Atom bombardment ejects what appeared to be hydrogen nuclei. By 1920 he had accepted that the hydrogen nucleus is a distinct particle within the atom and named it proton. Neutrons have no electrical charge and have a free mass of 1,839 times the mass of the electron, or , the heaviest of the three constituent particles, but it can be reduced by the nuclear binding energy. Neutrons and protons (collectively known as nucleons) have comparable dimensions—on the order of —although the 'surface' of these particles is not sharply defined. The neutron was discovered in 1932 by the English physicist James Chadwick.
Captain Atom (Atlas Publications) a visual reference to Captain Atom in the Watchmen comic book. In the origin story of Dr Manhattan (who is based on the Charlton Comics Captain Atom), the character is shown rejecting a helmet which is part of his US Government-supplied costume. The helmet design and the overall costume, although a different colour, somewhat resemble that of the Atlas Comics Captain Atom. The British artist, Dave Gibbons, may have been familiar with the Australian character. Captain Atom (Atlas Publications) Captain Atom was an Australian comic book series created and written by Jack Bellew with illustrations by Arthur Mather. It was