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Umkhangeli zincwadi · Isixhobo 13

Iincopho ze Lagrange: uthelekiso kwisibhakabhaka

Five places around every pair of worlds where a spacecraft can ride along for free, and why the James Webb Space Telescope lives at one of them.

11 min

NASA/JPL/Space Science Institute

Le ncwadi yabhalwa ngu Local Solar System Iqela le-Fundamente lilungu kwaye lingaphuculwa ngumvavanyi oqeqeshiweyo. Ingaba uqeqeshiwe kulo mxholo?

Inqwelomoya engaphandle kwelanga engaphezulu kwilanga kunehlabathi kufuneka ijikeleze ngokucothayo kwaye iphele ngasemva. Kodwa iJames Webb Space Telescope, 1.5 yezigidi zeekhilomitha kude nehlabathi, igcina umgama nathi unyaka wonke. Ihlala kwi Lagrange point, enye yezona ndawo zihlanu apho ukutsala kweziqu ezimbini kunye nokuhamba kweendawo ezijikelezayo kuthelekiswa ngaphandle.

I "esebenzayo enamandla" indawo yomhlaba ye ndoda neplanethi, ibonakala ijikeleza ngeplanethi. Umthamo weplanethi ukhulu kakhulu ngoko ke iziqhoboshi kunye neendawo eziphezulu zenduli zibonakalayo.

Iindawo ezintlanu zokupaka ezikwizulu, kwaye zimbini kuphela ezingenamali.

Bona

Yazise indawo apho ubude buthetha “ukuba ithatha ntoni amandla ukuba ibe apha” kwinto ejikeleza ilanga nehlabathi:

  • Embini ii-wells kwilanga nakwihlabathi.
  • L1 ne L2: iindawo ezimbini ezidlula emlanjeni (izitulo) ngaphaya kwehlabathi, malunga nezigidi ezingama-1.5 zezikhilomitha kude. Ilungelelaniswe, kodwa kuphela: phakamisa inqanawa yenqwelo-moya kwaye ijikeleze. Imisebenzi apho yenza ukulungisa okuncinci kwiiveki ezimbalwa.
  • L3: enye inqanawa ecaleni elunxwemeni lwelanga. Akukho nto isetyenziswayo ihamba apho, kuba ilanga liyivala kuthi.
  • L4 ne L5: iindonga ezimbini ezithambileyo eziphakamileyo 60 amaqondo phambi komhlaba nongaphambili. Ulindele ukuba izinto zijikeleze, kodwa iCoriolis esebenza kujikelezo lijika isikhokelo sibe yi-loop. Zihlala ziqinile, kwaye ubuhle buzigcwalisa: iJupiter’s L4 neL5 zigcina ngaphezulu kwamawaka amabini iTrojan asteroids.

Ubani ohlala khona: I-SOHO ijonge ilanga ukusuka kwiL1 ukusukela ngo-1996; ibona izivunguvungu zelanga phambi kokuba zifike kuthi. IWebb isebenza phantsi kweL2, apho ilanga, umhlaba nenyanga zihlala ngaphaya kwecala elinye, emva kwesikhuseli sayo selanga, zigcina iteleskopu malunga ne-230 °C.

Ukuqonda

Kwisakhelo esijikeleza noMhlaba, into encinci iziva ukutsala kwelanga, ukubamba komhlaba kunye nokujikeleza okujikelezayo ngaphandle. Xa zonke ezintathu zilahlekile, ingahlala ihlala kuloo bhokisi, oko kukuthi, ijikeleze ilanga kwiminyaka emine.

Kwi L1 ne L2 umgama ukusuka kwisiqu esincinane simalunga umda we Hill:

r ≈ a · ∛(m / 3M)

Kwilanga nehlabathi: 149.6 yezigidi zeekilomitha × ∛(3.04 × 10⁻⁶ / 3) ≈ 1.5 yezigidi zeekilomitha. Ukusombulula umlinganiselo ngokuchanekileyo kunika i-1.49 yezigidi zeekhilomitha kwiL1 ne-1.51 yezigidi zeekhilomitha kwiL2.

Umphathi

Kwingxaki yeqela-leentloko ezintathu ezijikelezayo ezimiselweyo, ngemigama kwiyunithi zokwahlula kunye ne μ = m/(M+m), ixabiso elisebenzayo li

Ω(x, y) = −(1−μ)/r₁ − μ/r₂ − ½(x² + y²)

Iincopho ezithe tye zisombulula i∂Ω/∂x = 0 kwi-axis ye-x (i-quintic, esoliweyo ngenani apha); L4 ne-L5 zivelisa amaqela amathathu alinganayo neenxalenye ezimbini. Uvavanyo lokuzinzisa oluthe tye lubonisa ukuba iL1-L3 iyaqhubeka ingazinzi, kwaye iL4/L5 iyazinzi xa i μ < μ_Routh = ½ (1 − √(23/27)) ≈ 0.0385. Iinqanawa zesibhakabhaka kwi L1 ne L2 zibaleka halo okanye Lissajous ijikeleze indawo kunokuba zihlale kuyo.

Zama

I-Hill radius r ≈ a·∛(m/3M) inika umgama omalunga ne L1 ne L2 ukusuka kwisiqu esincinci. Bala le nto kwilanga nomhlaba (a = 149.6 yezigidi zeekilomitha, m/M ≈ 3.04 × 10⁻⁶). Emva koko kwihlabathi nenyanga (a = 384,400 yeekhilomitha, m/M ≈ 0.0123). Yintoni iL2 yehlabathi-inyanga apho NASA's Gateway yacwangciswa khona?

Uvavanyo olukhawulezayo

3 imibuzo ekhawulezayo. Khetha impendulo ukuze ubone ukuba ulungile na.

  1. Iphi kude na kwihlabathi iSun-Earth L2 point, apho iJames Webb Space Telescope isebenza khona?

    1. A 384,000 km
    2. B malunga ne-1.5 yezigidi zeekilomitha
    3. C 36,000 km
    4. D 150 million km
    Bonisa impendulo

    B. malunga ne-1.5 yezigidi zeekilomitha

  2. Yintoni i Lagrange incopho ezinzileyo, ukuze izinto zihlangane khona ngokuqhelekileyo?

    1. A L1 ne L2
    2. B L3 kuphela
    3. C L4 ne L5
    4. D Akukho nanye
    Bonisa impendulo

    C. L4 ne L5 L4 neL5 ziindawo eziphezulu zezinto ezinokubangela ukuba kwenzeke, kodwa iCoriolis effect iguqula ukujikeleza ibe yi-loop ekhawulezayo ngazo, kude kube isiqu esincinci singaphantsi kwe-1/25 yesisindo sesinye esikhulu.

  3. Kutheni iinqanawa zesibhakabhaka kwi L1 ne L2 zifuna ukutsha kwenjini encinci?

    1. A Kuba ezi ntsuku zii-saddles ezingazinziyo: uxinzelelo oluncinci lukhula ngexesha
    2. B Ngokuba uxinzelelo lomoya
    3. C Ukunciphisa iiplanethi
    4. D Ukuhlala kwilanga
    Bonisa impendulo

    A. Kuba ezi ntsuku zii-saddles ezingazinziyo: uxinzelelo oluncinci lukhula ngexesha

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