Unit of distance – interesting facts

August 2, 2010 | In: Science facts

The shortest unit of distance is the “Planck Length,” which is the distance scale at which the known laws of physics break down, and we can no longer describe the structure of space and time. It’s named after Max Planck, the physicist who first proposed that mass and energy come in discrete packets (quanta).

The Planck Length is 0.0000000000000000000000000000000016 centimeters. In other words, one centimeter is about 625 million trillion trillion Planck Lengths!

Physicists suspect that if we could somehow magnify the view of space at the scale of the Planck length, we would see a churning, foaming stew of ever-changing shapes. At this scale, space and time wrap around each other in unimaginable ways.

The longest unit of distance is the “Hubble Length,” which is the radius of the observable universe. That’s about 10-15 billion light years. This unit of length was named after Edwin Hubble, an astronomer who discovered that the universe appears to be expanding.

A light year is the distance light travels in a year, which is about 5,866,000,000,000 miles, or 5.9 trillion miles. The Hubble Length is (minimum) ten billion times that, or 59 sextillion miles! (American definitions for billion, trillion, and sextillion are being used here.)

Cosmologists (scientists who study the history of the universe) suspect that the universe may go on far beyond the edge of what we can see. No one knows just how big it really is.