A single atom can gauge teensy electromagnetic forces

The unit of measure, a zeptonewton, is equal to one billionth of a trillionth of a newton

illustration of a laser hitting a charged atom

FEEBLE FORCE  Scientists detected a tiny force using a charged atom (illustrated as a red sphere), which moved (orange) when pelted with laser light (purple). A lens focused light emitted from the atom into a moving image (black arrow).

V. Blūms et al/Science Advances 2018

Zeptonewton
ZEP-toe-new-ton n.