Puzzling problem: Karsten Schuhmann (left) and Aldo Antognini of the Paul Scherrer Institute inspect the laser system that was used for the laser spectroscopy measurements on muonic deuterium.

I don't know where he got this idea (surely not from the internet), but Eratosthenes estimated the radius of the Earth by looking at two shadows at two different locations on the Earth. This diagram ...

Big problems sometimes come in small packages. The problem with which physicists must now concern themselves measures a mere 0.0350 millionth of a millionth of a millimetre. This is precisely the ...

Using the first new method in half a century for measuring the size of the proton via electron scattering, scientists have produced a new value for the proton's radius in a new experiment. Using the ...

Nonconformists could take a page from the proton’s playbook: The subatomic particle is once again resisting scientists’ attempts to size it up. Everyone agrees the proton is tiny: Its radius is less ...

DENVER — The size of a proton, long thought to be well-understood, may remain a mystery for a while longer, according to physicists. Speaking today (April 13) at the April meeting of the American ...

In astronomy, the point of no return is known as a black hole - a region in space where the pull of gravity is so strong that nothing - not even light - can escape. Now, an international team, led by ...