Glossary term: 水星
Description: 水星是距離太陽最近的行星,也是太陽系八大行星中最小的一顆。它是一顆岩石質的類地行星,半徑約為 2500 公里,比月球稍大。它的質量是地球質量的 0.055 倍。由於距離很近,從水星看到的太陽亮度是地球的七倍,水星表面受太陽風的影響很大。水星非常稀薄的外大氣層就來自於這種相互作用產生的物質,再加上因頻繁墜落物體而從表面噴出的物質組成的。稀薄的大氣層無法保持行星的溫度,因此水星表面夜間極冷(零下 180 攝氏度),白天極熱(400 攝氏度),因此非常乾燥。
它與太陽的平均距離約為 5800 萬千米,大概是0.39 個天文單位(日地距離),公轉一週需要 不到88 天。水星沒有已知的繞其運行的衛星。
由於水星繞太陽運行的軌道比地球近,因此它在天空中總是顯得離太陽很近。水星因其在天空中的快速運動而得名,它是羅馬神話中速度極快的信使之神。兩個空間探測器(水手 10 號和 信使號)已經訪問過水星,BepiColombo 任務於 2020 年代中期抵達。
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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher The translation of this term and its definition is still awaiting approval
This is an automated transliteration of the simplified Chinese translation of this term
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水星
Credit: 美國國家航空航天局/約翰霍普金斯大學應用物理實驗室/華盛頓卡內基研究所 credit link
License: PD Public Domain icons
月球-水星-昴星團相合
Credit: Giulio Colombo/ IAU OAE
License: CC-BY-4.0 Creative Commons 姓名標示 4.0 國際 (CC BY 4.0) icons
金星和水星的軌跡
Credit: 瑪塞拉-朱利亞-佩斯 (CC BY 4.0)
License: CC-BY-4.0 Creative Commons 姓名標示 4.0 國際 (CC BY 4.0) icons