Scattered_disc - Wikiparency

# Scattered disc  **Microsim — three.js (Wikitube framework):** *The scattered disc in the Solar System explorer* <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/solar/Solar_System.html?obj=scattered&embed=1" data-title="The scattered disc in the Solar System explorer"></div> *The Solar System explorer locked on this article's state (`?obj=scattered`); every object and population of the [[PORTAL_Solar_System|Solar System portal]] has its own state in the same scene.*  *Try: under show, choose small bodies to leave the scattered disc's sampled points on their own, and scroll out until you see them stretch from the Kuiper belt's edge to around 500 AU; drag to an edge-on view to see how much thicker the disc is than the plane of the planets; press l to label the bodies and find Eris and Gonggong, whose orbits are drawn from real elements.* The **scattered disc** (or scattered disk) is a sparsely populated region of the outer Solar System occupied by icy [[Small_Solar_System_body|small bodies]] on eccentric, often steeply inclined orbits, a subset of the [[Trans-Neptunian_object|trans-Neptunian objects]].[^gomes2008][^levison2007] Scattered-disc objects (SDOs) have perihelia near or beyond [[Neptune]]'s orbit, around 30–35 AU, but their orbits can reach well past 100 AU, with eccentricities up to about 0.8 and inclinations up to about 40°; which places them among the most remote and frigid bodies yet catalogued around the Sun.[^trujillo2000][^jewitt-skbo] Their orbits are thought to be the product of gravitational "scattering" by the giant planets, and Neptune still perturbs them.[^duncan1997][^morbidelli2004] The inner part of the disc overlaps the [[Kuiper_belt|Kuiper belt]], but the disc reaches far greater distances from the [[Sun]] and strays much higher above and below the [[Ecliptic|ecliptic]].[^morbidelli2005] Because its orbits are unstable over long times, the scattered disc is considered the main source of the Jupiter-family comets, with the [[Centaur_(small_Solar_System_body)|centaurs]] as the intermediate stage between the disc and the inner Solar System; many bodies of the [[Oort_cloud|Oort cloud]] may also have passed through it.[^horner2004][^gladman2005] Its largest known member is [[Eris_(dwarf_planet)|Eris]].[^brown2005] The explorer at the top of this page opens on the scattered disc: its points, with perihelia inside the Kuiper belt and orbits reaching out to about 500 AU, are ILLUSTRATIVE samples of the population's shape, not catalogued objects, while Eris and [[Gonggong_(dwarf_planet)|Gonggong]] are real bodies drawn from JPL's Small-Body Database.[^sbdb] ## Discovery Until the 1980s, new Solar System bodies were found photographically, by exposing and developing pairs of plates and comparing them by eye in a blink comparator to catch anything that had moved. Electronic CCD detectors, which record most of the light that falls on them where film records only a small fraction, and which let the comparison be done on a computer screen, made faint searches far more productive. More than a thousand trans-Neptunian objects were found between 1992 and 2006.[^sheppard2005] The first object recognised as a member of a scattered population was 1996 TL66, found in 1996 by astronomers working at Mauna Kea in Hawaii. With a semi-major axis of about 85 AU, an eccentricity near 0.6 and a perihelion near 35 AU,[^sbdb] it did not fit any of the Kuiper belt classes then known, and Luu, Marsden and Jewitt described it in 1997 as "a new dynamical class of object in the outer Solar System".[^luu1997] The same survey found three more such bodies in 1999.[^jewitt-skbo][^trujillo2000] The first object now classed as scattered to have been discovered was 1995 TL8, found by Spacewatch in 1995.[^schmadel2012] By 2011 more than 200 SDOs were catalogued.[^mpc-list] Among them are Eris, found in 2005 by Brown, Trujillo and Rabinowitz; Gonggong, found in 2007 by Schwamb, Brown and Rabinowitz; and [[Sedna_(dwarf_planet)|Sedna]], found in 2003 and sometimes listed with them.[^brown2005][^schwamb2008][^mpc-disc] The Kuiper belt and the scattered disc may hold comparable numbers of objects, but the scattered bodies spend most of their time far from the Sun, where they are too faint to detect, so far fewer have been seen.[^levison2007] ## Subdivisions of trans-Neptunian space Astronomers usually sort the bodies found beyond Neptune into two groups: the Kuiper belt and the scattered disc. The Oort cloud, a more remote reservoir, is inferred from the orbits of long-period comets but has not been observed directly.[^morbidelli2004][^morbidelli2005] Some researchers also recognise an intermediate zone, lying outside the scattered disc but short of the inner Oort cloud, where [[Detached_object|detached objects]] orbit.[^gomes2008] ### Scattered disc versus Kuiper belt The Kuiper belt is a thick, doughnut-shaped region roughly 30–50 AU from the Sun.[^desanctis2001] It holds two main populations: the [[Classical_Kuiper_belt_object|classical objects]], on orbits that Neptune does not disturb, and the [[Resonant_trans-Neptunian_object|resonant objects]], locked by Neptune into exact period ratios such as 2:3, the [[Plutino|plutinos]] led by [[Pluto]], and 1:2, the "twotinos". A resonance keeps such a body from ever meeting Neptune at close range, so it can survive in a region that Neptune would otherwise have cleared over the age of the Solar System.[^levison2007] Scattered-disc objects, in contrast, come within Neptune's reach at perihelion, near 30 AU, while their aphelia lie many times farther out, so the planet can still change their orbits.[^gomes2008][^morbidelli2007] The centaurs, icy bodies whose orbits lie between those of [[Jupiter]] and Neptune, may be nothing more than SDOs that Neptune has thrown inward, and the Minor Planet Center lists centaurs and SDOs together; objects such as 1999 TD10 straddle the boundary.[^horner2003][^mpc-list][^silber1999] The Minor Planet Center still separates the stable Kuiper belt from the scattered objects, but many astronomers see the disc as an outer extension of the belt, and the name "scattered Kuiper belt object" is also used.[^mpc-list][^jewitt-bigkbo] Morbidelli and Brown proposed that SDOs be defined as bodies moved in semi-major axis by close or distant encounters with Neptune. Because a resonant body can switch between scattering and non-scattering phases many times over the age of the Solar System, they chose to define regions rather than objects: the scattered disc is the part of orbital space that can be reached by bodies that have come within Neptune's [[Hill_sphere|Hill sphere]], and the Kuiper belt is the rest of the region beyond 30 AU.[^morbidelli2004] ### Detached objects The Minor Planet Center lists Sedna as a scattered-disc object, but its discoverer Michael Brown has argued that, with a perihelion of 76 AU, it is too far from the planets to feel their pull and belongs to the inner Oort cloud.[^mpc-list][^brown-sedna] On that reasoning, bodies with perihelia beyond about 40 AU fall outside the scattered disc.[^lykawka2007] Sedna is not alone: 2000 CR105, found before it, and 474640 Alicanto also have perihelia too distant for Neptune to affect, which led to talk of an "extended scattered disc".[^gladman-cr105] Such bodies are now usually called detached objects, and the most extreme of them [[Extreme_trans-Neptunian_object|extreme trans-Neptunian objects]].[^jewitt2006][^gomes2006] No sharp boundary separates the two regions.[^lykawka2007] In the definition used by Gomes and colleagues, an SDO needs only a strongly elongated orbit, a perihelion outside Neptune's orbit and a semi-major axis larger than that of the 1:2 resonance, so the detached bodies count as SDOs too.[^gomes2008] Because Neptune cannot raise perihelia so far, other agents have been proposed for the detached orbits: a star passing close to the young Sun, an undiscovered planet-sized body far from the Sun, or capture of the bodies from another star.[^morbidelli2004b][^pfalzner2018][^gomes2006][^jilkova2015] Two formal classifications are in use. The Deep Ecliptic Survey of Elliot and colleagues (2005) divides scattered bodies into "scattered-near" objects, non-resonant with a Tisserand parameter relative to Neptune below 3, and "scattered-extended" objects, the detached ones, with a Tisserand parameter above 3 and a time-averaged eccentricity above 0.2.[^elliot2005] Gladman, Marsden and Van Laerhoven (2008) instead integrate each orbit for 10 million years: a non-resonant body with a semi-major axis up to 2,000 AU whose semi-major axis wanders by 1.5 AU or more is a "scattering" object, and a stable one with an eccentricity above 0.24 is detached.[^gladman2008] ## Orbits The scattered disc is a dynamic environment. Because Neptune still perturbs them, SDOs are always at risk of being pushed outward towards the Oort cloud or inward among the centaurs and eventually into the Jupiter family of comets; Gladman and colleagues therefore prefer the term "scattering disc".[^levison2007][^gladman2008] SDOs typically have semi-major axes beyond 50 AU with moderate to high eccentricities, and perihelia near 30 AU, close enough for Neptune's gravity to act on them.[^trujillo2000][^jewitt-skbo] A worked example shows how elongated these orbits are. For a body with a perihelion of 35 AU and an eccentricity of 0.8, the semi-major axis is 35 / 0.2 = 175 AU and the aphelion 315 AU; by [[Kepler's_laws_of_planetary_motion|Kepler's third law]] it takes about 2,300 years to go round and spends nine-tenths of that time beyond 100 AU (derived). Eris, with a perihelion of 38.2 AU and an aphelion of 97.7 AU, is a relatively moderate case, and Gonggong reaches about 101 AU.[^sbdb] The contrast with the Kuiper belt is also one of shape. Many classical Kuiper belt objects follow nearly circular, low-inclination orbits, whereas very few SDOs lie close to the ecliptic, and their inclinations reach about 40°.[^levison2007][^bertoldi2006] Although the scattering is random, SDOs can be caught temporarily in weak, high-order resonances with Neptune; possible examples include the 1:3, 2:7, 3:11, 5:22 and 4:79 ratios.[^gomes2008] The explorer's sampled points follow this pattern, with perihelia clustered just beyond Neptune and aphelia spread far outward, but their number and positions are ILLUSTRATIVE; only the orbits of named bodies such as Eris and Gonggong come from catalogued elements.[^sbdb] ## Formation Every proposed account of how the Kuiper belt and scattered disc came to be still fails to reproduce some of what is observed.[^morbidelli2004] In current models, the scattered disc formed when bodies of the primordial trans-Neptunian disc were thrown onto eccentric, inclined orbits by gravitational encounters with Neptune and the other outer planets.[^duncan1997] How long this took remains uncertain. In one view the process has continued for the whole age of the Solar System: weak resonances within the Kuiper belt, or the edges of strong ones, slowly destabilise orbits on timescales of millions of years, with the 4:7 resonance an especially leaky example, and close passages by massive bodies or collisions also feed objects into scattering orbits.[^levison1997][^gomes2008] The other view places most of the scattering early, during the migration of the giant planets. Too little material existed beyond [[Saturn]] for [[Uranus]] and Neptune to have grown where they now orbit; they probably formed closer in and were moved outward by exchanging [[Angular_momentum|angular momentum]] with the planetesimals they scattered.[^thommes2002][^hahn2005] In the [[Nice_model|Nice model]], when Jupiter and Saturn crossed their 1:2 mean-motion resonance, their combined pull destabilised Uranus and Neptune and sent Neptune into the primordial disc of icy bodies, scattering many onto large, eccentric orbits.[^hansen2005][^duncan1997] Hahn and Malhotra's simulations suggest that 90 percent or more of scattered objects may have been placed on their eccentric orbits by Neptune's sweeping resonances during this migration, so that the scattered disc "might not be so scattered".[^hahn2005] ## Composition Like other trans-Neptunian objects, scattered bodies have low densities and consist largely of frozen volatiles, such as [[Water|water]] ice and methane, mixed with rock.[^tegler2007] Spectra of the largest bodies show similar compounds: both Pluto and Eris, for example, display methane ice.[^brown2005] Astronomers originally expected all trans-Neptunian objects to share a red colour, since they were thought to have formed in one region and to have undergone the same processing: methane on their surfaces, broken down by solar ultraviolet light into dark, reddish tholins, should absorb blue light.[^tegler2007] Most classical objects are indeed red, but scattered objects are not; they tend to look white or grey.[^tegler2007] One explanation is that impacts have exposed paler subsurface ice; another is a compositional gradient with distance from the Sun, analogous to the difference between the terrestrial and giant planets.[^tegler2007] For Eris, Brown and colleagues suggested that the pale colour arises because, at its present great distance, its thin methane atmosphere has frozen out over the entire surface as a bright layer of fresh ice, whereas on Pluto, closer to the Sun, methane freezes only onto the colder, brighter regions and leaves tholin-darkened ground exposed.[^brown2005] ## Comets The Kuiper belt was at first taken to be where the ecliptic comets come from, the short-period comets whose orbits lie near the plane of the planets. Studies after 1992 showed, however, that most Kuiper belt orbits are stable over the age of the Solar System, and that the less stable scattered disc is the more likely source.[^gladman2005][^duncan1997] Comets are divided broadly into long-period comets, thought to come from the Oort cloud, and short-period comets. The short-period comets comprise two main groups: the Jupiter-family comets and the Halley-type comets, named after [[Halley's_Comet|Halley's Comet]].[^levison2007] The Halley-type comets are thought to come from the Oort cloud, drawn inward by the giant planets, whereas the Jupiter-family comets are thought to come from the scattered disc.[^jewitt2002][^morbidelli2007] The centaurs are the dynamical intermediate stage: a scattered-disc body perturbed inward by Neptune passes among the giant planets as a centaur until [[Jupiter]] captures it onto a short-period [[Comet|comet]] orbit.[^horner2003][^horner2004] The link is not straightforward in every respect. Many centaurs, like many SDOs, are red or neutral in colour, but the nuclei of Jupiter-family comets are bluer, which points to a physical or chemical change on the way inward. One explanation is that as a comet approaches the Sun, its activity buries or removes the old reddened crust under fresh material from below.[^jewitt2002] ## See also - [[Kuiper_belt]] · [[Trans-Neptunian_object]] - [[Detached_object]] · [[Extreme_trans-Neptunian_object]] - [[Centaur_(small_Solar_System_body)]] · [[Comet]] - [[Oort_cloud]] - [[Eris_(dwarf_planet)]] · [[Gonggong_(dwarf_planet)]] · [[Sedna_(dwarf_planet)]] - [[PORTAL_Solar_System|Solar System portal]] ## Notes Derived numbers use Kepler's third law in solar units (P in years = a^1.5 with a in AU): for q = 35 AU and e = 0.8, a = q / (1 − e) = 175 AU, Q = a(1 + e) = 315 AU and P = 175^1.5 ≈ 2,300 years; the fraction of the orbit spent beyond 100 AU follows from Kepler's equation with r = a(1 − e cos E): r = 100 AU at cos E ≈ 0.536, E ≈ 1.005 rad, and the mean anomaly M = E − e sin E ≈ 0.330 rad, so the body is inside 100 AU for 2 × 0.330 / 2π ≈ 10.5 percent of the period and beyond it for about 89 percent. The 1996 TL66 orbital values are from its JPL Small-Body Database entry. ## References [^sbdb]: JPL Small-Body Database, entries for 136199 Eris, 225088 Gonggong and 1996 TL66 (orbital elements fetched 2026-09-18). https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html [^gomes2008]: Gomes, R. S.; Fernández, J. A.; Gallardo, T.; Brunini, A. (2008). "The scattered disk: Origins, dynamics, and end states". In *The Solar System Beyond Neptune*. University of Arizona Press. http://www.fisica.edu.uy/~gallardo/scatdisk.pdf [^levison2007]: Levison, H. F.; Donnes, L. (2007). "Comet populations and cometary dynamics". In McFadden, L.-A.; Weissman, P. R.; Johnson, T. V. (eds.), *Encyclopedia of the Solar System* (2nd ed.). Academic Press, pp. 575–588. ISBN 978-0-12-088589-3. [^trujillo2000]: Trujillo, C. A.; Jewitt, D. C.; Luu, J. X. (2000). "Population of the scattered Kuiper belt". *The Astrophysical Journal* 529: L103–L106. https://doi.org/10.1086/312467 [^jewitt-skbo]: Jewitt, D. C. (2009). "Scattered Kuiper belt objects (SKBOs)". Institute for Astronomy. http://www2.ess.ucla.edu/~jewitt/kb/kb-scattered.html [^duncan1997]: Duncan, M. J.; Levison, H. F. (1997). "A disk of scattered icy objects and the origin of Jupiter-family comets". *Science* 276: 1670–1672. https://doi.org/10.1126/science.276.5319.1670 [^morbidelli2004]: Morbidelli, A.; Brown, M. E. (2004). "The Kuiper belt and the primordial evolution of the Solar System". In Festou, M. C.; Keller, H. U.; Weaver, H. A. (eds.), *Comets II*. University of Arizona Press, pp. 175–191. http://www.lpi.usra.edu/books/CometsII/7004.pdf [^morbidelli2005]: Morbidelli, A. (2005). "Origin and dynamical evolution of comets and their reservoirs". arXiv:astro-ph/0512256. https://arxiv.org/abs/astro-ph/0512256 [^horner2004]: Horner, J.; Evans, N. W.; Bailey, M. E. (2004). "Simulations of the population of Centaurs — I. The bulk statistics". *Monthly Notices of the Royal Astronomical Society* 354: 798–810. https://doi.org/10.1111/j.1365-2966.2004.08240.x [^gladman2005]: Gladman, B. (2005). "The Kuiper belt and the solar system's comet disk". *Science* 307: 71–75. https://doi.org/10.1126/science.1100553 [^brown2005]: Brown, M. E.; Trujillo, C. A.; Rabinowitz, D. L. (2005). "Discovery of a planetary-sized object in the scattered Kuiper belt". *The Astrophysical Journal* 635: L97–L100. https://doi.org/10.1086/499336 [^sheppard2005]: Sheppard, S. S. (2006). "Small bodies in the outer Solar System". In *New Horizons in Astronomy: Frank N. Bash Symposium 2005*, ASP Conference Series 352, pp. 3–14. ISBN 1-58381-220-2. http://www.ciw.edu/sheppard/pub/Sheppard06smallbodies.pdf [^luu1997]: Luu, J.; Marsden, B. G.; Jewitt, D.; et al. (1997). "A new dynamical class of object in the outer Solar System". *Nature* 387: 573–575. https://doi.org/10.1038/42413 [^schmadel2012]: Schmadel, L. D. (2012). *Dictionary of Minor Planet Names* (6th ed.). Springer, p. 925 (Appendix 10). ISBN 978-3-642-29717-5. [^mpc-list]: Minor Planet Center (3 January 2011). "List of Centaurs and Scattered-Disk Objects". http://www.minorplanetcenter.org/iau/lists/Centaurs.html [^schwamb2008]: Schwamb, M. E.; Brown, M. E.; Rabinowitz, D.; Marsden, B. G. (2008). "2007 UK126". *Minor Planet Electronic Circular* 2008-D38. Bibcode 2008MPEC....D...38S. [^mpc-disc]: Minor Planet Center. "Discovery circumstances: Numbered minor planets". http://www.minorplanetcenter.org/iau/lists/NumberedMPs.html [^desanctis2001]: De Sanctis, M. C.; Capria, M. T.; Coradini, A. (2001). "Thermal evolution and differentiation of Edgeworth–Kuiper belt objects". *The Astronomical Journal* 121: 2792–2799. https://doi.org/10.1086/320385 [^morbidelli2007]: Morbidelli, A.; Levison, H. F. (2007). "Kuiper-belt objects: Dynamics". In McFadden, L.-A.; Weissman, P. R.; Johnson, T. V. (eds.), *Encyclopedia of the Solar System* (2nd ed.). Academic Press, pp. 589–604. ISBN 978-0-12-088589-3. [^horner2003]: Horner, J.; Evans, N. W.; Bailey, M. E.; Asher, D. J. (2003). "The populations of comet-like bodies in the Solar System". *Monthly Notices of the Royal Astronomical Society* 343: 1057–1066. https://doi.org/10.1046/j.1365-8711.2003.06714.x [^silber1999]: Silber, K. (1999). "New object in Solar System defies categories". *Space.com*. http://www.space.com/scienceastronomy/solarsystem/centaur_disc_991111.html [^jewitt-bigkbo]: Jewitt, D. C. (2008). "The 1000 km scale KBOs". Institute for Astronomy. http://www2.ess.ucla.edu/~jewitt/kb/big_kbo.html [^brown-sedna]: Brown, M. E. "Sedna". California Institute of Technology. http://www.gps.caltech.edu/~mbrown/sedna/ [^lykawka2007]: Lykawka, P. S.; Mukai, T. (2007). "Dynamical classification of trans-Neptunian objects: Probing their origin, evolution, and interrelation". *Icarus* 189: 213–232. https://doi.org/10.1016/j.icarus.2007.01.001 [^gladman-cr105]: Gladman, B. J. "Evidence for an extended scattered disk?". Observatoire de la Côte d'Azur. http://www.obs-nice.fr/gladman/cr105.html [^jewitt2006]: Jewitt, D.; Delsanti, A. (2006). "The Solar System beyond the planets". In *Solar System Update*. Springer-Praxis. ISBN 978-3-540-26056-1. http://www2.ess.ucla.edu/~jewitt/papers/2006/DJ06.pdf [^gomes2006]: Gomes, R. S.; Matese, J. J.; Lissauer, J. J. (2006). "A distant planetary-mass solar companion may have produced distant detached objects". *Icarus* 184: 589–601. https://doi.org/10.1016/j.icarus.2006.05.026 [^morbidelli2004b]: Morbidelli, A.; Levison, H. F. (2004). "Scenarios for the origin of the orbits of the trans-Neptunian objects 2000 CR105 and 2003 VB12 (Sedna)". *The Astronomical Journal* 128: 2564–2576. https://doi.org/10.1086/424617 [^pfalzner2018]: Pfalzner, S.; Bhandare, A.; Vincke, K.; Lacerda, P. (2018). "Outer Solar System possibly shaped by a stellar fly-by". *The Astrophysical Journal* 863: 45. https://doi.org/10.3847/1538-4357/aad23c [^jilkova2015]: Jílková, L.; Portegies Zwart, S.; Pijloo, T.; Hammer, M. (2015). "How Sedna and family were captured in a close encounter with a solar sibling". *Monthly Notices of the Royal Astronomical Society* 453: 3158–3163. https://doi.org/10.1093/mnras/stv1803 [^elliot2005]: Elliot, J. L.; Kern, S. D.; Clancy, K. B.; et al. (2005). "The Deep Ecliptic Survey: A search for Kuiper belt objects and Centaurs. II. Dynamical classification, the Kuiper belt plane, and the core population". *The Astronomical Journal* 129: 1117–1162. https://doi.org/10.1086/427395 [^gladman2008]: Gladman, B.; Marsden, B. G.; Van Laerhoven, C. (2008). "Nomenclature in the outer Solar System". In *The Solar System Beyond Neptune*. University of Arizona Press, pp. 43–57. Bibcode 2008ssbn.book...43G. [^bertoldi2006]: Bertoldi, F.; Altenhoff, W.; Weiss, A.; Menten, K. M.; Thum, C. (2006). "The trans-Neptunian object UB313 is larger than Pluto". *Nature* 439: 563–564. https://doi.org/10.1038/nature04494 [^levison1997]: Levison, H. F.; Duncan, M. J. (1997). "From the Kuiper belt to Jupiter-family comets: The spatial distribution of ecliptic comets". *Icarus* 127: 13–32. https://doi.org/10.1006/icar.1996.5637 [^thommes2002]: Thommes, E. W.; Duncan, M. J.; Levison, H. F. (2002). "The formation of Uranus and Neptune among Jupiter and Saturn". *The Astronomical Journal* 123: 2862–2883. https://doi.org/10.1086/339975 [^hahn2005]: Hahn, J. M.; Malhotra, R. (2005). "Neptune's migration into a stirred-up Kuiper belt: A detailed comparison of simulations to observations". *The Astronomical Journal* 130: 2392–2414. https://doi.org/10.1086/452638 [^hansen2005]: Hansen, K. (7 June 2005). "Orbital shuffle for early solar system". *Geotimes*. http://www.geotimes.org/june05/WebExtra060705.html [^tegler2007]: Tegler, S. C. (2007). "Kuiper belt objects: Physical studies". In McFadden, L.-A.; Weissman, P. R.; Johnson, T. V. (eds.), *Encyclopedia of the Solar System* (2nd ed.). Academic Press, pp. 605–620. ISBN 978-0-12-088589-3. [^jewitt2002]: Jewitt, D. C. (2002). "From Kuiper belt object to cometary nucleus: The missing ultrared matter". *The Astronomical Journal* 123: 1039–1049. https://doi.org/10.1086/338692 ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Scattered_disc) : [Wikitube](https://en.wikitube.io/wiki/Scattered_disc) · pinned revision [1368280891](https://en.wikipedia.org/w/index.php?oldid=1368280891) · 2026-09-18 ## Previous hub tags Hubs: `Life_Physics`. Portals: [[PORTAL_Solar_System]]. --- *Solar System portal child articles, wave 1 · 2026-09-18 · drafted · row SOL-022 · explorer state `?obj=scattered`.*