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.
Atom (Krauss book) Atom (Krauss book) Atom: An Odyssey from the Big Bang to Life on Earth...and Beyond is the sixth non-fiction book by the American theoretical physicist Lawrence M. Krauss. The text was published on April 1, 2001 by Little, Brown. Krauss won the Science Writing Award (2002) for this book. In this book Krauss discusses creating parts of an oxygen atom, the primary atoms of the Big Bang. Then he follows it through the remaining history of the Universe. As time has been passing by, the atom was a part of a supernova and star dust, star and planet systems, and,