The Planetary Society Blog
By Emily Lakdawalla http://www.planetary.org/blog/article/00002794/ Door 1 in the Planetary Society Blog 2010 advent calendar Dec. 1, 2010 | 10:05 PST | 18:05 UTC
December really has arrived, and that means that the year is racing to a close. Last year, I counted the days to the New Year with an advent calendar, where each "door" opened onto a global image of a different world in the solar system, all processed by amateurs. As I explained last year, I do realize that the "advent" part of this calendar refers to Christmas, but I'm doing this my own non-denominational way by counting to the New Year instead, which has the added benefit of permitting me to include more places in the solar system. Also, I'll be the last one standing after the Boston Globe Big Picture Hubble and Zooniverse advent calendars run out!
It's not a river, of course. It's one of Venus' enigmatic canali. Venus' canali (singular: canale) look much more like Earth's river valleys than the Moon's sinuous rilles do. This one is about 2 kilometers wide and the part of it in this image is nearly 200 kilometers long.