2025年6月28日
Lunar Farside
Image Credit: NASA / GSFC / Arizona State Univ. / Lunar Reconnaissance Orbiter
Explanation: Tidally locked in synchronous rotation, the Moon always presents its familiar nearside to denizens of planet Earth. From lunar orbit, the Moon’s farside can become familiar, though. In fact this sharp picture, a mosaic from the Lunar Reconnaissance Orbiter’s wide angle camera, is centered on the lunar farside. Part of a global mosaic of over 15,000 images acquired between November 2009 and February 2011, the highest resolution version shows features at a scale of 100 meters per pixel. Surprisingly, the rough and battered surface of the farside looks very different from the nearside covered with smooth dark lunar maria. A likely explanation is that the farside crust is thicker, making it harder for molten material from the interior to flow to the surface and form dark, smooth maria.
Tomorrow’s picture: dark sand
月球的反面
影像提供: NASA / GSFC / Arizona State Univ. / Lunar Reconnaissance Orbiter
说明: 受到潮汐锁定而同步自转的月球，永远以很熟悉的正面朝着地球的住民。不过，如果在绕行月球的轨道上，它的反面也是很熟谙的景观。由月球勘测轨道飞行器的广角相机，所拍摄的影像拼接而成的这幅清晰照片，主题就是月亮的反面。这些影像数据，则是探勘号在2009年11月至2011年2月所拍摄的15,000多幅全月球影像之一部分。上图的最高解析度版本影像，以每像素100公尺的解析度，呈现月球反面的构造。月球的反面破碎且崎岖，外观上与覆盖暗色平滑月海的正面形成了鲜明的对比。造成这种差异的可能原因则是，月球反面的月壳较厚，因此月球内部的熔融物质，难以流出形成平滑的月海。
明日的图片: dark sand
