Rashin rana

Sunspots ne na wucin gadi spots a kan Sun wanda yake duhu fiye da kewayen yankin. Su yankuna ne na rage yawan zafin jiki wanda ya haifar da maida hankali ga Magnetic flux wanda ke hana convection. Sunspots suna bayyana a cikin yankuna masu aiki, yawanci a nau'i-nau'i na polarity na magnetic. Yawan su ya bambanta bisa ga kimanin shekaru 11 na zagaye na rana.

Kowane sunspots ko rukuni na sunspots na iya kasancewa a ko'ina daga 'yan kwanaki zuwa' yan watanni, amma a ƙarshe ya lalace. Sunspots suna fadadawa da kwangila yayin da suke motsawa a fadin Sun, tare da diamita daga  km (10   zuwa  km (100,000 .  Za'a iya ganin manyan sunspots daga Duniya ba tare da taimakon na'urar daukar hoto ba. Suna iya tafiya a saurin dangi, ko motsi mai kyau, na 'yan daruruwan mita a kowane sakan lokacin da suka fara fitowa.

Nuna aiki mai karfi na magnetic, sunspots suna tare da wasu abubuwan da ke faruwa a yankin kamar su coronal loops, sanannun, da abubuwan da suka faru. Yawancin hasken rana da coronal mass ejections sun samo asali ne a cikin waɗannan yankuna masu aiki da ke kewaye da ƙungiyoyin sunspot. Irin waɗannan abubuwan da aka lura a kai tsaye a kan taurari ban da Rana ana kiransu taurari, kuma an auna haske da duhu.

 Tarihi 
An samo rikodin farko na sunspots a cikin Sinanci I Ching, wanda aka kammala kafin 800 BC. Rubutun ya bayyana cewa an lura da dou da mei a cikin rana, inda kalmomin biyu suna nufin ƙaramin duhu. Rubuce-rubucen farko na lura da hasken rana da gangan ya fito ne daga China, kuma ya kasance zuwa 364 BC, bisa ga maganganun masanin tauraron dan adam Gan De (甘德) a cikin kundin tauraron. A shekara ta 28 KZ, masu binciken sararin samaniya na kasar Sin suna yin rikodin abubuwan da aka gani a cikin bayanan mulkin mallaka.

Magana ta farko da aka ambaci wani wuri a cikin wallafe-wallafen Yammacin Turai shine kusan 300 BC, ta masanin Girka na dā Theophrastus, ɗalibin Plato da Aristotle kuma magajin wannan.

Hotunan farko da aka sani na sunspots an yi su ne ta hanyar ɗan majami'ar Ingila John na Worcester a watan Disamba na shekara ta 1128. 

Sunspots an fara lura da su ne a watan Disamba na shekara ta 1610 ta hanyar masanin tauraron dan adam na Ingila Thomas Harriot .  An rubuta abubuwan da ya lura a cikin litattafansa kuma an bi su a watan Maris na shekara ta 1611 ta hanyar lura da rahotanni daga masana tauraron dan adam na Frisia Johannes da David Fabricius. Bayan rasuwar Johannes Fabricius yana da shekaru 29, rahotonsa sun kasance ba a san su ba kuma abubuwan da Christoph Scheiner da Galileo Galilei suka gano da kuma wallafe-wallafen sun sun rufe su. Wataƙila Galileo ya fara lura da hasken rana a lokaci guda kamar Harriot; duk da haka, bayanan Galileo ba su fara ba sai 1612. A cikin shekarun da suka gabata, masu ilimin taurari da yawa na wannan zamanin sun shiga cikin neman sunspots. Ɗaya daga cikin waɗannan shine sanannen masanin taurari Johannes Hevelius wanda ya rubuta ƙungiyoyi 19 a lokacin farkon Maunder Minimum (1653-1679) a cikin littafin Machina Coelestis . 

A farkon karni na 19, William Herschel na daya daga cikin na farko da ya yi hasashen alaka da wuraren rana tare da yanayin zafi a duniya kuma ya yi imanin cewa wasu siffofi na hasken rana zasu nuna karuwar dumama a duniya.  A lokacin da yake fahimtar halayen hasken rana da kuma tsarin tsarin hasken rana, ba da gangan ya ɗauki raƙuman raƙuman rana ba daga Yuli 1795 zuwa Janairu 1800 kuma watakila shi ne farkon wanda ya fara gina tarihin da ya gabata na abubuwan da aka gani ko ɓacewa. Daga nan ya gano cewa rashin wuraren rana ya zo daidai da tsadar alkama a Ingila. Shugaban kungiyar Royal Society yayi sharhi cewa hauhawar farashin alkama ya samo asali ne sakamakon hauhawar farashin kayayyaki .  Bayan shekaru da yawa masana kimiyya irin su Richard Carrington a 1865 da John Henry Poynting a 1884 sun yi ƙoƙari kuma sun kasa gano alaƙa tsakanin farashin alkama da wuraren rana, kuma bincike na zamani ya gano cewa babu wata ma'amala mai mahimmanci tsakanin farashin alkama da lambobin sunspot. 

 Manazarta