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moon's surface, one trick is to look along the terminator line. There, shadows are causing lunar craters and mountains to stand out in stark relief in contrast to the surrounding plains. This is, after all, the line of lunar sunrise, and in some ways it's similar to the long shadows we see on Earth at sunrise or sunset.
• If you were standing at the location of that line on the moon's surface, you'd be standing at the edge of day, or night. A similar line on Earth's surface passes over you each day at sunset and sunrise. But there is one major difference. On the moon, there's no dusk or dawn, because the moon doesn't have any air to disperse sunlight, and to create the twilight that we see on Earth.
• That's at nightfall and evening on this Tuesday night, July 24, 2012: The waxing crescent moon near the star Spica, and the planets Mars and Saturn.