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基本介紹

赤道脊(ji)是(shi)(shi)(shi)土(tu)星(xing)(xing)衛(wei)(wei)星(xing)(xing)上存在(zai)的一(yi)種(zhong)(zhong)地(di)(di)貌(mao)特征，至今已在(zai)三顆(ke)土(tu)星(xing)(xing)衛(wei)(wei)星(xing)(xing)的發(fa)現了(le)該地(di)(di)貌(mao)——即(ji)較大的土(tu)衛(wei)(wei)八和較小(xiao)的土(tu)衛(wei)(wei)十五(wu)、土(tu)衛(wei)(wei)十八。三顆(ke)衛(wei)(wei)星(xing)(xing)上的赤道脊(ji)所(suo)在(zai)位置都接近于(yu)衛(wei)(wei)星(xing)(xing)赤道。這種(zhong)(zhong)地(di)(di)貌(mao)只存在(zai)于(yu)土(tu)星(xing)(xing)衛(wei)(wei)星(xing)(xing)上，但還(huan)不確定其形(xing)成是(shi)(shi)(shi)否有共同原因或者(zhe)只是(shi)(shi)(shi)一(yi)種(zhong)(zhong)巧合。三顆(ke)衛(wei)(wei)星(xing)(xing)上的赤道脊(ji)都是(shi)(shi)(shi)于(yu)2005年為卡西尼號所(suo)發(fa)現。

土(tu)衛(wei)(wei)八上(shang)的(de)(de)赤道脊的(de)(de)寬(kuan)達(da)(da)20公里(li)，高達(da)(da)13公里(li)，長度達(da)(da)1300公里(li)。土(tu)衛(wei)(wei)十五較之(zhi)土(tu)衛(wei)(wei)八小(xiao)得多(duo)，但是按比例來說，其上(shang)的(de)(de)赤道脊則更為顯眼，該地(di)形(xing)使(shi)得土(tu)衛(wei)(wei)十五的(de)(de)形(xing)狀十分(fen)怪異，看起來就像不明飛行物(wu)。土(tu)衛(wei)(wei)十八的(de)(de)圖像較為模糊(hu)，但是仍(reng)能分(fen)辨出類似(si)于土(tu)衛(wei)(wei)十八的(de)(de)結構(gou)。

至(zhi)(zhi)(zhi)今(jin)仍不清楚這些山脊(ji)是(shi)如何(he)形(xing)成(cheng)的(de)(de)(de)，以及(ji)三顆衛(wei)(wei)星(xing)(xing)(xing)(xing)上的(de)(de)(de)類(lei)似地形(xing)是(shi)否存(cun)在著某(mou)種(zhong)聯系(xi)。由于土(tu)(tu)(tu)衛(wei)(wei)十(shi)五(wu)和土(tu)(tu)(tu)衛(wei)(wei)十(shi)八(ba)的(de)(de)(de)軌道(dao)位(wei)(wei)于土(tu)(tu)(tu)星(xing)(xing)(xing)(xing)環(huan)之內(nei)，因(yin)此有(you)人認(ren)為這兩(liang)顆衛(wei)(wei)星(xing)(xing)(xing)(xing)吸附了(le)(le)土(tu)(tu)(tu)星(xing)(xing)(xing)(xing)環(huan)中的(de)(de)(de)物質，從(cong)而(er)在赤(chi)道(dao)處形(xing)成(cheng)了(le)(le)這種(zhong)山脊(ji)。但是(shi)這種(zhong)理論并不適用于土(tu)(tu)(tu)衛(wei)(wei)八(ba)，因(yin)為該(gai)衛(wei)(wei)星(xing)(xing)(xing)(xing)的(de)(de)(de)軌道(dao)位(wei)(wei)于土(tu)(tu)(tu)星(xing)(xing)(xing)(xing)環(huan)之外(wai)。曾有(you)科學家認(ren)為土(tu)(tu)(tu)衛(wei)(wei)八(ba)曾經位(wei)(wei)于土(tu)(tu)(tu)星(xing)(xing)(xing)(xing)環(huan)之內(nei)，從(cong)而(er)形(xing)成(cheng)了(le)(le)該(gai)地形(xing)，后來由于某(mou)種(zhong)未知原因(yin)而(er)被推出至(zhi)(zhi)(zhi)現(xian)今(jin)的(de)(de)(de)位(wei)(wei)置。與之對(dui)應，還(huan)有(you)一種(zhong)觀點認(ren)為土(tu)(tu)(tu)衛(wei)(wei)八(ba)的(de)(de)(de)軌道(dao)位(wei)(wei)置并未發生變化(hua)，而(er)是(shi)土(tu)(tu)(tu)星(xing)(xing)(xing)(xing)環(huan)由于土(tu)(tu)(tu)星(xing)(xing)(xing)(xing)的(de)(de)(de)重(zhong)力場而(er)被拉至(zhi)(zhi)(zhi)更近的(de)(de)(de)軌道(dao)位(wei)(wei)置。但是(shi)大多數(shu)科學家都傾向于以下(xia)觀點：土(tu)(tu)(tu)衛(wei)(wei)八(ba)的(de)(de)(de)赤(chi)道(dao)脊(ji)是(shi)由某(mou)種(zhong)內(nei)源性構造活動形(xing)成(cheng)的(de)(de)(de)，而(er)與土(tu)(tu)(tu)衛(wei)(wei)十(shi)五(wu)和土(tu)(tu)(tu)衛(wei)(wei)十(shi)八(ba)的(de)(de)(de)赤(chi)道(dao)脊(ji)的(de)(de)(de)形(xing)成(cheng)過程(cheng)沒(mei)有(you)聯系(xi)。