Astronomy offers a wonderful blend of observing and imagining. We gaze at Saturn’s rings. They’re real, not abstract at all. Later we hear that its moon Titan has methane pools. Few of us have ever seen liquid methane, but supposedly it looks just like water, so we simply visualize a landscape of lakes and ice boulders. Titan is easy to imagine.
Bob Berman’s Strange Universe: Can you imagine?
November 2009: In Galileo's time and in ours, some science concepts are inconceivable.