You have finally hit rock bottom: a span called the Planck length, the shortest anything can get.

The Planck length is simply a unit (like a meter or a mile).

However, this approach fails at short distances of the order of the Planck length.

It is the time required for light to travel, in a vacuum, a distance of 1 Planck length.

As you approach the Planck length, the positions of particles start to become extremely uncertain.

Instead, they are expected to give rise to space and time at distances which are large compared to the Planck length.

The physical significance of the Planck length is a topic of research.

Research on the Planck length is therefore mostly theoretical.

The Planck length - actually a limit on distance itself.

Many studies of nature deal with questions that occur at the Planck length, in which ordinary reality doesn't seem to exist.