  Critical collapse of a massless scalar field in spherical symmetry is
systematically studied. We combine numerical simulations and asymptotic
analysis, and synthesize critical collapse, spacetime singularities, and
complex science. First set of approximate analytic expressions near the center
are obtained. We observe that, near the center, the spacetime is nearly
conformally flat, the dynamics is not described by the Kasner solution, and the
Kreschmann scalar is proportional to r^(-5.30), where r is the areal radius.
These features are significantly different from those in black hole
singularities. It is speculated that the scalar field in critical collapse may
be a special standing wave.
