On Friday I had a post about the golden record on Voyager spacecrafts, and it generated some questions about its scientific value (see comments here). And the answer to that is, well, the record is more about looking at humans and the Earth as a whole, rather than about achieving some "pure" scientific goals. So on a related note, this week is also the 2oth anniversary of the famous Pale Blue Dot image of Earth (listen to the NPR story here about 6mins long). Again, is there a scientific value to that? Not that much. However, it is so much more than that and we should all be glad that NASA decided to finally snap this image. Also, check out this gallery of Views of Earth from the Middle Ages to the Space Age.
What made this image special? Here is Sagan himself talking about the Pale Blue Dot image: