I can't imagine a more moving tribute to the final flight of the space shuttle Discovery. This shooting star photographed on March 8 is almost certainly the waste water from Discovery...in other words, a whole lot of astronaut urine.
Jens Hackmann of Weikersheim, Germany took this photo, along with a video that shows Discovery moving across the sky, merrily venting its excess water. The bright spot at the front of the tail is Discovery itself, while everything behind it is the frozen, crystalline water.
These images were captured the day before Discovery landed, and it had plenty of water to pump into space before it could return to Earth. That includes astronaut urine and other waste water, although some of the liquid here seen might be excess fluids from Discovery's fuel cells.
Although it might look like it, Discovery isn't just dumping its astronaut pee on Earth. The water is frozen when its first ejected into space, but contact with the sun's rays makes the ice instantly sublimate straight into water vapor, dispersing the stuff into space. That leaves images like these to be safely enjoyed as a beautiful, disgusting remembrance of our space shuttle program.