Laser beams in a physics laboratory
Callum Fraser / Alamy Stock Photo
A new way of measuring distance using lasers can measure lengths of more than 100 kilometers within a thousandth of the width of a human hair, and could be used to make better telescopes in space.
In laboratory settings, scientists can use lasers to measure distances with extreme precision, down to a few nanometers. But for longer distances of a kilometer or more, the accuracy of these techniques tends to be much lower, within a millimeter.
