Description: 金星是距離太陽第二近的行星，經常被稱為地球的孿生兄弟。它是一顆岩石質的類地行星，半徑略大於 6000 公里，約為地球半徑的 95%，質量是地球質量的 0.815 倍。金星大氣的密度是地球的 90 倍，它的主要成分是二氧化碳，還有濃厚的硫酸雲層覆蓋整個表面。厚重的大氣層產生了非常強烈的溫室效應，導致金星表面溫度高達 460 攝氏度。

金星與太陽的平均距離為 1.08 億公里，約為 0.72 個天文單位（日地距離）。它繞太陽公轉一週需要224.7天。相較於遙遠的恆星，金星繞著它的軸自轉一週也需要很長時間；一個金星日相當於 243 個地球日。這比金星繞太陽運行一週的時間還要長。金星沒有已知的衛星。

金星以羅馬愛神維納斯命名。由於它離太陽很近，因此在日出前或日落後的夜空中經常可以看到金星。在這種情況下，即使用肉眼觀察，金星也非常明亮，傳統上被稱為晨星或昏星。用雙筒望遠鏡可以看到，金星有與月亮相似的相位變化。

Related Terms:

• 天文單位
• 溫室效應
• 太陽系
• 類地行星

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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