Tuesday, November 29, 2005
Lessons from Tethys
The massive impact basin Odysseus (280 miles across) is at top. Note a cluster of mountain peaks at the center of it. The crater on the lower rim is Melanthius. The central peak is barely in the light, as you see. Tethys itself is only 665 miles across, almost a third of our moon's diameter.
Aside from posting a pretty picture from Saturn, this shot illustrates how valuable observing our moon is when it's not full. When full, it is easy to be overwhelmed by the beauty and brightness. But astronomers value what shadows tell them. Observing the moon on consecutive nights near the day-night terminator is really fascinating. Even over a few hours, one can see subtle changes as the lunar landscape rotates into or out of the sunlight.
