Part 5/9:
The Rise of Superstring Theory
The advent of supersymmetry played a critical role in string theory's evolution. Introducing a symmetry between bosons and fermions made sense of various anomalies within the framework of fundamental forces. The 1980s marked the first "superstring revolution," leading to the emergence of distinct versions of superstring theory, each with their unique characteristics but rooted in vibrating strings existing within ten dimensions.
Unfortunately, these five different superstring approaches—Type I, Type II (A and B), heterotic SO(32), and E8 x E8—initially appeared divergent and contradictory, contrasting sharply with the elegance physicists sought.