Finding Dark Matter

Japanese researchers don't know what dark matter is, but they have managed to map its distribution throughout the universe.

Scientists can't detect dark matter directly. Instead, they infer its existence by the pull its gravity exerts on normal matter. By carefully studying galaxies, the researchers found dark matter is all over. Indeed, galaxies are not isolated systems-- dark matter extends far beyond the visible galaxy to form a web that links all galaxies together, making the cosmos one unimaginably huge, complex structure.

Now, if we can only figure out exactly what the stuff is.