In 1803, John Dalton proposed a theory of matter in which the smallest particle was an atom. Dalton viewed the atom as solid and indivisible. For nearly a century, that model of the atom proved to be satisfactory for scientific work. Then, in 1897,...

The atomic nucleus is consists of a combination of protons, which have a positive electrical charge, and neutrons, which are electrically neutral. Protons and neutrons are both called nucleons. Every atomic nucleus contains at least one proton, meaning...

The nucleus of an atom is the very small dense region of an atom, in its center consisting of nucleons (protons and neutrons). The size (diameter) of the nucleus is in the range of 1.6 fm (10-15 m) (for a proton in light hydrogen) to about 15 fm (for...

Researchers have discovered that heating an atomic nucleus to 20 billion kelvins causes it to expand by 50% before it fragments. The finding may lead to advances in the understanidng of astrophysical processes, such as the creation of neutron stars. In its normal...

As a by-product of a painstaking search for an extremely rare type of radioactivity, researchers have detected the step-by-step tranformation of a single atomic nucleus through four stages. Starting as a radioactive isotape of radon, this particular nucleus eventually ended up as isotape...

In deep underground laboratories around the globe, a high-tech race is on to spot dark matter, the invisible cosmic glue that's believed to keep galaxies from spinning apart.Whoever discovers the nature of dark matter would solve one of modern science's greatest mysteries and be a...

In deep underground laboratories around the globe, a high-tech race is on to spot dark matter, the invisible cosmic glue that's believed to keep galaxies from spinning apart. Whoever discovers the nature of dark matter would solve one of modern science's greatest mysteries and be...