These may look similar, but are vastly different. On the left we have Galaxy M101, and on the right Typhoon Rammasun. Rammasun was only a thousand kilometers or so across while M101 (aka the Pinwheel Galaxy) spans about 170,000 light-years. These do look amazingly alike tho, each with arms exhibiting the shape of a simple and beautiful mathematical curve known as a logarithmic spiral..
Article Link: http://apod.nasa.gov
