planck length

One millionth of a billionth of a billionth of a centimeter is an incredibly small measurement, smaller than the size of a mother's pinky finger.

You can measure something using a tool at http://holometer.fnal.gov/.

The Planck Constant, the Gravitational Constant, and the Speed of Light can be combined in a certain way to create a length that is equal to 4.05095531 x 10^-35 meters. This is not a proven fact, but it is a definition that many scientists, including Planck, believe is true - that all lengths in the universe must be a multiple of this number.

If we make a proton as big as the entire universe, then the Planck length would be as small as a tree.

Anything shorter than this size is impossible to exist. It is the same size as the smallest possible thing that can exist, called a quantum break. String theory, which is a type of science, starts to exist at this size.

The diameter of a proton is so small that it would take one hundred quadrillion (100,000,000,000,000,000,000) of them to equal 10 to the minus 35 meters.

The laws of physics do not work in the smallest parts of the universe. Even though we can measure the physical universe, we cannot measure the smallest parts because there is no space or time there.

Planck time is the shortest amount of time it takes for light to travel the shortest distance possible.