# He aha ke Ala Waiū ma ka Hōkū
## Hoʻolauna
ʻO ke Ala Waiū, i ʻike ʻia hoʻi ʻo ke Ala Waiū, ʻo ia kekahi o nā triliona o nā galaxies i hoʻopuehu ʻia ma ke ao holoʻokoʻa. ʻO kēia galaxies ka home o kā mākou ʻōnaehana lā, nona ka honua Honua a me nā mea lani like ʻole. He mōʻaukala lōʻihi ko ke Ala Waiū o ka nānā ʻana o ke kanaka a ua hoʻohuli nui i ka hoʻomohala ʻana o ka ʻike hōkū. E nānā hou kēia ʻatikala i nā ʻano like ʻole o ke Ala Waiū, me kona ʻano, ka haku mele ʻana, ka mōʻaukala nānā ʻana, a me nā ʻike hōkū hou e pili ana i kēia galaxies.
## ʻAno o ke Ala Waiū
Ma keʻano laulā, he galaxy ʻōwili ka Milky Way galaxy a he nui nā ʻāpana nui:
### 1. Pā hōkū Galactic
ʻO ka disk galactic ka ʻāpana pālahalaha, ʻano wili kahi e noho ai ka hapa nui o nā hōkū, me ka Lā. He 100.000 a 120.000 mau makahiki māmā ke anawaena o ka disk a he 1.000 mau makahiki māmā ka mānoanoa. Aia ka disk i nā lima wili e wili ana i waho mai ke kikowaena a loaʻa nā hōkū ʻōpio, ke kinoea, a me ka lepo.
### 2. Lima ʻōwili
ʻO nā lima wili kahi hiʻohiʻona hiʻona o nā galaxies wili, me ka Milky Way. Loaʻa i kēia mau lima wili nā hōkū ʻōpiopio ʻālohilohi he nui, nā nebulae, a me nā wahi hoʻokumu hōkū. Loaʻa i ka Milky Way kekahi mau lima wili nui, me ka Perseus Arm, ka Sagittarius Arm, a me ka Scutum-Centaurus Arm.
### 3. Puʻupuʻu
He ʻāpana poepoe a mānoanoa ʻo Bulge o ka ʻāpana waena o ka Milky Way, nona nā hōkū kahiko a me kahi lua ʻeleʻele nui loa i ʻike ʻia ʻo Sagittarius A. Aia ka Bulge ma waenakonu o ka disk galactic a he anawaena ma kahi o 10.000 a 20.000 mau makahiki māmā.
### 4. Aloha
He ʻāpana poepoe ka halo e hoʻopuni ana i kahi galaxy. Aia i loko o kēia halo nā hōkū kahiko, nā hui poepoe, a me nā mea pouli ʻike ʻole ʻia akā he umekaumaha. Hiki i ka halo ke hoʻolōʻihi i kekahi mau haneli tausani mau makahiki māmā mai ke kikowaena galactic.
## Ka Hoʻokumu ʻana o ke Ala Waiū
He galaxy waiwai a paʻakikī hoʻi ʻo Milky Way. Aia i loko o kona ʻano nā mea like ʻole a me nā ʻano, e like me:
### 1. Hōkū
ʻO nā hōkū nā ʻāpana nui o ka Milky Way. Ua manaʻo ʻia aia ma waena o 100 a me 400 biliona mau hōkū ma kēia galaxy. Loaʻa kēia mau hōkū i nā nui like ʻole, nā makahiki, a me nā pae o ka ulu ʻana. He ʻōpiopio a ʻālohilohi kekahi mau hōkū, aʻo kekahi paha he ʻelemakule a pouli.
### 2. Kinoea a me ka Lepo
Ma waho aʻe o nā hōkū, aia pū kekahi i loko o ka Milky Way ka nui o ke kinoea interstellar a me ka lepo. ʻO kēia kinoea, i haku ʻia me ka hydrogen a me ka helium, hana i nā ao nebular kahi e hoʻokumu ʻia ai nā hōkū hou.
### 3. Mea ʻEleʻele
ʻOiai ʻike ʻole ʻia a ʻike ʻole ʻia ka mea pouli ma o ka radiation electromagnetic, he mea nui ia no ke ʻano o ka Milky Way. Hāʻawi ia i ka nuipa hou e kōkua ai i ka hoʻopaʻa ʻana i ka neʻe ʻana o nā hōkū a me ke kinoea i loko o ka galaxy.
### 4. Nā Lua ʻEleʻele Nui Loa
Aia ma waenakonu o ka Milky Way kahi lua ʻeleʻele nui loa i ʻike ʻia ʻo Sagittarius A. He ikaika loa ka umekaumaha o kēia wahi ʻaʻole hiki i ka mālamalama ke pakele. Ua manaʻo ʻia he 4 miliona mau manawa ka nui o kēia lua ʻeleʻele ma mua o ka Lā.
## Moʻolelo o ka Nānā ʻana
Ua hoʻomau ʻia nā nānā ʻana o ka Milky Way no nā kenekulia. ʻO kekahi mau hanana koʻikoʻi i ka noiʻi ʻana o Milky Way:
### Nā Nānā Mua
Ua ʻike mua ʻia ke Ala Waiū e nā lāhui kahiko ma o ka nānā ʻana i nā maka me ka ʻole o nā mea kani. Ua hāʻawi nā Helene, Roma, a me nā poʻe ʻē aʻe i nā inoa a me nā moʻolelo moʻolelo i ka mālamalama palupalu i ʻike ʻia ma ka lewa pō.
### Hoʻokahuli Telescope
ʻO ka hoʻololi ʻana o ke kelepona ʻike maka i ke kenekulia 17 i hiki ai i nā kānaka ʻepekema e like me Galileo Galilei ke nānā aku i ka nui o nā hōkū o ke Ala Waiū. Ua hoʻokumu kēia i ke kahua no ka hoʻomaopopo ʻana he hōʻiliʻili nui o nā hōkū ke Ala Waiū.
### Ka ʻIke ʻana i ke ʻAno o nā Galaxy
I ke kenekulia 20, ua hoʻohana ʻo Edwin Hubble a me nā mea kilo hōkū ʻē aʻe i nā telescope hou e aʻo i ka Milky Way me nā kikoʻī hou aku. Ua hoʻoholo lākou he galaxy ʻōwili ka Milky Way me nā lima ʻālohilohi. Ua alakaʻi kēia noiʻi i ka hoʻomohala ʻana o nā kumumanaʻo e pili ana i nā galaxies a me ke ʻano o ke ao holoʻokoʻa.
## Nā ʻIke Hou Loa
Me ka holomua o ka ʻenehana, ke hoʻomau nei ko mākou ʻike i ka Milky Way i ka hoʻonui ʻia. ʻO kekahi mau mea i ʻike hou ʻia ma ka ʻike hōkū:
### Nānā ʻana i ka Infrared a me ka Radio
Ua hāʻawi mai nā nānā ʻana ma ka infrared a me ka radio spectrum e nā telescopes e like me ka Spitzer Space Telescope a me ALMA (Atacama Large Millimeter/submillimeter Array) i nā ʻike hou i ka hoʻokumu ʻia ʻana o nā hōkū a me nā molekala paʻakikī i loko o ko kākou galaxy.
### Misiona Gaia
Ua hāʻawi ka misionari Gaia a ka European Space Agency (ESA) i ka ʻikepili kikoʻī loa e pili ana i nā kūlana a me nā neʻe ʻana o nā hōkū he 1 biliona ma ka Milky Way. Ke kōkua nei kēia ʻikepili i nā kānaka ʻepekema e kūkulu i kahi palapala ʻāina ʻekolu-dimensional o ko kākou galaxy a hoʻomaopopo maikaʻi i kona dinamika a me ka ulu ʻana.
### Noiʻi Mea ʻEleʻele
ʻO ke aʻo ʻana i nā mea ʻeleʻele kekahi o nā kumuhana hoihoi loa i ka ʻike hōkū ʻo Milky Way. Hoʻohana nā mea kilo hōkū i nā ʻano hana like ʻole e hoʻāʻo ai e ʻike a hoʻomaopopo i nā ʻano o kēia mea ʻike ʻole ʻia. ʻO nā nānā ʻana i ka lensing umekaumaha a me ka hoʻohuli ʻana o nā galaxy kekahi o nā ʻano hana i hoʻohana ʻia e ʻimi i nā mea pohihihi o nā mea ʻeleʻele.
### Ka ʻImi ʻana i ka Lua ʻEleʻele
ʻO ka ʻike ʻia ʻana o kahi lua ʻeleʻele ma ke kikowaena o ka Milky Way e wehe ana i ka puka no ka noiʻi hou aku i ka umekaumaha koʻikoʻi a me ka relativity laulā. I kēia mau lā iho nei, ua hopu ka Event Horizon Telescope (EHT) i ke aka o kahi lua ʻeleʻele ma kekahi galaxy ʻē aʻe, ʻo M87, e hoʻomākaukau ana i ke ala no nā nānā ʻana o Sagittarius A i ka wā e hiki mai ana.
## Hopena
He galaxy paʻakikī loa ʻo Milky Way i waiwai i nā ʻano ʻāpana like ʻole a me nā hanana astronomical. Mai kona mau lima wili mālamalama a hiki i kona lua ʻeleʻele supermassive waena, ke hoʻomau nei ʻo Milky Way i ke kikowaena o ka noiʻi a me nā nānā ʻana e hōʻike ana i nā ʻike hou i ke ao holoʻokoʻa. Me nā holomua ʻenehana a me nā hana hui pū ʻana i loko o ke kaiāulu ʻepekema, e hoʻomau ka ulu ʻana o ko mākou ʻike o kēia galaxy, e hoʻokokoke mai ana iā mākou i kahi ʻike hohonu o ko mākou wahi ma ka cosmos.
ʻO ka mea hope loa, ʻo ke aʻo ʻana i ka Milky Way ʻaʻole wale nō e hāʻawi i nā ʻike ʻepekema
