As to what the image depicts, it was constructed by sorting roughly 800,000 scientific papers into 776 different scientific paradigms (shown as red and blue circular nodes) based on how often the papers were cited together by authors of other papers. Links (curved lines) were made between the paradigms that shared common members, then treated as rubber bands, holding similar paradigms closer to one another when a physical simulation forced them all apart: thus the layout derives directly from the data. Larger paradigms have more papers. Labels list common words unique to each paradigm.
Each “list of common words unique to each paradigm” forms a streaming ribbon in the image above. What the authors call a paradigm, I would call a field, or topical area (such as seismology, organometallic chemistry, cryptology, virology, and stellar dynamics), clustered within broader areas (such as geophysics, chemistry, computer science, molecular biology, and astrophysics).