My current one.
The Milky Way Galaxy, bustling hub of our galaxy that combines a near-infrared view from the Hubble Space Telescope, an infrared view from the Spitzer Space Telescope, and an X-ray view from the Chandra X-ray Observatory into one multiwavelength picture.
I ended up getting the three original components and blended it together (adjusting some color/light etc) so it looks somewhat better than the composite. (which looks kinda faded, and was also too bright as a wallpaper as it kind of outlighted the icons etc.)
This is a image of the universe. (or rather what we can see of it, our part of the galaxy mostly obscures the rest of the universe).
Remember, this isn't an approximation, this IS the universe we see (or can't see) the various components was colored to make the differences obvious, I just tweaked the balance, cropped it a little etc for my desktop use.
The center of our galaxy is somewhere in that bright swirling light on the right of the image, don't let the bright light fool you, inside
Sagittarius A is the supermassive black hole at the center of the Milky Way. The horror, oh the horror.
Original:
http://www.chandra.harvard.edu/photo/2009/galactic/
You can toggle the different images there, download a larger composite or the component images. (if you'd like to composite them yourself like I did)
Mine is cropped to 1920x1080 size.
PS! THis is a artist conception of how that black hole might look:
http://upload.wikimedia.org/wikipedia/c ... asajpl.jpg
See that tiny black dot in the center?
Oh and the whole image is basically the center of that bright lump in my desktop.