ʻO ka pilikia o ke kinona o ka Honua ua hopohopo ka poʻe no nā makahiki he nui. ʻO kēia kekahi o nā nīnau nui ʻaʻole wale no ka palapala honua a me ke kaiaola, akā no ka astronomia, akeakamai, physics, mōʻaukala a me nā puke. Nui nā hana a ka ʻepekema o nā au a pau, ʻo ka Antiquity a me ka Enlightenment i hoʻolaʻa ʻia i kēia pilikia.
Nā kuhiakau o nā ʻepekema e pili ana i ke ʻano o ka Honua
No laila, ua manaʻoʻiʻo ʻo Pythagoras i ke kenekulia VI he ʻano pōpō ko kā mākou honua. Ua haʻi ʻia kāna ʻōlelo e Parmenides, Anaximander o Miletus, Eratosthenes a me nā mea ʻē aʻe. Ua alakaʻi ʻo Aristotle i nā hoʻokolohua like ʻole a ua hiki iā ia ke hōʻoia he ʻano poepoe ko ka Honua, ʻoiai i ka wā o nā eclipses o ka Moon, mau ke aka i ke ʻano o ka pōʻai. Ke noʻonoʻo nei i kēlā manawa he mau kūkākūkā ma waena o nā mea kākoʻo o ʻelua mau manaʻo ʻē aʻe, i ʻōlelo kekahi o lākou he pālahalaha ka honua, ʻo kekahi he pōʻai ia, ʻo ke kumumanaʻo o ka sphericity, ʻoiai ua ʻae ʻia e nā manaʻo he nui, pono ka loiloi nui
ʻO ka mea ʻokoʻa ke ʻano o ko mākou honua i ka kinipōpō, wahi a Newton. Ua manaʻo ʻo ia he ellipsoid ia, a e hōʻoia i kēia, ua alakaʻi ʻo ia i nā hoʻokolohua like ʻole. Eia kekahi, ua hoʻolaʻa ʻia nā hana a Poincaré a me Clairaud, Huygens a me dʻAlembert i ke ʻano o ka honua.
Manaʻo o kēia manawa o ka hoʻokalakupua
Ua hana nā hanauna ʻepekema he nui i ka noiʻi kumu e hoʻokumu i ke ʻano o ka honua. Ma hope wale nō o ka lele mua i ka lewa hiki ke hoʻopau i nā kaʻao. ʻĀnō ua ʻae ʻia ke kiko o ka ʻike e loaʻa ana i ko mākou Honua ka kinona o kahi ellipsoid, a he mamao loa ia mai ke kiʻi kūpono, i pālahalaha ʻia mai nā pou.
No nā papahana noiʻi a me ka hoʻonaʻauao ʻokoʻa, ua hana ʻia kahi hiʻohiʻona o ka honua - kahi poepoe, nona ke ʻano o kahi kinipōpō, akā ʻo kēia mau mea āpau loa. Ma kona ʻili, paʻakikī e hōʻike i ka pālākiō a me ke kaulike o nā mea āpau āpau o kā mākou honua. No ka radius, hoʻohana ʻia kahi waiwai o 6371.3 kilomika no nā hana like ʻole.
No nā hana o ka astronautics a me ka geodesy, i mea e wehewehe ai i ke kinona o ka Honua, hoʻohana ʻia ka manaʻo o kahi ellipsoid o ke kipi a geoid paha. Eia nō naʻe, ma nā kikoʻokoʻa ʻokoʻa ka honua mai ka geoid. I mea e hoʻonā ai i nā pilikia like ʻole, hoʻohana ʻia nā hiʻohiʻona ʻokoʻa o ka honua ellipsoids, ma kahi laʻana, kahi ellipsoid kūmole.
No laila, he nīnau paʻakikī ke kinona o ka Honua, ʻoiai no ka ʻepekema o kēia manawa, i hopohopo i ka poʻe mai ka wā kahiko. ʻAe, hiki iā mākou ke lele i ke ākea a ʻike i ke kinona o ka Honua, akā ʻaʻole lawa ka makemakika a me nā helu ʻē aʻe e hōʻike pono ai i ke kiʻi, ʻoiai kū hoʻokahi ka honua, a ʻaʻohe ona ʻano maʻalahi e like me nā kino geometric.
