The Saturn System was a free book from NASA at the completion of the Cassini-Huyghens space expedition. I downloaded it like a shot. I chose to look at it now as I needed to do some research on planetary ring
X is for Exoplanets #AtoZChallenge2018
Exoplanets are planets outside our solar system. I had already prepared an X for this year’s A to Z. Then I watched this month’s Sky At Night programme on the search for life on Mars. That made me realise that