The fine people over at the International Guild of Knot Tyers Forum talk knots. On Mars.
The Anatomy of Spiral Arms, shows how galaxies naturally evolve to form grand-design two-arm spirals. The Hubble Ultra Deep Field in 3D. [more inside]
On Truth and Reality. Despite several thousand years of failure to correctly understand physical reality (hence the current postmodern view that this is impossible) it is actually very simple to work out how matter exists and moves about in Space. The rules of Science (Occam's Razor / Simplicity) and Metaphysics (Dynamic Unity of Reality) require that reality be described from only one single source existing, as Leibniz wrote: "because of the interconnection of all things with one another." [more inside]
Dr. Jeannine Mosely finishes building a level-3 Menger sponge from business cards. You can also build your own, though Dr. Mosely warns, "[a] level 4 sponge would require almost a million cards and weigh over a ton. I do not believe it could support its own weight — so a level 3 is the biggest sponge we can hope to build." (related)
Grigory Perelman, awarded the Fields Medal for his work on the Poincare Conjecture, talks to the New Yorker.