Convert Year (Sidereal) (y (sidereal)) to Femtosecond (fs) instantly.
About these units
Year (Sidereal) (y (sidereal))
A sidereal year is the time it takes Earth to complete one full orbit relative to distant fixed stars, lasting approximately 365.25636 days. This is the "true" orbital period of Earth in space, unaffected by precession-related shifts of the equinoxes. Sidereal years are used in celestial mechanics, spacecraft navigation, and modeling solar system dynamics. The slight difference between the tropical and sidereal year (about 20 minutes) reveals how Earth's wobbling axis alters how we perceive time, creating two distinct astronomical year definitions.
Femtosecond (fs)
A femtosecond equals 10⁻¹⁵ seconds, a staggering scale where fundamental molecular motions occur. Chemical bonds vibrate, break, and rearrange on femtosecond timescales. Ultrafast spectroscopy—pioneered by Ahmed Zewail, who won the Nobel Prize for this work—uses femtosecond laser pulses to "freeze" molecular reactions and observe them in real time. Femtosecond lasers allow extraordinary precision in surgery and microfabrication, producing minimal heat diffusion and ultraclean cuts. At this scale, time ceases to be a continuous blur and becomes granular in terms of molecular motion, giving rise to the field of femtochemistry and revolutionizing our understanding of reaction dynamics.