using spectroscopy (or breaking up the radiation we receive from stars using a spectroscope into its constituent wavelengths) astronomers can tell what stars are made of. how cool is that?
a projection of a hypercube (or a cube in four dimensions) into three dimensions
calabi-yau manifold. this is what the tiny invisible dimensions of the universe look like! maybe.
the julia set. a lovely fractal.
i heart carl sagan
platonic solids. in 450 bc you could get killed for flapping your lip about the dodecahedron
a projection of the three dimensional cube into two dimensions