What does our planet look like from very far away? As Carl Sagan famously stated after seeing the famous image of Earth from Voyager, it appears to be a "Pale Blue Dot" - a reminder of how small and delicate our planet is when compared to the size of our Universe.
The opportunity to take a picture of Earth as that "Pale Blue Dot" is actually rather rare. Despite being far away, deep space probes try not to aim their cameras near the inner solar system for fear of blinding their instruments from the bright Sun. The Voyager probe took one picture shortly before shutting off its camera. Previously, Cassini took another photo in 2006 when the Sun was "eclipsed" by the massive planet and its rings. In fact the picture the probe caught of Earth was a side effect of Cassini positioning itself for a nice clear view of Saturn's rings illuminated from behind. Cassini will get another chance to take a full backlit view of those gorgeous rings again…and with that another chance to take a picture of all us on Earth waving back!
On July 19th at 2:27 pm PST (11:27 am EST) turn to the East and wave. Saturn will be there, albeit not visible in the daytime. If you would like to get the exact position of Saturn, the NASA Cassini team has set up a guide here: http://saturn.jpl.nasa.gov/news/waveatsaturn/viewing/
If you would like to submit a photo of yourself, family, or even friends waving, you can submit your photos to the Wave at Saturn Flickr Pool. You can join their Facebook Event to get more up to date information.
While this is a fun event, there is some serious science to be had in this photo opportunity. The last time Cassini took a similar picture, new rings were discovered around Saturn. What will it find this time?