Comment on: Comment on "Mysterious abrupt carbon-14 increase in coral   contributed by a comet" Yi Liu et al
  Unfortunately, Liu et al. contains a number of errors and omissions which compromise its conclusions. These have to do with the amount of 14C which is necessary to deposit in the atmosphere in order to see a perturbation like that in 774 AD, and the ability of a comet to do so. 
Adrian L. Melott (University of Kansas)
astro-ph.EP astro-ph.HE astro-ph.SR physics.ao-ph physics.geo-ph