويندو آھي. سِجُ، نَوَ گرھھ ۽ سندن 158 ھن وقت معلوم چَنڊُ؛ ، جو ھڪ وڏو تعداد ٻيون وٿون، سميت گِرَھڙيون، meteoroid، planetoid، پُڇُڙ تارا، ۽ بين الگرھياتي ڌوڙ, مدارُ سج پڻ. نجمدانَ ڪنھن ڏھين گرھھ جي موجودگيءَ تي بحث ڪري رھيا آھن.

Although the term "شمسي سرشتو" آھي ڪثرتاً applied to other نَجِمِي سرشتو ۽ گِرَھياتِي سرشتا which may comprise them, it should strictly refer to Earth's سرشتو بال خصوص: لفظ "شَمسِي" آھي derived from the Sun's لاطيني نالو، Sol, ۽ تنھنڪري وارو اصطلاح ڪڏھن ڪڏھن appears as شمسي سرشتو. بابت ڳالھائيندي وقت ٻيو نجماتي سرشتو يا گرھياتي سرشتو، سميت تارا ۽ اجسام لاڳاپيل with them through ثقل، it is usual to shorten it to drop the term "نَجِمِياتِي" and form names such as "the اَلفا سينٽارِي سرشتو" يا "51 پيگاسِي سرشتو".

[edit] شمسي سرشتي جِي ڙجڪَ ۽

The سِجُ (astronomical symbol ☉) is a main sequence G2 تارو that contains 99.86% of the system's known مايو. ان جا ٻھ وڏي ۾ وڏا مداريندڙ اجسام، Jupiter ۽ Saturn, account for more than 90% of the remainder; the Oort Cloud might hold a substantial سيڪڙو، but as yet its وجود آھي غير يقيني.

وسيع معنيٰ ۾، the charted regions of the شمسي سرشتو تي ٻڌل ٿي ٿو سج ۽ نا جو گِرَھياتِي سرشتو: the اَٺَ اجسام in نسبتاً unique مدارَ عام طور سڏجندڙ گِرَھَھ or مُکُ گِرَھَھ and two پَٽيُون of ننڍڙا objects, جنھن کي سڏ سگھجي ٿو ننڍ گِرَھَھ، planetoids، meteoroids، يا planetesimal. Pluto، نائون گرھھ، is also considered a member of the outer پٽيءَ، ۽ ان جو status is فال وقت غير يقيني, particularly since the دريافت جو 2003 UB₃₁₃ (ھيٺ ڏسندا). Most objects in مدار round the Sun all lie within the same shallow plane, called the بيضوي سنواٽو، ۽ مدار ۾ the ساڳي رُخَ. Many آھن in turn orbited by چَنڊs, and the largest are encircled by گرھياتي ڇَلا جي ڌوڙ ۽ ٻيا ذرڙات.

مُکُ گرھھ، ترتيبوار، Mercury (☿)، Venus (♀)، ڌرتي (♁)، مريخ (♂)، Jupiter (♃)، Saturn (♄)، Uranus (♅/)، Neptune (♆)، ۽ Pluto (♇) آھن. اٺن تي the نون گرھن نالا رکيل آھن مان ديوتائن ۽ ديوين Greco-رومن mythology.

فاصلا اندر the شمسي سرشتي are measured most often in نجمياتي ايڪا، يا AU. ھڪ AU ڌرتي ۽ سج درميان سراسري فاصلو آھي، يعني 149 598 000 ڪلوميٽر. عام طور استعمال ٿيندڙ ٻين ايڪن ۾اچي وڃن ٿا the gigametre (Gm، ڏھھ لکَ ڪلوميٽر) ۽ terametre (Tm، ھڪ ارب/milliard ڪلوميٽر). Pluto آھي اٽڪل 38 AU (5.9 Tm) سج کان، جڏھن تھ Jupiter lies at roughly 5.2 AU (778 Gm).

ھيءَ تصوير illustrating the مدار جو Sedna gives a good idea جو the layout of the شمسي سرشتي. Clockwise from top کاٻو: the اندريون شمسي سرشتو، the ٻاھريان گرھھ ۽ the Kuiper belt، the مدار جو Sedna ۽ the Oort Cloud.

باوجود ان حقيقت تھ جي many diagrams represent the شمسي سرشتو as having each مدار the same فاصلو apart, in actuality the orbits are largely arranged geometrically, that is, each is roughly double the فاصلو from the سج as the one before it. Venus’s distance from the سِجُ is roughly ٻيڻو that of Mercury, ڌرتي’s فاصلو آھي roughly جي فاصلي کان ٻيڻو Venus, مريخ’s double that of ڌرتي etc. This relationship is expressed in the Titius-Bode قاعدو, a رياضياتِي formula for predicting the semi-major axes of planets in AU. In its simplest form, it is written:

جڏھن تھ k=0, 1, 2, 4, 8, 16, 32, 64, 128.

By this formulation, one would expect Mercury's مَدارُ (k=0) to be 0.4 AU, ۽ مريخ's مدار (k=4) to be at 1.6 AU. In fact their مدارَ are 0.38 ۽ 1.52 AU.Ceres، the largest asteroid، lies at k=8.

ھيءُ قاعدو آھي only a rough guide, and doesn't fit all گرھن جو؛ Neptune آھي گھڻو ويجھو کان قڳڪٿيل, though Pluto lies at Neptune's predicted مدار. As of now, there is no سائنسي explanation for why this قاعدو applies، ۽ many claim it is محض ھڪ اتفاق، falling into the علائقي of uncomfortable سائنس.

[edit] شمسِي سرشتي جِي ڄَمارَ ۽ ابتدا

Using radiometric dating, scientists can estimate that the solar system is 4.6 billion years old. The oldest rocks on Earth are approximately 3.9 billion years old. Rocks this old are rare, as the Earth's surface is constantly being reshaped by erosion, vulcanism and plate tectonics. To estimate the age of the solar system scientists must use meteorites, which were formed during the early condensation of the solar nebula. The oldest meteorites (such as the Canyon Diablo meteorite) are found to have an age of 4.6 billion years, hence the solar system must be at least 4.6 billion years old.

ھاڻوڪو نظريو of شمسي سرشتي جي جڙڻ بابت the nebular hypothesis, پھريون نظريو آھي، جيڪو 1755ع ڌاري Immanuel Kant ۽ Pierre-Simon Laplace الڳ الڳ پيش ڪيو. nebular نظريو has been refined over many years and now has a great deal ofحق ۾ ڪيتريون ئي وڏيون ثابتيون آھن.

To briefly summarize, the nebular نظريي مطابق that the شمسي سرشتو مان ٺھيو ھو the ثقلي collapse of a گيسي بادل called the solar nebula. It had a diameter of 100 نجميا and was 2-3 times the mass of the Sun. Over time a disturbance (possibly a nearby supernova) squeezed the nebula, pushing matter inward until gravitational forces overcame the internal gas pressure and it began to collapse. As the nebula collapsed it began to spin faster to conserve angular momentum، ۽ became warmer. As the competing forces associated with gravity, gas pressure, magnetic fields, and rotation acted on it the contracting nebula began to flatten into a spinning protoplanetary disk with a gradually contracting protostar at the center.

Grains of dust (silicates and metals) and ice (hydrogen compounds) condensed from the gas, and began to accrete into larger and larger clumps, forming planetesimals. Inside the frost line, planetesimals were composed of rock and metal, because those are the only grains that can condense at those temperatures, and remained relatively small because they were only 0.6% the mass of the disk. The larger icy planetesimals beyond the frost line became massive enough to capture and hold onto helium and then hydrogen gases, which caused them to rapidly grow into jovian protoplanets.

10 ڪروڙ سالن کان پوءِ، the pressure and density of hydrogen in the centre of the collapsing nebula became great enough for the protosun to begin thermonuclear fusion, which increased until hydrostatic equilibrium was achieved. The young Sun's شمسي واءُ then cleared away all the gas and dust in the protoplanetary disk, blowing it into بين نجماتي پولار، thus ending the اوڌ جي the گرھن .

[edit] شمسي سرشتي جا علائقا

Heliospheric current sheet، وڏي ۾ وڏو structure in the شمسي سرشتو، results from the influence of the سج's rotating مقنائي اَڇَ تي the plasma in the بين الگرھياتي ذريعو (شمسي واءُ) [1]. (وڏو ڪرڻ لاءِ ڪلڪ ڪريو)

سندن مڪانيت پٽاندر، اسان جي شمسي سرشتي جون وٿون آھن divided into ٽن zones: Zone I or the اندريون شمسي سرشتو، including terrestrial گرھھ ۽ the Main belt of asteroids; Zone II, including the giant planets, their اپگرھھ and the centaurs، ۽ Zone III, يا the ٻاھريون شمسي سرشتو، comprising the area of the Trans-Neptunian objects including the Kuiper Belt، the Oort cloud، ۽ the وسيع علائقي ۾ درميان.

[edit] بين الگرَھياتِي ذريعو

The ماحول in which the solar system resides is called the بينُ الگِرَھياتِي ذَرِيعو. The سِجُ ڪِرِڻي ٿو a لڳاتار stream of charged particles، a plasma known as شَمسِي واءُ, which forms a very tenuous "فضا" (the heliosphere)، permeating the بينُ الگِرَھياتِي ذَرِيعو in all directions for at least ten اَرب (10×10⁹) miles (16 Tm or 16×10⁹ km) into space. Small quantities of dust are also present in the بينُ الگِرَھياتِي ذَرِيعو ۽ are responsible for the phenomenon of zodiacal light. Some of the dust is likely بين النجماتِي ڌُوڙ from outside the شمسي سرشتو. The influence of the Sun's rotating مَقِنائِي اَڇَ on the بينُ الگِرَھياتِي ذَرِيعو creates the largest structure in the شمسي سرشتو، the heliospheric current sheet.

[edit] داخلِي گِرَھَھ

The four inner or terrestrial planets are characterised by their dense, rocky composition, lack of ابتدائي فضائُون, and few or no چنڊ or ring systems. They formed in the hotter regions سجَ جي ويجھو، where hydrogen compounds remained gaseous, leaving only those mineral dust grains with high melting points such as silicates to form the planets' solid crusts ۽ semi-liquid mantles, and metallic dust grains such as فولادُ, which forms their cores. All have impact craters ۽ many possess tectonic surface features, such as rift valleys and ٻرندڙ جبل. The term اندريون گرھھ should not be confused with inferior planet، which designates those planets which lie اندر the ڌرتيءَ جي مدار (thus Mercury and Venus only).

ڌار اندريان گرھھ ھي آھن:

ڌرتي اندرين گِرَھن ۾ وڏي کان وڏو گرھھ آھي

• Mercury (0.39 AU from the Sun): The closest planet to the Sun is also the smallest and most atypical of the inner planets, having no atmosphere and, to date, no observed geological activity save that produced by impacts. Its relatively large iron core suggests that it was once a much larger world whose outer mantle was sheared off in early formation by the Sun’s gravity.

• Venus (0.72 AU): The first truly terrestrial planet, Venus, like the ڌرتِي، possesses a thick silicate mantle around an iron core, as well as a substantial فضا ۽ ثابتِي of one-time داخلي ڀون ڀياسِي activity، جھڙوڪ ٻرندڙ جبل. It is گھڻو وڏيڪ خشڪ کان ڌرتي، however; its فضا is 90 times as گھاٽو ۽ composed overwhelmingly of ڪاربان dioxide with traces of sulfuric acid.

• ڌرتِي with چَنڊُ (1 AU): The largest and densest of the inner planets، ڌرتي is also the only one to demonstrate unequivocal ثابتِي جِي جارِي ڀون ڀياسي activity. Its liquid hydrosphere، unique among the terrestrials, is probably the سبب why Earth is also the only planet where multi-plate tectonics has been observed, since پاڻي acts as a lubricant for subduction. Its atmosphere is radically different from the other terrestrials, having been altered by the حياتيءَ جي موجودگي to contain 21 percent free oxygen. Its اپگرھھ، the چنڊ، is sometimes considered a terrestrial planet in a سھمدار with its partner، since its orbit around the سج never actually loops back on itself when observed from above. The چنڊ possesses many of the features in common with other terrestrial گرھھ، though it lacks an iron core.

• مريخ (1.5 AU): کان ننڍا the ڌرتي or Venus, مريخ possesses a tenuous فضا of ڪاربان ڊاءِ آڪسائيڊ. Its surface, peppered with vast volcanoes and rift valleys such as Valles Marineris، shows that it was once geologically active and recent evidence [2] suggests it may have continued to be so until very recently. Mars possesses two tiny چنڊs thought to be captured asteroids.

[edit] گِرَھڙياتِي پَٽِي

Asteroids are objects smaller than planets that mostly occupy the orbit between Mars and Jupiter, between 2.3 and 3.3 AU from the Sun, and are composed in significant part of non-volatile minerals. The main asteroid belt contains tens of thousands (possibly millions) of asteroids over 1 km across, though they can be as small as dust. Despite their large numbers, the total mass of the main asteroid belt is unlikely to be more ھڪ ھزارين ڀاڱي کانthat the ڌرتيءَ جي. Asteroids with a diameter of less than 50 m are called meteoroids. The largest asteroid, Ceres, has a diameter of roughly 1000 km; large enough to be spherical, which would make it a گرھھ by some definitions of the word.

The asteroids are thought to be the remnants of a small terrestrial planet that failed to coalesce due to the gravitational interference of Jupiter.

They are subdivided into asteroid groups and families based on their specific 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.

Trojan asteroids are located in either of Jupiter's L₄ or L₅ points, though the term is also sometimes used for asteroids in any other planetary Lagrange point as well.

The asteroid belt also contains main-belt comets [3] which may have been the source of Earth's water.

The inner solar system is dusted with rogue asteroids, many of which cross the orbits of the inner planets.

[edit] خارجِي گِرَھَھ

The four ٻاھريان گرھھ, or gas giants, (sometimes called Jovian planets) are so large they collectively make up 99 percent of the mass known to orbit the سج. Their large sizes and distance from the Sun meant they could hold on to much of the hydrogen and helium too light for the smaller and hotter terrestrial planets to retain. The term ٻاھريان گرھھ should not be confused with superior planet, which designates those planets which lie outside ڌرتي's orbit (thus consisting of the outer planets plus Mars).

اسان جي شمسي سرشتي اندر وڏو ۾ وڏو گرھھ Jupiter آھي.

• Jupiter (5.2 AU), at 318 Earth masses, is 2.5 times the mass of all the other planets put together. Its composition of largely hydrogen and helium is not very different from that of the Sun. Three of its 63 اُپگرھھ, Ganymede, Io and Europa, share elements in common with the terrestrial planets, such as volcanism and internal heating. Jupiter has a faint, smoky ring. Jupiter's intense gravitational pull attracts many comets, and may have played a role in lowering the number of impacts Earth has experienced in its history.

• Saturn (9.5 AU), famous for its extensive ring system, shares many qualities in common with Jupiter, including its atmospheric composition, though it is far less massive, being only 95 Earth masses. Two of its 49 moons, Titan and Enceladus, show signs of geological activity, though they are largely made of ice. Titan is the only satellite in the solar system with a substantial atmosphere.

• Uranus (19.6 AU) and Neptune (30 AU), while having many characteristics in common with the other gas giants, are nonetheless more similar to each other than they are to Jupiter or Saturn. They are both substantially smaller, being only 14 and 17 Earth masses, respectively. Their atmospheres contain a smaller percentage of hydrogen and helium, and a higher percentage of “ices”, such as water, ammonia and methane. For this reason some astronomers suggested that they belong in their own category, “Uranian planets,” or “ice giants.” Both planets possess dark, insubstantial ring systems. Neptune’s largest moon Triton is geologically active.

Centaurs are icy comet-like bodies that have less-eccentric orbits so that they remain in the region between Jupiter and Neptune. The first centaur to be discovered, 2060 Chiron, has been called a comet since it has been shown to develop a tail, or coma, just as comets do when they approach the sun.

[edit] The trans-Neptunian region

The area beyond Neptune, often referred to as the outer solar system or simply the "trans-Neptunian region", is still largely unexplored.

[edit] The Kuiper belt

This region's first formation, which actually begins inside the orbit of Neptune, is the Kuiper belt, a great ring of debris, similar to the asteroid belt but composed mainly of ice and far greater in extent, which lies between 30 and 50 AU from the Sun. This region is thought to be the place of origin for short-period comets, such as Halley's comet. Though there are estimated to be over 70,000 Kuiper belt objects with a diameter greater than 100 km, the total mass of the Kuiper belt is relatively low, perhaps equalling or just exceeding the mass of the Earth. Many Kuiper belt objects have orbits that take them outside the plane of the ecliptic.

[edit] Pluto

• Pluto, the solar system's smallest planet, is considered to be part of the Kuiper Belt population. Like others in the belt, it has a relatively eccentric orbit inclined 17 degrees to the ecliptic and ranging from 29.7 AU from the Sun at perihelion to 49.5 AU at aphelion. It has a large moon (the largest in the solar system relative to its own size), called Charon, and, new observations suggest, two other, much smaller moons. Like the Earth/Moon, Pluto and Charon are often considered a double planet. Although accepted by the public as a planet since its discovery in 1930, Pluto's tiny mass (less than 1% of Earth's) and diameter have regularly sparked debates about Pluto's identity within the scientific community.

Kuiper belt objects with Pluto-like orbits are called Plutinos. Other Kuiper belt objects have resonant orbits and are grouped accordingly. The remaining Kuiper belt objects, in more "classical" orbits, are classified as Cubewanos.

The Kuiper Belt has a very sharply defined edge. At around 49 AU, a sharp dropoff occurs in the number of objects observed. This dropoff is known as the "Kuiper Cliff", and as yet its cause is unknown. Some speculate that something must exist beyond the belt large enough to sweep up the remaining debris, perhaps as large as Earth or Mars. This view is still controversial, however.

[edit] پکڙيل ڊسڪ

Overlapping the Kuiper belt but extending much further outwards is the scattered disc. Scattered disc objects are believed to have been originally native to the Kuiper belt, but were ejected into erratic orbits in the outer fringes.

[edit] 2003 UB₃₁₃

One particular scattered disc object, originally found in 2003 but confirmed two years later by Mike Brown (Caltech), David Rabinowitz (Yale University), and Chad Trujillo (Gemini Observatory), has renewed the old debate about what constitutes a planet since it is ~30% larger than Pluto with an estimated diameter of 3000 km (1900 miles). It currently has no name, but has been given the provisional designation 2003 UB₃₁₃, and has been nicknamed "Xena" by its discoverers, after the television character. It has many similarities with 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 is steeply inclined to the ecliptic plane, at 44 degrees, more so than any known object in the solar system except the newly-discovered object 2004 XR₁₉₀. Like Pluto, it is believed to consist largely of rock and ice, and has a moon [4]. Whether it and the largest Kuiper belt objects should be considered planets or whether instead Pluto should be reclassified as a minor planet has not yet been resolved.

[edit] ھِڪَ نئين علائقي جو امڪانُ

Sedna, the newly discovered Pluto-like object with a gigantic, highly elliptical 10,500-year orbit that takes it from about 76 to 928 AU, has too distant a perihelion to be a scattered member of the Kuiper Belt and could be the first in an entirely new population. 2000 CR₁₀₅ is also believed to be a member of this population.

[edit] پُڇُڙُ تارا

Comets are composed largely of volatile ices and have highly eccentric orbits, generally having a perihelion within the orbit of the inner planets and an aphelion far beyond Pluto. Short-period comets exist with apoapses closer than this, however, and old comets that have had most of their volatiles driven out by solar warming are often categorized as asteroids. Long period comets have orbits lasting thousands of years. Some comets with hyperbolic orbits may originate outside the solar system.

[edit] پرانھان ترين علائقا

The point at which the solar system ends and interstellar space begins is not precisely defined, since its outer boundaries are delineated by two separate forces: the solar wind and the Sun's gravity.

The Voyagers entering the heliosheath

The heliosphere expands outward in a great bubble to about 95 AU, or three times the orbit of Pluto. The edge of this bubble is known as the termination shock; the point at which the solar wind collides with the opposing winds of the interstellar medium. Here the wind slows, condenses and becomes more turbulent, forming a great oval structure known as the heliosheath that looks and behaves very much like a comet's tail; extending outward for a further 40 AU at its stellar-windward side, but tailing many times that distance in the opposite direction. The outer boundary of the sheath, the heliopause, is the point at which the solar wind finally terminates, and one enters the environment of interstellar space. Beyond the heliopause, at around 230 AU, lies the bow shock, a plasma "wake" left by the Sun as it travels through the Milky Way.

But even this point is not classified as outside the solar system, for the Sun's gravity will still hold sway even up to the Oort cloud, which is a great mass of icy objects, currently hypothetical, believed to be the source for all long-period comets and to surround the solar system like a shell from 50,000 to 100,000 AU beyond the Sun, or almost halfway to the next star system. The vast majority of the solar system, therefore, is completely unknown.

[edit] اسان جو شمسي سرشتو ڪھڪشائين جي پس منظر ۾

The solar system is located in the Local Fluff in the Orion Arm of the کِيرائِين واٽَ ڪھڪشان, a گھنڊيدار ڪھڪشان with a قطر of about 100,000 نُوري سالs containing تقريباً 200 ارب تارا، of which the سج is a rather large and bright one. The vast majority of تارن آھن red dwarfs; the سج is placed near the middle of the Hertzsprung-Russell diagram، پر stars larger and hotter than it are rare, whereas تارا dimmer and cooler than it are very common، although we can observe only those few other red dwarfs that are very near the سج ۾ خلا.

اندازا place the شمسي سرشتو at درميان 25,000 ۽ 28,000 نُورِي سالَ from the ڪھڪشائين مرڪز. Its speed is about 220 ڪلوميٽر في سيڪنڊ, and it completes one revolution every 226 ملين سال. At the galactic مڪانيت of the شمسي سرشتو، the escape velocity with regard to the ثقل جو کِيرائِين واٽَ آھي اٽڪل 1000 ڪلوميٽر في سيڪنڊ.

The شمسي سرشتو appears to have a very unusual orbit. It is both extremely close to being circular, and at nearly the exact distance at which the orbital speed matches the speed of the compression waves that form the spiral arms. The solar system appears to have remained between spiral arms for most of the existence of life on Earth. The radiation from supernovae in spiral arms could theoretically sterilize planetary surfaces, preventing the formation of large animal life on land. By remaining out of the spiral arms, Earth may be unusually free to form large animal life on its surface.

For many years, the solar system had the only گرھياتي سرشتو known, and so theories of planetary formation only had to explain one system to be plausible. The discovery in recent years of many extrasolar planets has uncovered systems very different compared to Earth's solar system, and theories have had to be revised accordingly. For instance, many extrasolar planetary systems contain a "hot Jupiter"; a planet of comparable size to Jupiter that nonetheless orbits very close to its star, at, for instance, 0.05 AU. It has been hypothesised that while the giant planets in these systems formed in the same place as the gas giants in Earth's solar system did, some sort of migration took place which resulted in the giant planet spiralling in towards the parent star. Any terrestrial planets which had previously existed would presumably either be destroyed or ejected from the system.

See main article: extrasolar planet

[edit] شمسي سرشتي جي کوجَ

ڪيترن ئي ھزارن سالن تائين، ڪجھھ نامور شخصيات کي ڇڏي، باقي ماڻھو شمسي سرشتي جي وجود ۾ يقين نھ رکندا ھئا. ڌرتي لاءِ يقين ڪيو ويندو ھو تھ اھا نھ رڳو ڪائنات جي مرڪز ۾ سِٿَلَ آھي، بلڪھ "رولُو تارن" کان مختلف (گرھھ) جيڪي آسمان ۾ ڀٽڪندا رھن ٿا. The conceptual advances of the 17ھين صدي, led by نڪولس ڪوپرنيڪس, گالِيليئو گالِيليئِي, جوھينز ڪيپلر، ۽ اسحاق نيوٽن، led gradually to the acceptance of the idea not only that ڌرتي سج جي چوڌاري گردش ڪري رھي آھي، مگر that the گرھھ were goverened by the ساڳيا قاعدا that governed the ڌرتي, ۽ تنھنڪري could be similar to it. The پھرين کوج جي the شمسي سرشتي was conducted by ڏور ويک (دور بين), with astronomers learning that the چنڊُ and other گرھھ possessed such ڌرتيءَ نما features as craters, ice caps، ۽ مندون.

See main article: ڀون پيمائي ماڊل

Since the start of the خلائي دور, a great deal of کوج has been performed by unmanned space missions that have been organized and executed by various space agencies. The first probe to land on another solar system body was the Soviet Union's Luna 2 probe, which impacted on the چنڊ in 1959. Since then, increasingly distant planets have been reached, with probes landing on Venus in 1965, Mars in 1976, the asteroid 433 Eros in 2001, and Saturn's moon Titan in 2005. خلائي رٿ have also made close approaches to other planets: Mariner 10 passed Mercury in 1973.

پھرين probe کوجڻ لاءِ the outer planets was Pioneer 10, which flew by Jupiter in 1973. Pioneer 11 was the first to visit Saturn, in 1979. The Voyager probes performed a grand tour of the outer planets following their launch in 1977, with both probes passing Jupiter in 1979 and Saturn in 1980–1981. Voyager 2 then went on to make close approaches to Uranus in 1986 and Neptune in 1989. The Voyager probes are now far beyond Pluto's orbit, and astronomers anticipate that they will encounter the heliopause which defines the outer edge of the solar system in the next few years.

Pluto remains the only planet not having been visited by a man-made spacecraft, though that will change with the successful launch of the New Horizons spacecraft on 19 January 2006. This unmanned mission is scheduled to fly by Pluto in July 2015 and then make an extensive study of as many Kuiper Belt objects as it can.

Through these unmanned missions, humans have been able to get close-up photographs of most of the planets and, in the case of landers, perform tests of their soils and atmospheres.

[edit] مُکُ گرھن جون خاصيتون

گرھياتي مدارن جي پيمائش
(ملين ڪلوميٽر)
ھر رنگين پٽي جو ترو ۽ سرو، ترتيبوار، گرھھ جو سج کان گھٽانگھٽ فاصلو ۽ وڌانوڌ فاصلو ظاھر ڪن ٿا .

Plot of equatorial diameter versus semi-major axis for the سج, Mercury, Venus، ڌرتي، مريخ، Jupiter, Saturn, Uranus, Neptune, and Pluto. Vertical pixels are in units of equatorial diameters of Pluto, and horizontal pixels are in units of (4 * semi-major axis of Mercury).

ھيٺ ڏنل سموريون ماپُون ڌرتيءَ جي نسبت سان ڏنل آھن:

Of the other objects، Ganymede has the گھڻي کان گھڻو مايو، 2% that of the ڌرتي.

وڌيڪَ تفصيلي جدول لاءِ ڏسندا: اسان جي شمسي سرشتي جي گرھن جِي جدول

[edit] Attributes of the largest minor planets

The largest minor planets (also known as planetoids) are smoothly rounded, like major planets, because their gravity overcomes material strength that keeps smaller bodies in non-spherical shapes. Before the discovery of 2060 Chiron and the trans-Neptunian objects, the term "minor planet" was a synonym for asteroid, but many people now prefer to restrict the use of "asteroid" to refer to rocky bodies of the inner solar system. Most trans-Neptunian objects are icy, like پڇڙ تارا, although those we can detect at that distance are much larger than comets.

Several asteroids, in the strict sense, are large enough to be spherical. The largest known trans-Neptunian objects are much larger than the large asteroids. (قدرتي اپگرھھ of major planets also range smoothly from small non-spherical objects to large spherical ones, and the largest are larger than 1 Ceres, the largest asteroid).

ھيٺ ڏنل سموريون ماپُون ڌرتيءَ جي نسبت سان ڏنل آھن:

[edit] ٻيون حقيقتون

The total پکيڙَ of the شمسي سرشتي جا objects that have solid surfaces ۽ a قطر greater than 1 km is approximately 1.7×10⁹ km² —about 11 times the area of the Earth's land masses.

It has been suggested that the Sun may be part of a binary star system, with a distant companion named Nemesis. Nemesis was proposed to explain some timing regularities of the great extinctions of life on Earth. The hypothesis says that Nemesis creates periodical perturbations in the Oort cloud of comets surrounding the solar system, causing a "comet shower". Some of them hit ڌرتي, causing destruction of life. This hypothesis is no longer taken seriously by most scientists, mostly because infrared surveys failed to spot any such object, which should have been very conspicuous at those wavelengths.

The concept of the tenth planet has ڪثرتاً been explored in سائنسي افسانو works and conspiracy theories (پڻ ڏسندا Planet X, and hypothetical planet).

[edit] پڻ ڏسندا

Template:Wikibookspar

• Astronomical symbols
• Definition of planet
• Geological features of the Solar System
• Laws of Kepler
• Category:Lists of Solar system objects
• Numerical model of solar system
• Origin of life
• Planetary system
• Planetary nomenclature
• Stellar system
• Table of planetary attributes
• Timeline of discovery of Solar System planets and their natural satellites
• Timeline of solar system astronomy
• Geocentric model
• Titius-Bode law
• Zodiacal light
• Solar system in astrology
• Astrological age
• solar system model

[edit] خارجي ڳنڍڻا

Wikimedia Commons has media related to:

شمسي سرشتو

• NASA's Solar System Exploration site
• [5] A site mentioning some records for the Solar System
• NASA's Solar System Simulator
• NASA/JPL Solar System main page
• Astronomical Enigma Mathematical Order in the orbits of the solar system.
• Solarviews
• Celestia Free 3D realtime space-simulation (OpenGL)
• The Nine Planets Comprehensive solar system site by Bill Arnett
• Planetary data
• Stars and Habitable Planets
• Solar System An interactive planets animation (145 zoom steps and time effects)
• Timeline of solar system exploration
• mirror matter planets and other mirror objects in the solar system?
• The Virtual Solar System, including a scale model of the system

Template:Wikinews

• Tenth planet discovered in outer solar system - NewScientistSpace.com
• Astronomers Discover "10ھون گرھھ لڌو ويو" - آسمان ۽ ڏورويک article
• Tenth Planet Discovered - Astronomy Magazine article
• LARGER THAN PLUTO! 10th Planet Discovered? - Planetary Society
• Tenth planet found! - spaceflightnow.com
• Object Bigger than Pluto Discovered, Called 10th Planet - space.com
• Astronomers detect 'ڏھون گرھھ' - BBC News
• You Call That a Planet? How astronomers decide whether a celestial body measures up. - Slate.com
• 'Planet Xena' has a sidekick: Gabrielle - edition.cnn.com
• Sky and Telescope article on the moon of Template:Mp and the diameter estimate
• The Solar System presented by Utah Skies