Abahanga mu bya siyansi basobanura ko Ukwezi kutagaragara buri gihe biturutse ku kuba Isi ifite ikirere ‘atmosphere’. Isi ibaye itagira ikirere, abayituye bajya babona Ukwezi igihe cyose.

Imiterere y’uko Ukwezi kuzenguruka mu Isanzure nayo igira uruhare mu kuba kutagaragarira abari ku Isi buri gihe, kuko iyo kugeze hagati y’Izuba n’Isi igice cyako kimurika kikaba kiterekeye ku Isi, abayituye ntibabasha kukubona.

Impamvu ishobora gutuma abari ku Isi babona Ukwezi haba ku manywa cyangwa nijoro yo ni imwe. Ni urumuri rw’Izuba ruba rukumuritseho rukagaruka (reflection). Bitewe n’uko kwegereye Isi, bihita byoroha ko kugaragara.

Mu nkuru isobanura inkomoko y’umukororombya, hasobanuwemo ko urumuri rw’Izuba ruza ruri mu mirasire y’amabara atandukanye bitewe n’intera ishobora kugeramo.

Ururi mu mirasire igera kure (longer wavelengths) rugaragara mu ibara ritukura, ururi mu mirasire igera hafi (shorter wavelengths) rukagaragara mu ibara ry’ubururu cyangwa ‘Violet’.

Iyo umwuka wa “Nitrogen” n’uwa “Oxygen” yiganje mu kirere cy’Isi itatanyije, ya mirasire igaragara mu ibarara ry’ubururu n’irya ‘Violet’, bituma abari ku Isi babona ikirere cyayo kigaragara mu ibara ry’ubururu.

Iyo ibyo bihuriranye n’uko igice cy’Ukwezi kimurika cyerekeye ku Isi, umucyo wako uganza ya mirasire yatatanyijwe na “nitrogen” na “oxygen” maze abari ku Isi bakakubona ari ku manywa.

Ibyo bikunze kubaho iyo Ukwezi kwegereye Isi, nibura mu ntera y’Ibilometero 384,400.

Hasobanurwa ko Ukwezi gushobora kuboneka ku manywa ku mpuzandengo (average) y’iminsi 25 mu kwezi k’umwaka. Indi minsi itanu ntikugaragara bitewe n’ibyiciro byako (phases of the moon), birimo ikibanza (new moon) n’igisoza (full moon).

Mu cyiciro kibanza Ukwezi kuba kwegereye Izuba cyane, bivuze ko hagati yako n’Isi haba harimo intera nini ituma kutagaragara, naho mu gisoza kugaragara nijoro gusa.

Uko umunsi usa nabyo bishobora kugira uruhare mu kuba Ukwezi kwagaragara ku manywa, kuko nk’igihe igicu kibuditse cyangwa imvura igwa, ntikwagaragara.

Abashakashatsi basobanura ko kuba abatuye Isi babona Ukwezi ku manywa bituturuka ku kuba kuyegereye