Ua loaʻa i ka Honua, me ka mahina a me ka hale ʻaina o nā hīnaʻi i loko o ka Solar System, ma kahi o 4.000 miliona mau makahiki i hala aku nei, ka hopena o nā meteorites he nui i ka wā o kekahi o nā hanana ʻino loa i ka mōʻaukala hou: ka 'Great Bombardment'. ʻIke ʻia nā 'ʻeha' o kēlā manawa, i hala he mau haneli miliona mau makahiki, ma nā honua me ka lewa ʻole, e like me Mercury a me ka Moon.
I kēlā manawa, mamao loa, ma kahi o 3.500 biliona makahiki i hala aku nei, ua hāʻule kekahi o kēlā mau meteorites i ka mea i kēia manawa ʻo Western Australia a haʻalele i kona mau wāwae i loko o kahi pūʻulu pōhaku i kapa ʻia ʻo Dresser Formation. A i kēia manawa ua loaʻa iā lākou ka mea kālaihonua ʻo Christian Köberl, mai ke Kulanui o Vienna. Ua hoʻolaha ʻia ka ʻike ʻokoʻa e ka mea noiʻi iā ia iho ma Malaki 14 i kāna kamaʻilio ʻana ma ka 54th Texas Lunar and Planetary Science Conference.
He paʻakikī loa ka ʻimi ʻana, a me ka hiki ke loaʻa i kēia mau pōhaku kahiko loa, ʻoiai ke hoʻopau mau nei ka hana honua a me ka biological (ka lepo, nā pele, nā mea lewa, bacteria, a me nā mea ʻē aʻe) e luku mau a hoʻololi i ka ʻōpala o ko kākou honua. No laila, ʻaʻole like me nā honua ʻē aʻe, ua 'holoi' ka ʻāina i nā meheu o kēlā pae o ka hana ʻino loa. "Inā mākou e nānā i hope ma kahi o 3.500 biliona makahiki," wahi a Köberl, "e loaʻa iā mākou kahi hapa liʻiliʻi loa o ka ʻōpala o ia makahiki."
ʻOiai, ua loaʻa ʻo Köberl a me kāna mau hoa hana i nā hōʻike o ka hopena meteorite i hana ʻia ma 3.480 biliona makahiki i hala aku nei, ʻo ia ka hōʻike mua loa o ka hui ʻana me ka Honua i ʻike ʻia i kēia manawa. Ua loaʻa nā hopena mua loa i loko o ʻelua waihona, hoʻokahi ma Australia a hoʻokahi ma ʻApelika Hema, ʻo ia ka 3.470 biliona a me 3.450 biliona makahiki.
pōā pōhaku
Ua loaʻa nā hōʻike hoʻokuʻi ʻana ma ke ʻano o nā pōʻai pōhaku liʻiliʻi, ʻoi aku ka liʻiliʻi o kēlā me kēia mm i ke anawaena, i loaʻa ma nā papa he nui o nā core drill like ʻole i lawe ʻia ma Western Australia. Hiki ke hana ʻia kēia ʻano spherules ma nā ʻano like ʻole, akā ʻo kekahi o lākou (ʻo ka mea hoihoi loa) ʻo ia ka wā e pā ai ka meteorite i ka lepo a paʻi i nā 'kulu' o ka pōhaku i hoʻoheheʻe ʻia a puni. Ke hoʻopaʻa ʻia, hāʻawi kēia mau kulu i ke ʻano o nā pōʻai pōhaku.
No ka ʻike inā ʻo ia ka hihia a ua hele maoli nā spherules mai kahi hopena, ua kālailai nā mea noiʻi iā lākou me nā ʻano hana ʻoki. "ʻO nā ʻāpana extraterrestrial," i ʻōlelo ai ʻo Köberl, "e hoʻomalu i ka haku ʻana o kēia mau papa spherule."
ʻO kēia mau ʻāpana, kakaʻikahi i nā pōhaku terrestrial akā nui i nā meteorites, loaʻa i nā pākēneka kiʻekiʻe o ka iridium, kekahi isotopes o ka osmium a me nā minela i kapa ʻia ʻo nickel-chromium 'spinels'. He ʻano ʻano dumbbell a me ka waimaka kekahi o nā poʻe, me nā ʻōhū i loko, kahi mea maʻamau i nā pōʻai hopena ma muli o ke ʻano o ka paʻa ʻana ma hope o ka hāʻule ʻana o ka meteorite. ʻO ka ʻoiaʻiʻo, ʻaneʻane like nā huaʻai hou i loaʻa i nā mea noiʻi ma Australia a me ʻApelika Hema.
He mea nui ka ʻimi ʻana i nā hopena meteorite kahiko no ka mea kōkua lākou i ke kūkulu hou ʻana i ka mōʻaukala o ko kākou honua. Me ka hele ʻole hou aku, ua hilinaʻi nā kūlana e kū nei ma ka Honua mua, i ka nui o ka nui o nā meteorites i hoʻopaʻa ʻia i ka manawa i hāʻawi ʻia. "Ua loaʻa kekahi o kēia mau papa spherule - ʻo Köberl i hoʻopau ʻia - i loko o kekahi o kēia mau drill cores. I kēia manawa, ke hana nei nā mea noiʻi e hoʻomaopopo maikaʻi i ke ʻano o ka puʻunaue ʻana o kēia mau papa a ʻike i ke ʻano o ka hopena i kahi ʻike hou o ka pōʻino meteorite mau piliona makahiki i hala.
