Sky & Telescope July 2011 Print Issue
Not long ago, Earth was the only planet known to have active volcanoes. Now we know that Jupiter's moon Io and Saturn's moon Enceladus both have lively volcanic plumes that shoot material into outer space, and there are hints that Venus and Mars may have experienced volcanism in the recent past. Moreover, ancient volcanism clearly shaped the surfaces of all the rocky planets, as well as our own Moon. The cover story of the July issue examines all of these examples in detail, and explains how each sheds light on the others.
Speaking of planets, contributing editor William Sheehan has a fascinating article on one of the strangest phenomena of all: the "spokes" that are sometimes observed in Saturn's B ring. Sheehan covers the history of past observations, explores the science behind them, and explains why this is a particularly good time to attempt to observe these elusive spokes.
Sheehan also collaborates with C. Renée James in a lively retelling of Neptune's discovery in 1846, one of the greatest astronomy stories of all time. This is a particularly appropriate time to remember that event, because Neptune is about to complete one full orbit around the Sun since its discovery.
Find out also how to observe and record fine details within the spiral arms of Messier 51, the famous Whirlpool Galaxy. Read the review of a remarkable new telescope and mount from iOptron, and let Gary Seronik explain how and why to collimate the secondary mirror of a Newtonian. Plus the usual great information about what to observe in the night sky this July.
|
