Image:This illustration of the nuclear landscape shows atomic
isotopes arranged by an increasing number of protons (up) and
neutrons (right). The dark blue blocks represent stable
isotopes, while the lighter blue blocks are unstable isotopes
that have been observed. The gray blocks are possible isotopes
that have not yet been observed. The yellow clouds represent the
drip lines that bound the possible nuclides. A June 2012 study
estimated total of roughly 7,000 nuclides are
possible.Credit:Andy Sproles, Oak Ridge National Laboratory
Scientists have long wondered whether there is a limit to the
number of protons and neutrons that can be clustered together to
form the nucleus of an atom. A new study comes closer than ever
to finding the answer by estimating the total number of nucleus
variations that can exist. The periodic table of elements
includes 118 known species of atoms, and each of these exists
(either naturally or synthetically) in several versions with
differing numbers of neutrons, giving rise to a t