The International Astronomical Union (IAU) is the formal authority for naming celestial bodies. Newly detected minor planets or asteroids get a provisional designation: For example 1989 SG1 was the 32nd object detected in the second half of September 1989. If the object’s orbit is confirmed it receives a permanent number and the discoverer is invited to suggest a name for it. So 1989 SG1 became 7934 Sinatra named in memory of the American singer. This process can take decades. So if you want to make sure that your own name is on the sky you have to discover a comet. Comet 67P/Churyumov-Gerasimenko that was visited by the European spacecraft Rosetta had been named after the Soviet astronomers Klim Ivanovych Churyumov and Svetlana Ivanovna Gerasimenko who had detected it in September 1969. The object is number 67 on the list of numbered comets with “P” standing for periodic.
Who is Miranda? She is the heroine in Shakespeare’s last play “The Tempest”, but Miranda is also the name of a moon of planet Uranus belonging to a set of exceptions. Whereas all of the planets in our solar system and most of the moons are named after Greek and Roman mythology the satellites of Uranus have names that were used by William Shakespeare or Alexander Pope. Dwarf planets also are named after gods, but the Greek and Romans don’t govern the sky alone any more. Haumea discovered 2003 is the Hawaiian goddess of fertility and Makemake found 2005 is a Polynesian creator god.
At the beginning there is a cloud of dusk and gas, as theory goes. The cloud collapses to form a star in the centre surrounded by a rotating disk. (Think of a spinning clump of dough flattening into the shape of a pizza.) Eventually small bits of the material in the disk begin to stick together somewhat like dust bunnies are formed. If they get larger they attract more material thanks to gravity. Planetesimals are formed that grow into planet embryos by collisions. How the embryos turn into big gas giants like Jupiter or small rocky planets like Earth is still discussed. Since the discovery of the big exoplanets that are very near to their host stars most astronomers think that the planets probably migrate through their planetary system during formation. With computer models they try to simulate the process.
At the moment, only five celestial bodies were defined as dwarf planets by the International Astronomical Union (IAU): Pluto, Makemake, Haumea and Eris in the Kuiper Belt (beyond Neptune) and Ceres, in the asteroids belt between Mars and Jupiter. Candidates are Sedna, Orcus, Quaoar and Varuna, all trans-Neptunian objects.
Pluto has long been considered the 9th planet and the farthest away from the sun. But since the discovery of another body with a comparable size to Pluto beyond the orbit of Neptune, the classification of Pluto was reconsidered by the International Astronomical Union (IAU). Pluto is spherical and revolving around the sun, however it is not alone in the area and forms part of the Kuiper Belt where other dwarf planets like Haumea and Makemake have been discovered recently.
The word “planet” originally discribed “wanderers” that moved over the sky in contrast to the “fixed stars”. Only since 2006 there has been an official scientific definition. According to the International Astronomical Union (IAU) to be considered a planet, a celestial body must meet three conditions:
- Be spherical (in hydrostaticequilibrium)
- Turn around its star
- Be in a region where it is alone.
In our solar system there are eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptun.
It is believed that comets and asteroids are the relics of the material that formed the solar system. They would not have evolved and could inform us about the chemical composition, the size, and the formation process of the protosolar nebula. It was long thought that the water found on Earth came from comets, but according to the latest results from Rosetta (ESA’s probe on the Churyumov-Gerasimenko comet) and Dawn (NASA’s probe on the Vesta and Ceres asteroids), it seems more likely that it comes from asteroids.
Umoja wa Kimataifa wa Astronomia (IAU) ni mamlaka rasmi ya kutaja majina ya vitu vya angani. "Planeti ndogo au asteroidi mpya zilizogunduliwa hupata jina la muda: ""1989 SG1"" ilikuwa kitu cha 32 kilichogunduliwa katika nusu ya pili ya Septemba 1989." Ikiwa mzunguko wa kitu hicho unathibitishwa hupokea nambari ya kudumu na mvumbuzi anaalikwa kupendekeza jina kwa ajili yake. "SG1 1989 ilikuwa jina la ""SINATRA"" kwa ajili ya kumbukumbu ya mwimbaji wa Marekani." Utaratibu huo waweza kuchukua miongo mingi. Kama unataka kujua kama jina lako linaonekana angani, lazima upate kometi. Kometi 67P-Gerasimenko ilitambuliwa na wanastronomia wa Urusi, Klim Ivanovich Churyumov na Svetlana Ivanovna Gerasimenko, mnamo Septemba 1969. "Kama ilivyoelezwa hapo juu, ""P"" ni namba 67 katika orodha ya kometi zilizo na nambari, na ""P"" inasimama kwa mara kwa mara." Miranda ni nani? Yeye ni shujaa katika mchezo wa mwisho wa Shakespeare "The Tempest", lakini Miranda pia ni jina la mwezi wa sayari Uranus inayohusiana na seti ya ubaguzi. Mwezi wa Uranus una majina ya hadithi za Kigiriki na Kirumi, lakini pia kuna majina ya William Shakespeare na Alexander Pope. Sayari ndogo-ndogo pia huitwa kwa majina ya miungu, lakini Wagiriki na Waroma hawatawala anga peke yao tena. Haumea (kugundua 2003) ni mungu wa uzazi wa Hawaii na Makemake (kugundua 2005) ni mungu wa uumbaji wa Polynesia. Mwanzoni kuna wingu la giza na gesi, kama nadharia inavyoeleza. Wingu hilo huanguka na kufanyiza nyota katikati iliyozungukwa na diski inayozunguka. (Fikiria kipande cha unga kinachozunguka kikifanyizwa kuwa pizza.) Hatimaye vipande vidogo-vidogo vya vitu vilivyo katika diski huanza kushikamana pamoja kama vile vipepeo wa vumbi. Zikiongezeka, huvutia vitu vingi zaidi kwa sababu ya nguvu za uvutano. Planetesimals hufanyizwa ambazo hukua kuwa viini-tete vya sayari kwa mgongano. Jinsi viini-tete vinavyoweza kugeuka kuwa sayari kubwa zenye gesi kama Jupita au sayari ndogo zenye miamba kama Dunia bado zinazungumziwa. Tangu kugunduliwa kwa sayari kubwa za nje ya dunia zilizo karibu sana na nyota zao, wataalamu wengi wa nyota wanafikiri kwamba sayari hizo huenda zilihama kupitia mfumo wao wa sayari wakati wa kuundwa. Kwa kutumia mifano ya kompyuta wao hujaribu kuiga utaratibu huo. Kwa sasa, kuna nyota tano tu ambazo zinajulikana kama sayari ndogo na Umoja wa Kimataifa wa Astronomia (IAU): Pluto, Makemake, Haumea na Eris katika ukanda wa Kuiper (baada ya Neptune) na Ceres, katika ukanda wa asteroids kati ya Mars na Jupiter. Wagombea ni Sedna, Orcus, Quaoar na Varuna, vitu vyote vya nje ya Neptunian. Kwa muda mrefu Pluto imekuwa ikionwa kuwa sayari ya tisa na iliyo mbali zaidi na jua. Tangu kugunduliwa kwa mwili mwingine wenye ukubwa unaolingana na Pluto, uainishaji wa Pluto ulibadilishwa na Umoja wa Kimataifa wa Astronomia. Pluto ni ya mviringo na inazunguka jua, lakini sio peke yake katika eneo hilo na ni sehemu ya ukanda wa Kuiper ambapo sayari nyingine ndogo kama Haumea na Makemake zimegunduliwa hivi karibuni. Neno " sayari " awali lilimaanisha " watembea-tembea " ambao walihamia angani kinyume na " nyota zisizo na mwendo. " Tangu mwaka 2006 tu, kuna ufafanuzi rasmi wa kisayansi. Kulingana na Umoja wa Kimataifa wa Astronomia (IAU), ili mwili wa angani ufikie hali tatu: kuwa na umbo la mviringo (kwa usawa wa hydrostatic), kuzunguka nyota yake, na kuwa katika eneo ambalo ni peke yake. Katika mfumo wetu wa jua kuna sayari nane: Mercury, Venus, Dunia, Mars, Jupiter, Saturn, Uranus na Neptune. Inaaminika kwamba kometi na sayari ndogo-ndogo ni mabaki ya vitu vilivyofanyiza mfumo wa jua. Hawangekuwa wamebadilika na wangeweza kutujulisha juu ya muundo wa kemikali, ukubwa, na mchakato wa kuundwa kwa nebula ya protosolar. Maji ya dunia yanatokana na kometi, lakini kwa mujibu wa matokeo ya hivi karibuni kutoka Rosetta (ESA's probe on the Churyumov-Gerasimenko comet) na Dawn (NASA's probe on the Vesta and Ceres asteroids), ni uwezekano mkubwa zaidi kwamba maji hayo yanatokana na kometi.