土星（Saturn）的六颗卫星

探索宇宙（universe）！每天都会精选一张关于我们迷人宇宙的不同图像或照片，并附上一段由专业天文学家（astronomer）撰写的简短说明。

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

说明：土星（Saturn）有多少颗卫星（satellite）？虽然总数可能会持续增加，但截至2026年6月，这颗拥有光环的气态巨行星已确认拥有293颗卫星。这无疑超过了太阳系（solar system）中的任何其他行星，包括仅有115颗已确认卫星的统治级气态巨行星岁星（Jupiter）。土星的大多数已知卫星都是小型的、不规则卫星（irregular satellite）。许多卫星的直径仅有几公里甚至不到一公里，且聚集在倾斜的外部轨道上。然而，在这张8月5日拍摄的清晰土星家族望远镜肖像中，可以看到它最大的六颗卫星。土卫六（Titan）直径为5,150公里，比月球（Moon）更大，甚至比带内行星（inner planet）辰星（Mercury）还要稍大一些，位于右下方。你还可以在画面中发现冰冷的几颗主要卫星：土卫一（Mimas）、土卫三（Tethys）、土卫二（Enceladus）、坤神星（Dione）和土卫五（Rhea）。土卫六是土星已知的第一颗天然卫星（natural satellite），由荷兰天文学家Christiaan Huygens于1655年发现。在太空时代（space age）期间，旅行者号（Voyager）和卡西尼号土星探测器（Cassini）的发现进一步壮大了土星卫星的队伍。

Explanation: How many moons does Saturn have? While the total will likely continue to grow, as of June 2026 the ringed gas giant had 293 confirmed moons. That's easily more than any other planet of the Solar System, including ruling gas giant Jupiter with a mere 115 confirmed moons. Most of Saturn's known moons are small, irregular satellites. Many are only few kilometers to a fraction of a kilometer across and grouped in tilted outer orbits. Six of its largest satellites can be seen here, though, in this sharp telescopic Saturnian family portrait taken on August 5. Larger than Earth's Moon and even slightly larger than inner planet Mercury, Titan, with a diameter of 5,150 kilometers, is at lower right. You can also spot icy major moons Mimas, Tethys, Enceladus, Dione, and Rhea in the frame. Saturn's first known natural satellite, Titan was discovered in 1655 by Dutch astronomer Christiaan Huygens. During the space age Voyager and Cassini discoveries have added to the swelling ranks of Saturnian moons.