A blob of cold beryllium ions has measured the smallest force yet. The charged atoms registered the minuscule tug of an electric field to be 174 yoctonewtons. That’s about equal to the force of Earth’s gravity on a 70-kilogram human divided by a million, then by a billion, then by a billion again, then by four.
Log in
Subscribers, enter your e-mail address for full access to the Science News archives and digital editions.