kilosecond ks minutes, hours, days (1 ks = 16 min 40 s = 1,000 s) 1 ks: record confinement time for antimatter, specifically antihydrogen, in electrically neutral state as of 2011. 1.8 ks: time slot for the typical situation comedy on television with advertisements included
A femtosecond is the SI unit of time equal to 10-15 or 1 ⁄ 1 000 000 000 000 000 of a second; that is, one quadrillionth, or one millionth of one billionth, of a second. For context, a femtosecond is to a second as a second is to about 31.71 million years; a ray of light travels approximately 0.3 μm (micrometers) in 1 femtosecond, a distance comparable to the diameter of a virus.