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Ogledal sem si zanimiv odlomek BBC-jeve oddaje o delu observatorija McDonald v njegovih laserskih meritvah razdalje do lune, ki so očitno natančne do nekaj centimetrov. Observatorij je meril vsak dan in s tem je bil v približno 40 letih od približno leta 1970 do približno leta 2010 pridobljen načrt orbite Lune okoli Zemlje.
Na koncu izvlečka dr. Peter Shelus pravi, da meritve kažejo, da oblika orbite lune ni povsem takšna, kot jo pričakujejo "Newtonove" teorije, kar sem razlagal tako, da orbita ni keplerijanska, verjetno pa je mislil nekaj drugega. Težko je vedeti, ker odlomek samo odreže sredino stavka, zato ni jasno, kaj je natančno povedal.
Na kakšen način je kroženje lune nepravilno v skladu z merilno serijo MacDonald?
Poleg tega opažam, da se je financiranje observatorija v letu 2009 zmanjšalo, tako da teh meritev ne izvajajo več, ampak dve drugi observatoriji pripravljata nove serije. Ali te druge opazovalnice opravljajo dnevne meritve tako, kot je to opravljal observatorij MacDonald?
Gibanje lune, izmerjeno s podatki Lunarnega laserskega dosega, ni takšno, kot ga je napovedal Newton. Kot pravi znanstvenik, s katerim je bil opravljen razgovor, je bil Newtonov model natančen do natančnosti podatkov, ki so mu bili na voljo, in dovolj dober, da je orla pristal na Luni leta '69. Podatki Lunarnega laserskega dosega pa lahko Luno postavijo na natančnost do 3 cm.
Relativistični učinki povzročajo, da Luna odstopa od orbite, ki jo je predvidevala Newtonova mehanika, za približno 1 m, večinoma zaradi posebnih relativističnih učinkov, kot je Lorentzova kontrakcija. Splošna relativnost predstavlja spremembo 10 cm. To je veliko manj kot motenje zaradi Jupitra (približno 1 km). Vendar splošna relativnost v celoti upošteva gibanje lune do natančnosti poskusa.
Vsi testi so v soglasju z Einsteinovo splošno relativnostjo, ki se uporablja za numerično integracijo efemeridov. Nobene spremembe gravitacijske konstante ni zaznati. Vir
Lunino merjenje na Apache Pmazilo Ozimski vrt Lunar Lrazsežnost aserja Operacija.
Na koncu izvlečka dr. Peter Shelus pravi, da meritve kažejo, da oblika orbite lune ni povsem takšna, kot jo pričakujejo "Newtonove" teorije, kar sem razlagal tako, da orbita ni keplerijanska, verjetno pa je mislil nekaj drugega.
To je slaba predpostavka. Nedvomno je mislil nekaj drugega. Tudi Kepler je vedel, da Lunina orbita okoli Zemlje ni Keplerijanska. Newton je poskušal to nekeplerovsko vedenje razložiti z vznemiritvami Sonca. Uspelo mu je razložiti nekatere ključne lunine anomalije, toda matematika njegovega časa ni bila povsem kos izzivu. Na popolno Newtonovo razlago bi bilo treba počakati nekaj sto let, vrhunec pa je bilo delo Ernesta Williama Browna.
Da bi razvil svojo (klasično) lunino teorijo, je moral Brown upoštevati gravitacijske motnje številnih različnih predmetov: Sonca, Venere, Jupitra (in v manjši meri drugih planetov) in tudi nesferično naravo Zemeljsko in Lunovo gravitacijsko polje. Kljub temu je moral Brown uvesti faktor prefinjenosti, da je upošteval 10-ločno nihanje v kotnem položaju Lune. Izkazalo se je, da je bila potreba po tej lupini prenos kotnega momenta iz Zemljine rotacije v Zemljino orbito. To upočasni hitrost vrtenja Zemlje (zaradi česar je čas, ki temelji na vrtenju Zemlje, manj kot zvezdna ideja) in povzroči, da se Luna umakne od Zemlje. Brown je te koncepte sčasoma dodal svoji lunarni teoriji.
Brownov študent Wallace J. Eckert je pozneje razširil Lunino teorijo. Eckert je bil prva oseba, ki je uporabila digitalne računalnike (v nasprotju s človeškimi računalniki) pri problemu napovedovanja Lunine orbite. Bil je tudi oseba, ki je razvila lunine efemeride, ki jih uporablja program Apollo. Eckertovo delo je bilo še vedno klasično v nasprotju z relativističnim.
Retroreflektorji, ki so jih ZDA in Sovjetska zveza postavile na Luno v šestdesetih in sedemdesetih letih, so končno potrebovali uporabo splošne relativnosti za razlago Lunine orbite. Učinki so zelo subtilni, vendar so tam. Zlasti ti odsevniki služijo kot eden najvišjih natančnih preskusov ključnega pravila splošne relativnosti, načela močne enakovrednosti. Načelo enakovrednosti je v več oblikah:
- Galilejevo (ali Newtonovo) načelo enakovrednosti, ki obravnava enakovrednost vztrajnostne in gravitacijske mase ter s tem univerzalnost prostega pada.
- Načelo šibke enakovrednosti, ki pravi, da je gibanje testnih teles z zanemarljivo lastno gravitacijo neodvisno od njihovih lastnosti (to v bistvu ponovno poudarja Galilejevo načelo enakovrednosti v relativističnem smislu),
- Einsteinovo načelo enakovrednosti, ki pravi, da je stanje mirovanja v homogenem gravitacijskem polju fizično enakovredno stanju enakomernega pospeševanja v prostoru brez gravitacije,
- Načelo močne enakovrednosti, ki pravi, da je fizika v kateri koli točki vesolja in časa lokalno opisana s posebno relativnostjo in nanjo ne vpliva prisotnost gravitacijskega polja.
Glede na dovolj natančne meritve je čudna sestava Lune odlična osnova za preizkušanje obeh oblik načela enakovrednosti. Lunina skrajna stran ima veliko debelejšo skorjo kot njena bližnja stran. To pomeni dva kilometra odmika med Luninim masnim središčem in središčem figure. Debela skorja na skrajni strani (večinoma silicij, kisik in aluminij) odmikanega jedra na bližnji strani (večinoma železo in nikelj) bi subtilno vplivala na Lunino orbito, če ne bi veljala šibka oblika načela enakovrednosti. Dejansko je Lunina orbita, merjena z eksperimenti z luninim laserskim merjenjem, odlična osnova za preizkušanje celo načela močne enakovrednosti.
Upoštevajte, da se Newtonova mehanika ne strinja z vsemi, razen z načelom Galilejeve enakovrednosti. Newtonova mehanika se tudi ne ujema z opazovano orbito Merkurja in v manjši meri z opazovano orbito Lune. Alternative splošni relativnosti, ki jih je mogoče preživeti, se strinjajo s šibko obliko načela enakovrednosti, večina pa se strinja z Einsteinovo obliko načela enakovrednosti. Splošna relativnost je skladna z načelom močne enakovrednosti (kot je zelo majhno število alternativ splošni relativnosti).
Nenjutnovo gibanje lune - astronomija
To je laboratorij, ki se uporablja pri uvodnih tečajih astronomije na univerzi v Washingtonu. Prvotno zasnovo je dr. Bruce Balick, spremembe dr. Woody Sullivan in pozneje dr. Doug Ingram. Prvotno je bil oblikovan po vzoru laboratorija z uporabo programske opreme Voyager za Mac. V tej različici so učenci podatke vzeli sami in jih s programom vodili.
Obstaja dolg odsek, ki uporablja gibanje lune na nebu, da študenta popelje na virtualni ogled sončnega sistema. Dejanski datumi in predmeti na nebu bodo seveda odvisni od časa, zato je treba ta laboratorij posodobiti vsakič, ko ga uporabite!
Uvod
Vsi smo Luno opazovali in uživali v njenih številnih fazah, od polmeseca do polne lune. Vsi vemo, da svetel del Lune osvetljuje Sonce in da so faze, ki jih vidimo, nekako povezane z lokacijami Sonca in Lune glede na Zemljo. Te geometrijske relacije raziskujemo v tej vaji. Zanimivo je, da je anketa diplomantov s Harvarda pokazala, da večina meni, da je temni del Lune posledica delov Lune, ki ležijo v senci Zemlje. Njihovo mnenje je genialno, a mrtvo napačno. Ugotovili bomo, zakaj.
Specifični cilji laboratorija so razumeti, kako nastajajo različne faze Lune in zakaj so faze povezane z razlikami v vzhajajočih in zahajajočih časih Lune in Sonca. Preden začnete laboratorij, preberite in razumejte str. 27–31 v besedilu.
Opažanja
Tu je nekaj osnovnih opazovanj nočnega neba kot izhodišča.
- Faza Lune se v enem mesecu spreminja, od nove, do voščenega polmeseca, do prve četrtine itd., In nazaj v novo.
Naredimo podrobno tabelo opazovanj tako, da bomo v enem mesecu spremljali Luno na nočnem nebu, začenši od 27. marca 1994 ob 18. uri po pacifiškem standardnem času v Seattlu in zajemali podatke v intervalih približno 48 ur. Zabeležili bomo datum, lunino fazo, lunin del, ki je osvetljen, kot med Soncem in Luno in kotno velikost Lune (v centimetrih, kjer je 60 arminut ena stopinja na nebo). Da bi nam prihranili nekaj časa, se tukaj zbirajo podatki, ki bi jih zbrali. Če bi to tabelo opazovanj sestavljali sami, bi tekom meseca opazili, da vas Luna popelje na nekakšen "vodeni ogled" sončnega sistema. Tu je nekaj najpomembnejših točk za ta mesec:
- 30. marec - Lunin vzhod je 22:08, nekaj ur po sončnem zahodu. Jupiter najdemo približno 7 stopinj nad Luno, ki je na jugovzhodu neba. Z dobrim teleskopom, Pluton lahko najdemo približno 18 stopinj levo od Lune na nebu.
Videz vseh teh predmetov blizu Lune ni edino presenečenje v podatkih. Opazite, da se kotna velikost celotne Lune s časom spreminja (ne samo osvetljenega dela. Vse skupaj!). Tu pomislite na možnost korelacije med kotno velikostjo Lune in drugimi stvarmi, kot sta osvetljenost ali kot Luna-Sonce. Opazite, kako se zdi, da se kot luna-sonce z osvetljenim delom Lune dviga in spušča. Pomislite, kaj pomeni kot Luna-Sonce in ali se ta navidezna korelacija ujema s tistim, kar smo uganili prej na našem seznamu osnovnih opazovanj.
Analiza
Tu lahko začnete delati. Na vsa spodnja vprašanja odgovorite na svojem papirju. Uporabite milimetrski papir za vse risbe, ki jih želite narediti, preprosto zato, da boste grafe lažje brali in razumeli.
Splošna ideja je ugotoviti, ali je mogoče opažanja uspešno interpretirati v smislu modela - v tem primeru modela, opisanega v 2. poglavju vašega besedila. Upoštevajte, da ta model napoveduje, katere lunine faze vidi kopenski opazovalec na podlagi nekaterih predpostavk o geometriji Zemlja-Luna-Sonce. Vaša naloga je preveriti, ali je model popolnoma skladen z vašimi opazovanji. Seveda so vse lunine faze opazovane, kot je bilo napovedano (sicer ta model sploh ne bi bil nikoli predlagan !!). Zdaj pa si oglejmo, kaj povzroča lunine faze, »Božji pogled«.
Poglavje 2 in slike 2-15 nam povedo, da kot med dvema črtama, eno od Zemlje do Sonca in drugo od Zemlje do Lune, v celoti določa lunino fazo, ki jo bo opazovalec pričakoval. Ta kot smo že izmerili kot tudi lunino fazo, zato mora biti analiza enostavna.
- (1) (14 točk) Narišite diagram, ki opisuje, kje mislite, da je Luna glede na Sonce v vsaki od njegovih 8 glavnih faz (prosite za pomoč, če niste prepričani, kako to storiti) in izpeljite pričakovano razmerje med Soncem -Lunski kot in opazovana lunina faza (to lahko prikažemo s označevanje diagrama s fazami in približnimi koti Sonce-Zemlja-Luna).
Nekatera vprašanja, ki sledijo, lahko zahtevajo, da se sklicujete na besedilo ali zapise predavanj.
- (3) (14 točk) Nariši graf, ki prikazuje Osvetljeni ulomek proti kotu Luna-Sonce. Pravimo, da obstaja povezava med dvema stvaroma, če se zdi, da se v grafu obnašata enako. Ko najdemo korelacijo, začnemo iskati razlog zanjo (o tem razmislite v okviru razprave o korelaciji, vzročni zvezi in znanstvenih študijah pri Pine branju). Ali tukaj obstaja povezava?
(7) (24 točk) Če pogledamo nazaj na diagram, ki smo ga narisali v problemu (1), se zdi, da je Zemlja vsakič, ko smo v fazi polne lune, nameščena med Soncem in Luno. Toda Lunini mrki (pri katerih Zemljina senca delno ali v celoti zakrije) se zgodijo veliko manj pogosto kot enkrat na mesec (bolj kot enkrat ali dvakrat na leto). Zakaj se torej Luna v polni fazi vedno ne zasenči do neke mere? Odgovor na to vprašanje pojasnjuje tudi, zakaj sončnih mrkov nimamo vsak mesec! Narišite diagram, ki bo razložil vaš odgovor.
Nenjutnovo gibanje lune - astronomija
Gibanje in lunine faze
- Orbita: Luna vrti Zemljo s programirano orbito, s časom (zvezden mesec) 27,3 dni [pokriva 12 & deg / dan, skoraj 1 km / s], nagnjena 5 & deg Ni ravno krog [razdaljo lahko izmerimo znotraj nekaj metrov z radijskimi valovi], zato se razdalja Zemlja-Luna v eni orbiti spreminja za približno 13% [poveča se tudi za približno 4 cm / leto!].
- Vrtenje: Luna nam kaže vedno isto stran, ker na revolucijo opravi natanko eno vrtenje. Videli bomo, da obstaja razlog.
- Lunine faze: Glavne so nove, četrtletna (voskovna, upadajoča), polna Luna Sonce vedno osvetli polovico Lune, zakaj torej vidimo različne faze?
- Povezava s časom dneva: Ker je faza Lune odvisna od njenega položaja vzdolž njene orbite, se časi, v katerih lahko vidimo Luno v vsaki fazi, razlikujejo. Kakšen je odnos?
- Zvezdni in lunin (sinodični) mesec: cikel faz se ponovi vsakih 29,5 dni. Zakaj ne 27,3 dni, koliko je obdobje orbite?
- Kaj so oni? Pojma umbra in penumbra Zemlje na Luni.
- Vrste: Lahko so penumralni, delni ali celotni Kje jih je mogoče videti? Celotnost lahko traja dolgo.
- Videz: Med popolnim Luninim mrkom je Luna rdečkasta in ne popolnoma temna Zakaj?
- Vrste: Delno, skupno in obročasto Zakaj se zgodijo? Zakaj so včasih skupni, včasih pa obročasti?
- Vidnost: Samo z majhnega območja, celota pa je le nekaj minut dolga! Toda potem lahko vidimo značilnosti sončnega ozračja (in Lune).
- Kako pogosto? Ugodne sezone mrkov se pojavijo, ko vozlišča orbite prečkajo ekliptiko, približno dvakrat na leto Natančne datume je zelo težko napovedati [18-letni Sarosov cikel] Kako nam je znanost omogočila natančno napovedovanje?
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| The theory began with the model of the sun's motion familiar from de spera (Fig. 1). The sun moves uniformly in the plane of the ecliptic along the circumference of a circle of which the center is displaced from the center of the world along the apsidal line joining apogee and perigee (the points of slowest and fastest motion, called here the aux in oppositio augis respectively). The two centers of reference give rise to two measures of the sun's motus, or longitude along the ecliptic from the conventional starting point of 0 o Arietis (vernal equinox). The mean motus about the center of the eccentric increases uniformly at a rate fixed by dividing 360 o by the length in days of the solar year. The true motus about the earth differs from the mean by an amount called the "equation of the sun", which varies over the year as a function of the mean motus and which depends as well on the eccentricity (the distance e between the two centers) and on the longitude of the apsidal line. Values for the mean motus and the equation were contained in the astronomical tables, and their sum (or at times difference) gave the true motus. |
| The moon and planets required much more intricate arrangements, fundamental to which was the epicycle (Fig. 2). The body was taken to move on a small circle, the epicycle, the center of which itself moved on a circle, the deferent, around the center of the world. In most cases the deferent was an eccentric circle like that of the sun. In the case of the moon (Fig. 3), the eccentric deferent itself constituted a large epicycle turning on a smaller deferent centered on the earth. From a starting position of conjunction with the sun, the center of the deferent revolved from east to west at about 11 o a day, the center of the epicycle from west to east at about 13 o a day (with respect to the earth), and the moon on the epicycle in the same direction as the deferent at about 24 o a day. (As a result of the first two motions, the mean sun always lay midway between the center of the moon's epicycle and the apogee of its deferent.) |
| Uniform motion on the epicycle (mean argument) was measured from its mean aux, a point determined by a line drawn from a point opposite the deferent's center on its small circle. When added to (or, during half the cycle, subtracted from) the "equation of center"' or difference between mean aux and true aux (determined by a line from the earth through the center of the epicycle), the mean argument was transformed into the true argument. The last then led to an "equation of argument" which, added to the mean motus of the epicycle's center, in turn yielded the true motus of the moon. Again, mean values and equations, which depended on mathematical calculations using the moon's fixed parameters, could be found in the tables. |
| The three "outer" planets (Mars, Jupiter, Saturn) each had a fixed eccentric deferent, but the motion of the epicycle's center from west to east along it was made uniform with respect to the center of another circle, the equant. That center lay on the apsidal line joining the earth and the center of the deferent (Fig. 4).
The line from the equant's center through the epicycle's determined the latter's mean aux, from which the mean argument of the planet was measured, increasing from west to east Otherwise, the parameters of the planet's motion were defined as in the moon's model, except that the equation of argument and the equation of center were always equal. Two additional points did require special identification on the planet's epicycle, to wit, the points on the bottom half between which the planet's speed in moving eastward counteracted the epicycle's westward swing along the deferent, thus making the body as seen from earth stop, move eastward, stop, and then resume its normal westward motion. These points of station bounded the arc of retrograde motion. Following the pattern of the Almagest, then, each model of the theorica planetarum analyzed the "true" appearances from the earth into a composite of mean motions and compensating equations and conversely showed how such parameters translated into actually observable measurements. But while the Almagest also provided the apparatus for calculating those parameters from the observational data combined with the mathematics of the models (and thus, incidentally, for tinkering with the models), the theorica assumed that readers had access to on e of the various tables that by the Middle Ages circulated separately from their prototype in the Almagest and that reflected in the mixed provenance of their data the subsequent touch of Italian and Islamic hands. Belonging to an independent genre, a set of tables (called a zîj in Arabic) had its own accompanying instructions, or canons, and could be used without reference to the models. The first tables to enter Europe stemmed from the ninth-century Arabic astronomer and mathematician al-Khwarazmi rendered into Latin by Adelard of Bath in 1126, they were subsequently adjusted for the Christian Era and for various European meridians. Somewhat later they were joined by another set, the Toledan Tables, generally (but uncertainly) ascribed to the eleventh-century astronomer al-Zarqal (Arzachel), whose translated canons were particularly popular. In the 1260s Alfonso X of Spain ordered the compilation of tables designed to be universal preliminary calculations allowed the user to adjust for meridian and epoch. Extant only in the form given them by Johannes de Lineriis and his student Johannes de Saxonia in Paris in the 1320s, and generally accompanied by the canons of one or the other editor, the Alfonsine Tables remained the standard for European astronomy until the sixteenth century. Using the tables with an understanding of the models behind them was made easier by versions of the theorica planetarum that translated the models directly into calculating instruments. The earliest of these in the west was Campanus of Novara's equatorium(ca. 1260), which gave instructions for assembling sets of graduated disks into physical models of the planets circles. With each disk then set from the tables to the appropriate mean motus, a planet's true place appeared under a string stretched from the center of the instrument, through the point marking the planet on the epicycle disk, and onto the ecliptic scale etched on the rim. Inspired perhaps by Arabic instruments, the equatorium underwent improvement in the fourteenth and fifteenth centuries in particular, Campanus' separate models were brought together into a single mechanism allowing for all possible combinations of circles. The replacement of mathematics by mechanics in medieval Europeans' general understanding and use of Ptolemaic astronomy placed an emphasis on its coherence as a total structure, an emphasis reinforced by knowledge of Ptolemy's own attempt at unification in his Planetary Hypotheses and of similar efforts by Arabic cosmologers such al-Farghani (Alfraganus) al-Bitruji (Alpetragius). Of a piece with such structural concerns, but generally critical of them, were the writings of later European cosmologers who worried about the incompatibility of Ptolemaic astronomy with Aristotelian physics. The title of a popular work of this genre by Henry of Langenstein reveals the source of the concern: De reprobatione ecentricorum et epiciclorum, also referred to in some manuscripts as simply Contra theoricam planetarum. Ptolemaic astronomy in the Middle Ages served practical and pedagogical ends rather than theoretical ones. Writers aimed at designing tables and instruments rather than carrying out systematic observations aimed at articulating and improving the system. For the most part, it was only the astrologer who need astronomy at the time, in order to be free of the vagaries of weather and location in determining the positions of the planets. Not until the later fifteenth century, with the work of Johannes Regiomontanus (in particular his completion of George Peurbach's Epitome Almagesti), did theoretical mathematical astronomy begin to attract scholarly interest for its own sake and bring a return to the Almagest itself. When it did, the Ptolemaic system, pressed perhaps precisely by the mechanical and cosmological concerns noted above, had only a short future. Basics of Celestial Motion Best Viewed in Netscape Navigator or Mozilla Firefox. Do NOT use Internet Explorer!Welcome to the Basics of Celestial Motion . This website is designed to introduce the science-shy , the celestially misinformed and anyone who doesn't know how much they really don't know about the Earth, Sun and Moon, to the facts about "celestial motion" or how these "celestial bodies" move in space relative to each other. Well what s there to know? you might ask. The Earth moves around the Sun in a year, the Moon moves around the Earth in a month, and the Earth spins on its own axis in a day. These are really basic facts that we all know and understand.
But do we really understand celestial motion? Popular Astronomy Misconceptions
If you thought the answers were correct then this site is for you!You are not alone .In a well-known video documentary, entitled "A Private Universe", filmed at a 1989 Harvard University graduation, 21 of 23 students, alumni and faculty gave the answers indicated to the two questions above. The video later shows ninth graders from a local high school, with little science education, giving the same answers. And every one of them -- from distinguished Harvard faculty down to "science-shy" ninth-grader -- was wrong! How to Use this SiteEach of the website sections linked below introduces one popular misconception about celestial motion and then provides, in (hopefully) simple terms, a scientifically accurate explanation. The first two sections, The Earth and the Sun, in The Earth and the Moon discuss, respectively, the two popular misconceptions described above regarding the four seasons in phases of the Moon , while the third section, The Major Planets, discusses a third "convenient misconception" about the relative sizes and distances of the planets from Earth. In each case the phenomenology of celestial motion is described in text and images, and key terms are introduced and historical context is provided when important. The final page of each section summarizes the basics of celestial motion, and provides links to other online astronomy resources to help you broaden your understanding and appreciate your new found understanding! WebsitesLuna - Good details from Nine Planets site Luna - Information and statistics from Russian version of American website Books(Notice: The School for Champions may earn commissions from book purchases) Observing the Moon by Peter T. Wlasuk Springer (2000) $39.95 - Reference book for anyone seriously interested in the Moon and its geology Welcome to the Moon: Twelve Lunar Expeditions for Small Telescopes by Robert Bruce Kelsey Naturegraph Publishers (1997) $11.95 - Well written "how to" for novice astronomers See Jupiter’s Galilean moons in motion from Juno’s cameraJuno’s visible camera had a bird’s-eye view of Jupiter’s four largest moons over the last few weeks, recording the satellites in their orbital ballet around the giant planet as the spacecraft approached from above Jupiter’s north pole. Io, Europa, Ganymede and Callisto — Jupiter’s four Galilean moons listed from the innermost to outermost — were discovered in 1610 through a homemade telescope by Italian astronomer Galileo Galilei. Scientists strung together images captured by the JunoCam instrument over 17 days to make the time-lapse movie released early Tuesday, just after Juno slipped into orbit around Jupiter, becoming the second mission to take up residence there. The volcanic moon Io is the closest of the four large moons to Jupiter, completing a lap around the planet once every 42 hours. Europa is next, harbouring a liquid ocean underneath a frozen outer crust. It circles Jupiter every 85 hours, or three-and-a-half days. The largest moon in the solar system, Ganymede, is the third Galilean moon from Jupiter. The satellite is larger than Mercury, and orbits its host planet in seven days. The heavily-cratered moon Callisto circles Jupiter once every 17 days, the duration of Juno’s approach movie selected to show all of the Galilean moons completing at least one orbit. Juno’s arrival at Jupiter on Monday marked the beginning of a 20-month survey, focusing on the gas giant’s deep interior to search for a hypothesized solid core, study the source of its powerful magnetic field, and measure the dynamics of the atmosphere beneath Jupiter’s famous banded cloud tops. Completing a five-year journey, Juno’s approach over Jupiter’s north pole offered a unique view of the moon system. Previous Jupiter missions orbited or flew by the planet closer to the equator. Follow Stephen Clark on Twitter: @StephenClark1. Poglej si posnetek: 3. Gravitacija po Newtonovo (Januar 2023). |
