  For seven decades, the widely held view has been that the formation, the
migration and the decay of short-lived starspots explain the constantly
changing light curves of chromospherically active stars. Our hypothesis is that
these deceptive observed light curves are interference of two real constant
period light curves of long-lived starspots. The slow motion of these
long-lived starspots with respect to each other causes the observed light curve
changes. This hypothesis contradicts the current views of starspots. Therefore,
we subject it to eight reproducible tests. Our new period finding method
detects the two real light curves of FK Com. Our hypothesis is a total success:
all real light curve parameters are directly connected to the long-lived
starspots which are also seen in the Doppler images of FK Com.These parameters
are spatially and temporally correlated just like in the Sun, including weak
solar-like surface differential rotation. As for other chromospherically active
stars, all eight reproducible tests also support our hypothesis. It explains
many spurious phenomena: the rapid light curve changes, the short starspot
life-times, the rapid rotation period changes, the active longitudes, the
starspot migration, the period cycles, the amplitude cycles and the minimum
epoch cycles. It also explains why the light curves and the Doppler images give
contradicting surface differential rotation estimates even for the same
individual star, as well as the abrupt 180 degrees shifts of activity (the
flip-flop events) and the long-term mean light curves. We argue that the
current views of starspots need to be revised.
