deep space

Saturn’s Moon Titan is visible through binoculars each evening this week. It's where abundant water exists but only in the form of ice, and where pools of fluid methane add a surrealistic touch.

It's widely misunderstood where in the heavens the sun sits at the time of the solstice. Traditionally it was the zodiacal sign of Cancer, hence "Tropic of Cancer" as the earthly place where you’d see the midday sun standing straight overhead. But despite the lingering name, the solstitial sun drifted out of Cancer and into Gemini two thousand years ago. This week: a special solstice.

Acclaimed journalist David Brown's new book "The Mission" tells how one of America's boldest and potentially most revolutionary space missions came to…