Convert Shake (shake) to Day (Sidereal) (d (sidereal)) instantly.
About these units
Shake (shake)
A shake is a playful but scientifically important unit equal to 10 nanoseconds. It originated in the Manhattan Project, where physicists needed a convenient term for very short intervals in nuclear chain reactions. A nuclear fission event occurs on the order of a few shakes, making the unit ideal for modeling neutron capture, reaction propagation, and weapon physics. Today, the shake appears in nuclear engineering literature, plasma physics, and astrophysics—any field involving extremely rapid events. Despite its whimsical name, the shake represents a meaningful scientific compromise: short enough for nuclear events, yet still relatable and easy to calculate.
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.