Thirdly, the rippling pattern can be an artefact of gravitational interaction with some other object: maybe another small galaxy or a body of a dark matter. Simulation to the left shows how this is possible - if a smaller object passes near the disc it can cause such ripples.
A recent research detailed in this paper suggests that our Galaxy (Milky Way), may have more complicated structure that we expected. First of all, instead of having a flat disc, the Milky Way has concentric ripples as shown at the picture below. Ripples can only be observed on our side of the Galaxy, due to the other half being obscured by stars and galactic centre. The scientists however expect this pattern to extend throughout the whole disc.
Secondly, if this is true and we extend this rippling pattern outside the assumed size of our Galaxy, we find that there are some over-densities of stars (Monoceros and Tri-Andromeda Ring) that match the ripples and thus they should be treated as part of the Galaxy itself. This would make the Milky Way around 50% bigger than it is considered to be now.
In quantum mechanics, we can treat light (actually any fundamental particle) as both wave and particle. This concept is called wave-particle duality and though in many experiments we have shown that this is true and light behaves as a particle under certain circumstances (for example double slit experiment) and as a wave under others (photoelectric effect), there was never an experiment showing that it behaves as both at the same time.
A recent study detailed in this paper by EPFL group, made it clear that both natures of light can be observed simultaneously. The idea was to confine light with a specific wavelength in a tube, so that we could see standing waves. At the same time, a stream of electrons would be shot perpendicularly to the tube and we would be able to measure the change in energy after the stream passes the tube.
Below, you can find a nice animation explaining the study, done by scientists from EPFL:
Apparently, nobody before made a computer simulation of how a real, scientifically accurate black hole would look like. But behold, the producers of "Interstellar" teamed up with Kip Thorne to provide realistic and surprisingly beautiful renders of a rotating black hole. It's amazing.
Now, a little bit of science. Two interesting things can be seen in this picture. In the movie, the black hole is a spinning (Kerr) black hole and you can see that just by looking at the image of the central object, the sphere that marks the event horizon of a black hole. To a nearby observer, this sphere seems squashed towards the direction of spin and develops a kink on the equator. Interestingly, no study before investigated how a spinning black hole would look like to a nearby observer and all the calculations were usually made for a distant one.
If you're wondering what program did I use to render all the fractals on this site, then Mandelbulber is what you need. Quite remarkably, it's free to use, and offers a great number of possibilities, like hybriding different fractals, ambient occlusion and depth of field. You can even make videos, just by indicating which views should be included. Awesome piece of 3D software.
If you own a tablet or a smartphone, and you want to make some nice interesting 2D fractals, then I highly recommend Fractal Designer. This program is extremely easy to use: you control how the fractal is rendered by graphically indicating which parts of your fractal are self-similar. One more thing I would expect it to have is to include mirroring your images.
Of course, there are many many other fractal renderers available, but these caught my eye lately.