This picture I saw long ago in a schoolbook. It should show the world view in the Middle Ages. In this view there's a point where the earth and the heavens met. The earth is a disc. And behind the firmament is a second sky (Cosmos, Kristallhimmel, Feuerhimmel) with the cosmic machinery. The wheel in a wheel is a symbol for God.
Now to some new things (for me): This is not a woodcut from the Middle Ages. It is a book-illustration of Camille Flammarion's 1888 "L’atmosphère. Météorologie populaire". More information here: http://en.wikipedia.org/wiki/Flammarion_engraving. The artist is unknown.
It is a wood engraving, but I think, its based on a ink drawing.
Earth, a Bitmap Trace. The Gimp was used to scale, reduce colours. This was a challenge to find the right settings to create a smaller file yet be visually pleasing to look at. Enjoy!
Original Public Domain file is at http://upload.wikimedia.org/wikipedia/commons/9/97/The_Earth_seen_from_Apollo_17.jpg
Planet Saturn Bitmap Trace. This was a challenge to get it to a small size. The Gimp was used to clean up, rescale and reduce colour. I Love Inskcape! The original public domain image can be found at http://upload.wikimedia.org/wikipedia/commons/e/e3/Saturn_from_Cassini_Orbiter_%282004-10-06%29.jpg
The Planet Mercury Bitmap Trace. The Gimp was used to scale, reduce colours & to clean up image. Inkscape simplify path was not used. Original Public Domain Image can be found at http://upload.wikimedia.org/wikipedia/commons/3/30/Mercury_in_color_-_Prockter07_centered.jpg
This is clipart converted and broken apart that has been released into the public domain because the document says so, and its from NASA, a USA government agency. The publication is called "The Brain in Space:"
http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/The.Brain.in.Space.html
Planet Uranus Bitmap Trace. The Gimp was used to scale, reduce colours and clean up image. The original public domain image can be found at http://upload.wikimedia.org/wikipedia/commons/3/3d/Uranus2.jpg
Planet Neptune Bitmap Trace. The Gimp was used to scale, reduce colours. Original Public Domain file can be found at http://upload.wikimedia.org/wikipedia/commons/0/06/Neptune.jpg
A Bitmap Trace of a Nasa Public Domain image of Jupiter. Wikipedia en.wikipedia.org/wiki/File:Jupiter_by_Cassini-Huygens.jpg
Used The Gimp to clean up, scale and reduce colours. Used the simplify function in Inkscape to reduce size of svg file.