Salt glaciers on Mercury suggest conditions friendly to life — but not life itself — might once have existed on the innermost planet.
With the Perseid shower, a great morning apparition of Mercury, and a chance to see craters scratch out an X on the moon, skywatchers have a busy week ahead!
Bring in winter with a bang with a beautiful, close conjunction and a rare planet-star occultation.
May 9th's transit of Mercury is now history. Countless amateurs — and professionals — watched as the innermost planet had its day in the Sun. It's sometimes the curse of being involved in astronomical outreach that I miss all the action during an important celestial event. For example, I never…