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學習快評丨qibao666888　　北??(bei)京??(jing)天??(tian)文??(wen)館?(guan)科??(ke)普??(pu)教??(jiao)育??(yu)部??(bu)副??(fu)研??(yan)究??(jiu)館?(guan)員??(yuan)曹??(cao)軍??(jun)表??(biao)示??(shi)??，如??(ru)果??(guo)持??(chi)續(xù)??(xu)觀??(guan)察??(cha)土??(tu)星??(xing)??，會??(hui)發(fā)??(fa)現(xiàn)??(xian)光??(guang)環(huán)??(huan)朝??(chao)向??(xiang)地??(di)球??(qiu)的??(de)角??(jiao)度??(du)是??(shi)在??(zai)不?(bu)斷??(duan)變??(bian)化??(hua)的?(de)??，大??(da)概??(gai)十??(shi)幾??(ji)年??(nian)會??(hui)完??(wan)成??(cheng)一??(yi)個??(ge)輪??(lun)回??(hui)??。??今??(jin)年??(nian)3月??(yue)份??(fen)??，地??(di)球?(qiu)正??(zheng)好?(hao)在??(zai)光??(guang)環(huán)??(huan)的??(de)平??(ping)面?(mian)上??(shang)??，因??(yin)此??(ci)看??(kan)上?(shang)去??(qu)就??(jiu)好?(hao)像??(xiang)光??(guang)環(huán)??(huan)消??(xiao)失??(shi)了??(le)一??(yi)樣??(yang)??。　　土??(tu)星秘(xing)環(huán)??(huan)這??(zhe)個??(ge)“大??(da)圓??(yuan)環(huán)??(huan)”的??(de)直??(zhi)徑?(jing)大?(da)約??(yue)是?(shi)28萬??(wan)公??(gong)里??(li)?，相??(xiang)當??(dang)于??(yu)地??(di)月??(yue)距??(ju)離??(li)的??(de)三??(san)分??(fen)之??(zhi)二??(er)?，但??(dan)是??(shi)土??(tu)星??(xing)環(huán)??(huan)的??(de)平??(ping)均??(jun)垂??(chui)直?(zhi)厚??(hou)度??(du)卻??(que)只??(zhi)有??(you)10米??(mi)左?(zuo)右??(you)??。??所??(suo)以?(yi)說??(shuo)?，土??(tu)星??(xing)的??(de)光??(guang)環(huán)??(huan)“薄??(bo)如?(ru)蟬??(chan)翼??(yi)”?，那??(na)它?(ta)是??(shi)由??(you)什??(shen)么??(me)組??(zu)成??(cheng)的??(de)呢?(ne)？??。