Helium is the simplest element in the periodic table with more than one particle in its nucleus, yet state of the art theory and experiments on it don't add up.

The helium-3 that PSI physicist and ETH Zurich professor Antognini is using in the current experiment lacks not only a neutron in the nucleus, but also both electrons that orbit this nucleus.

The swelling helium nucleus, researchers say, is a sort of mini-laboratory for testing nuclear theory because it’s like a microscope — it can magnify deficiencies in theoretical calculations.

An atom consists of a heavy center, called the nucleus, made of particles called protons and neutrons. An atom has lighter ...

Two protons and a neutron A discrepancy between two different measurements of the charge radius of the helium-3 nucleus may have been reconciled. (Courtesy: Shutterstock) Independent measurements of ...

Many heavy atoms form from a supernova explosion, the remnants of which are shown in this image. NASA/ESA/Hubble Heritage ...

The nucleus of tritium has one proton and two neutrons. When it is struck by a highspeed proton (a nucleus of ordinary hydrogen), the two combine into helium and yield a great jolt of energy (see ...

The swelling helium nucleus, researchers say, is a sort of mini-laboratory for testing nuclear theory because it’s like a microscope—it can magnify deficiencies in theoretical calculations.