ScienceAugust 4, 2026
femtosecond
FEM-tuh-sek-und
Definition
A unit of time equal to one quadrillionth of a second, used here to describe the high-speed capability of imaging molecular processes.
Etymology
Derived from the Danish/Norwegian 'femten' (meaning fifteen) combined with 'second,' as a femtosecond is 10 raised to the negative 15th power of a second. It was adopted into the International System of Units (SI) in 1964.
In the news
The article uses the term to highlight the extremely short time scale—a femtosecond—at which researchers can now capture video of molecular orbitals. This scale is vital for observing atomic-level dynamics that occur faster than traditional cameras can record.
Quantum fluid reveals hidden states that can be switched with a magnetic field
Read the full article ↗phys.org