A Planck second is the smallest meaningful unit of time. It is what physicist's use to measure things like the beginning of the big bang and what they use to measure light traveling though a vacuum. It can be defined as
one Planck second is
0.000000000000000000000000000000000000000000054 seconds
and Hummers yoctosecond (septillionth) is ONLY a mere twenty million million million times longer!
Yeah, I was gonna get onto Yoctos, but I thought better of it :-)
Oops, just realised I put the time for a zepto second not a Planck unit, thanks
Cg
Oh no in fact I was talking about Planck length, the figure is in metres :-)
Cg