Convert Attosecond (as) to Day (Sidereal) (d (sidereal)) instantly.
About these units
Attosecond (as)
An attosecond is 10⁻¹⁸ seconds, one quintillionth of a second. This unfathomably short interval is the domain of electron motion, where electrons shift orbitals, respond to electromagnetic stimuli, and perform quantum tunneling. Attosecond pulses—among the shortest ever created—enable direct observation of electron dynamics inside atoms. These technologies contribute to attosecond physics, a rapidly growing discipline that reveals quantum processes hidden from human intuition. At this scale, classical concepts of motion and time begin to lose meaning; quantum uncertainty and wavefunctions dominate. The attosecond is therefore not just a measurement but a gateway to the most fundamental processes in nature.
Day (Sidereal) (d (sidereal))
A sidereal day is the time Earth takes to rotate exactly 360 degrees relative to the distant stars—about 23 hours, 56 minutes, 4 seconds. In contrast, the solar day is slightly longer because Earth advances in its orbit each day and must rotate extra degrees for the Sun to appear in the same position in the sky. Sidereal days are fundamental to astronomy: telescopes use sidereal time to track stars, which appear in the same position in the sky at the same sidereal moment each night. This unit anchors astronomical observation to the cosmos rather than to the Sun.