History UsefulNotes / TheSolarSystem

->''"'''Mercury''' was near the sun so Janet dropped by – but the mercury on Mercury was much too high.\\
So Janet went to '''Venus''', but on Venus she found: she couldn't see a thing for all the clouds around.\\
'''Earth''' looked exciting, Kind of green and inviting, So Janet thought she'd give it a go. But the creatures on that planet looked so very weird to Janet. She didn't even stop to say 'hello'.\\
'''Mars''' is red, And '''Jupiter''''s big. '''Saturn''' shows off its rings. '''Uranus''' is built on a funny tilt, And '''Neptune''' is its twin.\\
'''Pluto''', little Pluto is the farthest planet from the sun"''

* UsefulNotes/TheSun (popularly formally named in ScienceFiction as '''Sol'''): The star of the show, literally and figuratively. About 99.9% of all the mass in the Solar system is in the sun. Our Sun is a wonderfully stable one, unusually so even for a G-type, which is beneficial for us. Other stars big and small often emit dangerous-to-life x-ray flares. She has the odd sunspot here and there too, and thank goodness; last time our Sun didn't, we experienced an ice age. Rather than red dwarfs, which shine out mostly infrared light, she emits a lot of light in the visible spectrum, [[ThePowerOfTheSun which is just great for photosynthesising plants]]. She does emit ultraviolet radiation too, [[EmbarrassinglyPainfulSunburn so put on that sunblock before you step outside]]. Sadly, all good things must come to an end. The Sun is already 4.6 billion years old, and when it uses up too much of its Hydrogen reserves, it'll get hotter and hotter, eventually becoming a humongous Red Giant that'll no doubt swallow up Earth and the other inner planets.

* UsefulNotes/{{Mars}}: Albedo features identified in the 19th century led to manic speculation about the potential presence of life. Today we know it's not very lively, but that doesn't make it any less interesting. It's still a favorite for space exploration, with a handful of unmanned probes sent there every two years. There are currently five working orbiters around it (''2001 Mars Odyssey'', ''Mars Express'', ''Mars Reconnaissance Orbiter'', ''[=ExoMars=] Trace Gas Orbiter'', ''MAVEN'',''Hope'', and ''Tianwen 1''), [[note]]Respectively sent by UsefulNotes/{{NASA}}, UsefulNotes/{{ESA}}, NASA, Russia, NASA, the United Arab Emirates, and China [[/note]] and two working landers on it (''Perseverence'' and ''Curiosity'').

** [[http://en.wikipedia.org/wiki/Rings_of_Saturn The Rings of Saturn]]

** UsefulNotes/TheMoonsOfNeptune (Greek deities associated with water)

* UsefulNotes/TheSun (popularly formally named in ScienceFiction as '''Sol'''): The star of the show, literally and figuratively. About 99.9% of all the mass in the Solar system is in the sun. Our Sun is a wonderfully stable one, unusually so even for a G-type, which is beneficial for us. Other stars big and small often emit dangerous-to-life x-ray flares. She has the odd sunspot here and there too, and thank goodness; last time our Sun didn't, we experienced an ice age. Rather than red dwarfs, which shine out mostly infrared light, she emits a lot of light in the visible spectrum, [[ThePowerOfTheSun which is just great for photosynthesising plants]]. She does emit ultraviolet radiation too, [[EmbarrassinglyPainfulSunburn so put on that sunblock before you step outside]]. Sadly, all good things must come to an end. The Sun is already 4.6 billion years old, and when it uses up too much of its Hydrogen reserves, it'll get hotter and hotter, eventually becoming a humongous Red Giant that'll no doubt swallow up Earth and the other inner planets.[[/index]]

[[index]]

* UsefulNotes/{{Mars}}: Albedo features identified in the 19th century led to manic speculation about the potential presence of life. Today we know it's not very lively, but that doesn't make it any less interesting. It's still a favorite for space exploration, with a handful of unmanned probes sent there every two years. There are currently five working orbiters around it (''2001 Mars Odyssey'', ''Mars Express'', ''Mars Reconnaissance Orbiter'', ''[=ExoMars=] Trace Gas Orbiter'', ''MAVEN'',''Hope'', and ''Tianwen 1''), [[note]]Respectively sent by UsefulNotes/{{NASA}}, UsefulNotes/{{ESA}}, NASA, Russia, NASA, the United Arab Emirates, and China [[/note]] and two working landers on it (''Perseverence'' and ''Curiosity'').[[/index]]

[[index]]

** [[http://en.wikipedia.org/wiki/Rings_of_Saturn The Rings of Saturn]][[/index]]

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** UsefulNotes/TheMoonsOfNeptune (Greek deities associated with water)[[/index]]

[[index]]

* [[UsefulNotes/DwarfPlanets Pluto]]– Charon[[note]](along with four smaller moons--Nix, Hydra, Kerberos, and Styx)[[/note]][[note]]Charon's status is itself a subject of debate. It is currently classified as Pluto's largest natural satellite, but the IAU has yet to clearly define what a natural satellite is. Some argue that because the Pluto-Charon barycenter lies in the empty space between the two bodies, Charon should be classified as a dwarf planet.[[/note]] [[/index]]

* Eris[[note]](it is accompanied by a single known moon, Dysnomia)[[/note]][[note]]When first discovered, it was nicknamed [[Series/XenaWarriorPrincess Xena]]. No, Dysnomia was never referred to in any official context as "[[{{Sidekick}} Gabrielle]]".[[/note]]

* UsefulNotes/TheSun (popularly formally named in ScienceFiction as '''Sol'''): The star of the show, literally and figuratively. About 99.9% of all the mass in the Solar system is in the sun. Our Sun is a wonderfully stable one, unusually so even for a G-type, which is beneficial for us. Other stars big and small often emit dangerous-to-life x-ray flares. She has the odd sunspot here and there too, and thank goodness; last time our Sun didn't, we experienced an ice age. Rather than red dwarfs, which shine out mostly infrared light, she emits a lot of light in the visible spectrum, [[ThePowerOfTheSun which is just great for photosynthesising plants]]. She does emit ultraviolet radiation too, [[EmbarrassinglyPainfulSunburn so put on that sunblock before you step outside]]. Sadly, all good things must come to an end. The Sun is already 4.6 billion years old, and when it uses up too much of its Hydrogen reserves, it'll get hotter and hotter, eventually becoming a humongous Red Giant that'll no doubt swallow up Earth and the other inner planets. [[/index]]

* UsefulNotes/{{Mars}}: Albedo features identified in the 19th century led to manic speculation about the potential presence of life. Today we know it's not very lively, but that doesn't make it any less interesting. It's still a favorite for space exploration, with a handful of unmanned probes sent there every two years. There are currently five working orbiters around it (''2001 Mars Odyssey'', ''Mars Express'', ''Mars Reconnaissance Orbiter'', ''[=ExoMars=] Trace Gas Orbiter'', ''MAVEN'',''Hope'', and ''Tianwen 1''), [[note]]Respectively sent by UsefulNotes/{{NASA}}, UsefulNotes/{{ESA}}, NASA, Russia, NASA, the United Arab Emirates, and China [[/note]] and two working landers on it (''Perseverence'' and ''Curiosity'').

** [[http://en.wikipedia.org/wiki/Rings_of_Saturn The Rings of Saturn]]

[[index]]

** UsefulNotes/TheMoon (AKA, Luna): Our nearest neighbor, and the only celestial body beyond Earth that has been explored by humans in person (allegedly). It is theorized that the Moon is the left over debris from [[EarthShatteringKaboom a giant impact event]] with a proto-Earth and a Mars-sized object called Theia. Another theory holds that both Theia and the proto-Earth were completely destroyed by the impact, then the debris coalesced to form Earth and the Moon. Or even that they collided ''twice'' before ending up in their current forms. The Moon is a very unusual object (while not the largest moon in the solar system, relative to the size of its planet it's enormous) and the high angular momentum of the Earth-Moon system is even more unusual, and dramatic events were needed to bring it into existence. It's also Tidal Locked, which means it's in a synchronous rotation with Earth, such that the same face is always pointing towards the Earth at all times. This is not as remarkable or unusual as it may appear[[note]]Pluto and Charon experience the same phenomenon[[/note]].

* Last but not least, in January 2016 a group of astronomers have suggested that the eccentric orbits of several large Kuiper Belt Objects (see the Detached Object category of small solar system bodies listed further down) could be explained by the presence of [[https://en.wikipedia.org/wiki/Planet_Nine a ninth planet]] (so-called [[ExactlyWhatItSaysOnTheTin Planet Nine]]), that would be a bit smaller in mass than Neptune or Uranus, two to four times larger than Earth, and that would orbit the Sun in a highly eccentric and inclined orbit that would take many thousands of years to complete never approaching at less than around seven times the Sun-Neptune distance[[note]]At its farthest, Neptune is 30-something AU away from the sun; Planet's Nine's nearest distance to the sun is predicted to be about ''200 AU''[[/note]]. Please note, however, that despite the claims of "a new planet discovered" there's at best just indirect proof of its existence and it's an entirely hypothetical object until it's finally imaged[[note]]Not something that will be easy, mind you, with ''millions'' of stars and galaxies of similar brightness to that planet if it existed at all[[/note]].

** UsefulNotes/TheMoon (AKA, Luna): Our nearest neighbor, and the only celestial body beyond Earth that has been explored by humans in person (allegedly). It is theorized that the Moon is the left over debris from [[EarthShatteringKaboom a giant impact event]] with a proto-Earth and a Mars' sized object called Theia. Another theory holds that both Theia and the proto-Earth were completely destroyed by the impact, then the debris coalesced to form Earth and the Moon. Or even that they collided ''twice'' before ending up in their current forms. The Moon is a very unusual object (while not the largest moon in the solar system, relative to the size of its planet it's enormous) and the high angular momentum of the Earth-Moon system is even more unusual, and dramatic events were needed to bring it into existence. It's also Tidal Locked, which means it's in a synchronous rotation with Earth, such that the same face is always pointing towards the Earth at all times. This is not as remarkable or unusual as it may appear[[note]]Pluto and Charon experience the same phenomenon[[/note]].

** More seriously, Earth is the 6th most massive solar system object, the largest of the Rocky planets, and the most dense object. It is one of two worlds (or possibly three, with supersalty water on Mars) with liquids on the surface, forming rivers, lakes, and such (The other is Saturn's moon Titan, with methane and ethane as the surface liquids), the only one with life (that we know of), and the only one with plate tectonics. The atmosphere is unique in having a large proportion as free oxygen, which in addition to supporting most life, changes the structure in a number of subtle ways compared to other planets. Earth also generates a magnetic field, unlike Venus and Mars, that is much stronger than that of Mercury but weaker than that of the gas giants. Our world used to have a similar atmosphere with its "twin" Venus, but lost it in the giant impact event.

The things you can find in our star system. Generally speaking, it consists of a central star, four Earth-type planets, four gas giants, and a large amount of smaller objects, including dwarf planets, moons, asteroids, comets and space junk, mostly clustered in rings around the Sun or other planets.

* UsefulNotes/TheSun (Popularly formally named in ScienceFiction as '''Sol'''): The star of the show, literally and figuratively. About 99.9% of all the mass in the Solar system is in the sun. Our Sun is a wonderfully stable one, unusually so even for a G-type, which is beneficial for us. Other stars big and small often emit dangerous-to-life x-ray flares. She has the odd sunspot here and there too, and thank goodness; last time our Sun didn't, we experienced an ice age. Rather than red dwarfs, which shine out mostly infrared light, she emits a lot of light in the visible spectrum, [[ThePowerOfTheSun which is just great for photosynthesising plants]]. She does emit ultraviolet radiation too, [[EmbarrassinglyPainfulSunburn so put on that sunblock before you step outside]]. Sadly, all good things must come to an end. The Sun is already 4.6 billion years old, and when it uses up too much of its Hydrogen reserves, it'll get hotter and hotter, eventually becoming a humongous Red Giant that'll no doubt swallow up Earth and the other inner planets. [[/index]]

* UsefulNotes/TheSun (Popularly formally named in ScienceFiction as '''Sol'''): The star of the show, literally and figuratively. About 99.9% of all the mass in the Solar system is in the sun. Our Sun is a wonderfully stable one, unusually so even for a G-type, which is beneficial for us. Other stars big and small often emit dangerous-to-life x-ray flares. She has the odd sunspot here and there too, and thank goodness; last time our Sun didn't, we experienced an ice age. Rather than red dwarfs, which shine out mostly infrared light, she emits a lot of light in the visible spectrum, [[ThePowerOfTheSun which is just great for photosynthesising plants]]. She does emit ultraviolet radiation too, [[EmbarrassinglyPainfulSunburn so put on that sunblock before you step outside]]. Sadly, all good things must come to an end. The Sun is already 4.6 billion years old, and when it uses up too much of its Hydrogen reserves, it'll get hotter and hotter, until becoming a humongous Red Giant that'll no doubt swallow up the inner planets along with Earth. [[/index]]

* UsefulNotes/TheSun (Popularly formally named in ScienceFiction as '''Sol'''): The star of the show, literally and figuratively. About 99.9% of all the mass in the Solar system is in the sun. Our Sun is a wonderfully stable one, unusually so even for a G-type, which is beneficial for us. Other stars big and small often emit dangerous-to-life x-ray flares. She has the odd sunspot here and there too, and thank goodness, last time our Sun didn't, we experienced an ice age. Rather than red dwarfs, that shine out mostly infrared light, she emits a lot of light on the visible spectrum, [[ThePowerOfTheSun which is just great for photosynthesising plants]]. She does emit ultraviolet radiation too, [[EmbarrassinglyPainfulSunburn so put on that sunblock before you step outside]]. Sadly, all good things must come to an end. The Sun is already 4.6 billion years old, and when it uses up too much of its Hydrogen reserves, it'll get hotter and hotter, until becoming a humongous Red Giant that'll no doubt swallow up the inner planets along with Earth. [[/index]]

* UsefulNotes/{{Mars}}: Albedo features identified in the 19th century led to manic speculation about the potential presence of life. Today we know it's not very lively, but that doesn't make it any less interesting. It's still a favorite for space exploration, with a handful of unmanned probes sent there every two years. There are currently five working orbiters around it (''2001 Mars Odyssey'', ''Mars Express'', ''Mars Reconnaissance Orbiter'', ''ExoMars Trace Gas Orbiter'', ''MAVEN'',''Hope'', and ''Tianwen 1''), [[note]]Respectively sent by UsefulNotes/{{NASA}}, UsefulNotes/{{ESA}}, NASA, Russia, NASA, the United Arab Emirates, and China [[/note]] and two working landers on it (''Perseverence'' and ''Curiosity'').

* UsefulNotes/{{Mars}}: Albedo features identified in the 19th century led to manic speculation about the potential presence of life. Today we know it's not very lively, but that doesn't make it any less interesting. It's still a favorite for space exploration, with a handful of unmanned probes sent there every two years. There are currently five working orbiters around it (''2001 Mars Odyssey'', ''Mars Express'', ''Mars Reconnaissance Orbiter'', ''MAVEN'', and ''Mangalyaan''), [[note]]Respectively sent by UsefulNotes/{{NASA}}, UsefulNotes/{{ESA}}, NASA, NASA, and ISRO (the last being India, for those not up on their space agencies)[[/note]] and two working landers on it (''[=InSight=]'' and ''Curiosity'').

[[caption-width-right:350:[[MyFriendsAndZoidberg Ignore Pluto.]] [[PlutoIsExpendable It's not a planet anymore.]][softreturn]Also, [[YouCannotGraspTheTrueForm definitely not to scale]].]]

Despite years and years of ScienceFiction stories about planets around other suns, we actually lacked any real scientific proof of them until the early 1990's when exoplanets were first detected by their wobble on their parent star. Until then, it was quite possible that our solar system was simply a fluke. For example, one theory on the formation of our solar system, "Tidal Theory" - 1917, was that a passing star came close to our sun, drawing a filament of solar matter out of it which coalesced into the planets. Website/{{Wikipedia}} has a page on those theories [[https://en.wikipedia.org/wiki/History_of_Solar_System_formation_and_evolution_hypotheses here]] if you are interested.

As for the future, things will not change very much for the Solar System ''as a whole'' during the next five billion years[[note]]Some calculations simulations give a very small probability within that timeframe of either Mercury going haywire and being ejected of the Solar Sytem if it does not crash before into either Venus or Earth, or Mars colliding with Earth. Sleep well, it will ''not'' happen tomorrow. [[ParanoiaFuel We think]][[/note]]. Sure, the orbits of some moons such as Mars' Phobos or Neptune's Triton will decay and the latter will produce both a ''hell'' of a meteor shower and a splendid ring system around its planet, the occasional asteroid/impact here and there will happen, the occasional star passing too close and shaking the Oort Cloud sending comets to the inner Solar System, [[BreadEggsMilkSquick and the Earth becoming unhabitable]] because of a Sun that is brightening with time as described above but if we could see the Solar System by then it is expected we'd see something very similar to the current one[[note]]OK, the Andromeda Galaxy and the Milky Way are expected to [[FusionDance merge]] around those ages and the Sun will end up on the outskirts of the newly-formed galaxy, if not thrown out to intergalactic space (it will come back much later, though), but unless we've ''very'' bad luck the collision will not affect us[[/note]].
Five billion years was not chosen at random for the fate of our Solar System is tightly tied to the one of its most massive body: the Sun. By that epoch it will have run out of hydrogen at its center and things will become interesting, so let's fast forward to the year [[TimeAbyss 7,590,000,000 AD]][[note]]After core hydrogen exhaustion, the Sun will take its time to become a red giant -one and a half billion years still as something not very different of our current daystar - but more luminous - followed by seven hundred million years as a cooler and larger, but not more luminous subgiant star, and finally roughly six hundred million years to go full red giant. Stellar evolution takes usually its time - and remember that these are theoretical calculations, so while the basic picture will be more or less the same given numbers may somewhat change as ScienceMarchesOn.[[/note]]. In that year our familiar Sun will be in [[OneWingedAngel full red giant-mode]]: a bloated and distorted star with a surface temperature having dropped to half of what it has in our epoch, thousands of times more luminous and more than two hundred times larger than our daystar[[note]]Why if there's no more hydrogen in the core?. Hydrogen is intensely fusing instead around the small, hydrogen-exhausted, dense core of inert helium, that as it contracted caused first the hydrogen surrounding it to start fusing, and later as temperatures increased because of said contraction to fuse more and more intensely. At least, since the process will take so much time it has been calculated that temperatures will be Earth-like (the so-called "habitable zone") for some hundred million years in places as Mars or further out (Jupiter). Perhaps life will manage to appear there, even if it had little time to evolve.[[/note]], and so big that has lost more than a quarter of its mass carried away by strong solar winds, something that has caused the planet's orbits to wide, but not enough to avoid searing hot temperatures or worse[[note]]For the details: Mercury and Venus are history, having been engulfed millions of years before by the expanding Sun but not before having been roasted to Hell and back -and Venus having lost its atmosphere (poor Venus, she cannot catch a break)-. Earth, with no atmosphere to speak of and [[DeathWorld with a surface temperature of more than one thousand five hundred degrees Celsius]], is a LethalLavaLand precariously clinging to its orbit under an angry Sun that fills a whole lot of its sky and is very likely doomed to suffer the same fate of the two innermost planets. Mars is another LethalLavaLand that (we think) will survive the ordeal. Of the giant planets, temperatures will vary between the searing hot ones of Jupiter (higher than those at Mercury, but at least it could manage to accrete some (it will certainly ''not'' capture enough to be significant, much less to become a star) of the matter expelled by the Sun) and the rather Earth-like ones of Neptune, with their icy moons looking like huge comets evaporating under the intense sunlight, maybe up to being totally vaporized in the cases of those composed almost of ice as the moons of Saturn, and probably after their surfaces have melted as temperature screamed upwards and had liquid oceans for a time, said water vaporized giving hellish, worse than Venus-like conditions, to the rocky surfaces below all that ice in some cases as Europa, Ganymede, or Titan before it was lost to space. The smallest bodies -asteroids and comets-, even as far as the Kuiper Belt, not only have to contend with the intense heat but also with the mess caused to their orbits by the mass loss of the dying Sun, meaning that some of them will end being ejected out of the Solar System and others will either crash with the remaining planets or into the Sun[[/note]]. It will also be the time when the Sun will suffer a dramatic transformation: the dense, inert helium core will ignite and will produce for a few seconds ''as much energy as an entire galaxy'' in what astronomers know as the "helium flash". While this looks like a supernova, that energy will actually just be used to re-expand the core and nothing of that will be seen at its surface -in fact, with the Sun's innards expanding to fuse helium stably it will release less energy and will collapse back to a much smaller and less luminous star a bit more hot than its red giant past (somewhat more than four thousand degrees Celsius), but still quite luminous (forty-fifty times more) and large (ten times larger) compared with its past long-lived incarnation requiring several thousand years to become that[[note]]Whatever remains of the inner Solar System -perhaps only Mars- will be hotter than Mercury. Farther away, Jupiter will enjoy Earth-like temperatures and even farther our things will freeze again. Meanwhile, asteroids and the like will keep their dance of death[[/note]]. Unfortunately for the Sun helium, fusing to produce carbon and oxygen, is a worse fuel than hydrogen and even if helium burning its supported by some hydrogen fusing around the core our star will run out of it in just a hundred million years and then the Sun will face a similar crisis to the one it faced when it ran out of hydrogen there. Only this time said crisis will be fatal.
As happened with hydrogen before, helium will begin to fuse around an inert, contracting, core of carbon and oxygen[[note]]In vain; the Sun is too small to reach the temperatures and densities to fuse carbon[[/note]]. Further out, hydrogen will keep fusing to helium and as the core contracts it will "squeeze" those two burning shells causing them to fuse with more force. The result is that the Sun will become again -in just twenty million years compared to the considerably longer time (more than two billion years, see above) it needed to expand for the first time- a huge and luminous red giant suffering even stronger mass loss but, as helium burning under those extreme conditions is ''highly'' sensitive to the temperature[[note]]It scales as the temperature ''to the fortieth power''. Guess how nasty would be even small variations[[/note]], [[ClippedWingAngel an unstable one]]. Each hundred thousand years, the Sun will convulse suffering a pulse caused by a runaway helium shell burning ignition that will increase its luminosity as well as it radius just to contract when it stops and having things starting again. Those violent pulses will increase even more the already heavy mass loss as mentioned before, and by the fourth one all that will remain of the Sun will be the ''extremely'' hot -one hundred thousand degrees Celsius- and dense, as it has contracted to the size of the Earth, carbon-oxygen core half as massive as the Sun is now: a white dwarf. If the Sun is luminous enough, its ultraviolet radiation will cause the matter that ejected before to fluoresce as a beautiful [[https://en.wikipedia.org/wiki/Planetary_nebula planetary nebula]], that will however be short-lived as a few thousand years later both the gases will be rarefied and far away enough and the white dwarf's ultraviolet radiation will fade away as it begins to cool to stop shining. All that will remain to the dead white dwarf Sun is to keep cooling over [[TimeAbyss many billions of years]] until it will fade into oblivion as a black dwarf -or, if you prefer it, as a big and dense diamond as all those carbon will crystalize during said cooling.[[note]]No, we have not forgotten the planets and all that other stuff. Things will be as during the previous red giant stage, but this time ''harder'', as the Sun's convulsions will cause severe variations of temperature on them and will be pummeled by the matter expelled in the pulses. The worst, however, will come because of that severe mass drain with the Solar System becoming an even more of a mess with many small bodies at least having their orbits more or less dislocated with all that means -collisions either among them or the Sun, things being flung out, etc. Said mess is expected to continue into the planetary nebula and white dwarf stages (it's conceivable its UV flux during the planetary nebula phase will be more or less nasty for the orbiting bodies), and whatever survives the ordeal -odds are that the four largest planets at the very least- will see the black, incredibly cold, veil of an endless night being put over it. The end... or is it?. [[TimeAbyss Time will keep ticking on]], and the very occasional star passing too close will strip the dead Sun of more or less of its remaining retinue of orbiting bodies. It has been estimated that in a ''quadrillion'' (ten to the fifteenth) years, it will have lost all of them.[[/note]]