芒果视频

基本介紹

赤(chi)道脊是(shi)土星(xing)衛(wei)星(xing)上(shang)存在(zai)(zai)(zai)的(de)一種(zhong)地貌特征，至今已在(zai)(zai)(zai)三(san)(san)顆(ke)土星(xing)衛(wei)星(xing)的(de)發現了該地貌——即較大的(de)土衛(wei)八和較小(xiao)的(de)土衛(wei)十五(wu)、土衛(wei)十八。三(san)(san)顆(ke)衛(wei)星(xing)上(shang)的(de)赤(chi)道脊所在(zai)(zai)(zai)位置都接(jie)近于(yu)衛(wei)星(xing)赤(chi)道。這種(zhong)地貌只存在(zai)(zai)(zai)于(yu)土星(xing)衛(wei)星(xing)上(shang)，但還不確(que)定其形成(cheng)是(shi)否(fou)有共(gong)同原因或者只是(shi)一種(zhong)巧合(he)。三(san)(san)顆(ke)衛(wei)星(xing)上(shang)的(de)赤(chi)道脊都是(shi)于(yu)2005年為卡西尼(ni)號所發現。

土(tu)衛(wei)八上的(de)(de)赤(chi)道(dao)脊的(de)(de)寬達20公里，高(gao)達13公里，長度達1300公里。土(tu)衛(wei)十(shi)五(wu)較(jiao)之土(tu)衛(wei)八小得多，但是(shi)按比例來說，其上的(de)(de)赤(chi)道(dao)脊則更為(wei)顯眼，該地(di)形(xing)使得土(tu)衛(wei)十(shi)五(wu)的(de)(de)形(xing)狀十(shi)分怪異，看起來就像不明飛(fei)行(xing)物(wu)。土(tu)衛(wei)十(shi)八的(de)(de)圖像較(jiao)為(wei)模糊(hu)，但是(shi)仍能(neng)分辨出(chu)類似于(yu)土(tu)衛(wei)十(shi)八的(de)(de)結(jie)構。

至(zhi)(zhi)今仍不(bu)清(qing)楚(chu)這些山脊是(shi)如何形(xing)成(cheng)的(de)(de)(de)，以(yi)及(ji)三顆衛(wei)(wei)星(xing)(xing)(xing)(xing)上的(de)(de)(de)類似地(di)形(xing)是(shi)否存在(zai)著某種(zhong)(zhong)聯系(xi)。由(you)于(yu)土(tu)(tu)衛(wei)(wei)十五(wu)和土(tu)(tu)衛(wei)(wei)十八(ba)的(de)(de)(de)軌(gui)道(dao)(dao)位于(yu)土(tu)(tu)星(xing)(xing)(xing)(xing)環之(zhi)內，因此有(you)人認(ren)為(wei)這兩顆衛(wei)(wei)星(xing)(xing)(xing)(xing)吸附了(le)土(tu)(tu)星(xing)(xing)(xing)(xing)環中的(de)(de)(de)物質，從(cong)而(er)(er)在(zai)赤道(dao)(dao)處形(xing)成(cheng)了(le)這種(zhong)(zhong)山脊。但是(shi)這種(zhong)(zhong)理論并不(bu)適用(yong)于(yu)土(tu)(tu)衛(wei)(wei)八(ba)，因為(wei)該衛(wei)(wei)星(xing)(xing)(xing)(xing)的(de)(de)(de)軌(gui)道(dao)(dao)位于(yu)土(tu)(tu)星(xing)(xing)(xing)(xing)環之(zhi)外。曾(ceng)(ceng)有(you)科(ke)學家認(ren)為(wei)土(tu)(tu)衛(wei)(wei)八(ba)曾(ceng)(ceng)經位于(yu)土(tu)(tu)星(xing)(xing)(xing)(xing)環之(zhi)內，從(cong)而(er)(er)形(xing)成(cheng)了(le)該地(di)形(xing)，后來由(you)于(yu)某種(zhong)(zhong)未(wei)(wei)知原因而(er)(er)被(bei)推出(chu)至(zhi)(zhi)現今的(de)(de)(de)位置(zhi)。與之(zhi)對應，還有(you)一種(zhong)(zhong)觀點認(ren)為(wei)土(tu)(tu)衛(wei)(wei)八(ba)的(de)(de)(de)軌(gui)道(dao)(dao)位置(zhi)并未(wei)(wei)發生變(bian)化，而(er)(er)是(shi)土(tu)(tu)星(xing)(xing)(xing)(xing)環由(you)于(yu)土(tu)(tu)星(xing)(xing)(xing)(xing)的(de)(de)(de)重力場而(er)(er)被(bei)拉至(zhi)(zhi)更(geng)近的(de)(de)(de)軌(gui)道(dao)(dao)位置(zhi)。但是(shi)大多數(shu)科(ke)學家都傾(qing)向(xiang)于(yu)以(yi)下觀點：土(tu)(tu)衛(wei)(wei)八(ba)的(de)(de)(de)赤道(dao)(dao)脊是(shi)由(you)某種(zhong)(zhong)內源性構造活動形(xing)成(cheng)的(de)(de)(de)，而(er)(er)與土(tu)(tu)衛(wei)(wei)十五(wu)和土(tu)(tu)衛(wei)(wei)十八(ba)的(de)(de)(de)赤道(dao)(dao)脊的(de)(de)(de)形(xing)成(cheng)過程沒有(you)聯系(xi)。