Ernest William Brown

**Ernest William Brown** FRS (29 Nuwamba 1866 - 22 Yuli 1938) masanin lissafi ne kuma masanin taurari na Ingila, wanda ya shafe mafi yawan aikinsa yana aiki a Amurka kuma ya zama ɗan ƙasar Amurka a 1923.

Ayyukan rayuwarsa shine nazarin motsi na Wata (Ka'idar wata) da kuma tattara takardun wata masu kyau. Ya kuma yi nazarin motsi na taurari kuma ya lissafa hanyoyin Trojan asteroids.

## Rayuwa da aiki
An haifi Brown a Hull, Ingila, ta biyu cikin 'ya'ya hudu na William da Emma Brown (née Martin). Mahaifinsa da farko manomi ne kuma daga baya ya zama mai sayar da katako. Mahaifiyarsa da ƙaramin ɗan'uwansa sun mutu daga zazzabin cizon sauro a 1870, lokacin da Brown bai kai shekara 4 ba. Shi da 'yan uwansa mata biyu an kula da su ta hanyar mahaifiyar budurwa, har sai mahaifinsa ya sake yin aure bayan shekaru biyar.

### Ilimi da farkon aiki
Brown ta yi karatu a Makarantar Totteridge Park, Hertfordshire (yanzu wani ɓangare na Makarantar Dorset House) da Hull da East Riding College . Bayan ya bar makaranta, ya shiga Cambridge" id="mwMw" rel="mw:WikiLink" title="Christ's College, Cambridge">Kwalejin Kristi, Cambridge, inda ya kammala karatu tare da girmamawa na farko a matsayin Wrangler na shida a lissafi a 1887.  Ya ci gaba da karatun digiri a Cambridge kuma ya yi aiki a karkashin jagorancin George Howard Darwin . A lokacin rani na shekara ta 1888, Darwin ya ba da shawarar cewa ya yi nazarin takardun George William Hill akan Ka'idar wata. Kamar yadda ya fito, wannan ra'ayin don layin bincike shine ya sami babban tasiri a kan sauran rayuwar Brown.

An sanya Brown a matsayin ɗan Kwalejin Kristi a 1889 kuma an zabe shi a matsayin Fellow na Royal Astronomical Society a wannan shekarar. Ya sami digiri na biyu a shekara ta 1891 sannan ya bar Cambridge don ya zama malamin lissafi a Kwalejin Haverford, Pennsylvania. A can, ya tashi da sauri zuwa matsayin Farfesa na Lissafi a 1893. Koyaya, ya ci gaba da yawancin shekaru don komawa Cambridge a lokacin rani, sau da yawa yana zaune tare da tsohon malaminsa, Darwin.

### Aiki a kan motsi na wata
A Haverford, Brown ya ci gaba da karatunsa game da ka'idar wata, kuma ya yi cikakken bita game da aikin masu bincike na baya, kamar Hill, de Pontécoulant, Delaunay da Hansen. An nuna kwarewarsa a fagen ta hanyar buga babban aikinsa na farko, An Introductory Treatise on the Lunar Theory,  a cikin 1896, lokacin da Brown har yanzu bai kai shekaru 30 ba. A shekara mai zuwa, an zabe shi a matsayin Fellow na Royal Society . 

Yayin da aikin Brown ya ci gaba, a hankali ya samo asali da wani shiri na ƙirƙirar sabon ka'idar wata gaba ɗaya. An buga wannan a matsayin jerin takardu a cikin Memoirs of the Royal Astronomical Society tsakanin 1897 da 1908. A shekara ta 1907, an nada shi Farfesa na Lissafi a Jami'ar Yale, tare da shi ya sami yarjejeniya don tallafawa babban aikin lissafin cikakken teburin motsi na wata, bisa ga ka'idar watarsa. Bayan tsawon shekaru 12 da tsada sama da $ 34,000, an buga littafin Brown, Tables of the Motion of the Moon, a 1919.

### Bambance-bambance tsakanin ka'idar da lura
Manufar Brown ita ce samar da daidaitattun abubuwan da suka faru na wata, wanda ya dogara ne kawai da ka'idar jan hankali. Ga 'babban matsala' na tsarin Duniya-Luna-Rana, ya lissafa kalmomi a cikin longitude da latitude har zuwa rashin tabbas na 0.001 arcseconds. Ya kuma haɗa da rikice-rikice saboda sauran taurari (musamman Jupiter da Venus) kuma ya ba da labarin matsalar da ta fi wuya game da yanayin duniya da wata.

Bincike ya nuna cewa teburin Brown sun fi na Hansen, wanda aka yi amfani da shi tun 1857, amma har yanzu akwai babban canji da ba a bayyana ba a cikin ma'aunin tsawon wata na tsari na 10 arcseconds. An gabatar da 'babban lokaci', na girman 10.71 arcseconds da tsawon shekaru 257, don kawar da wannan yadda ya yiwu. Idan aka ba da daidaito na lissafin Brown, dole ne ya zo a matsayin babban takaici don gabatar da wannan gyare-gyare na son rai.

## Manazarta