After Antoine Becquerel's discovery of radioactivity in 1896, there was much speculation as to the nature of the phenomenon. For one thing, it was unclear whether this was an effect produced only by uranium (and, as later discovered by Pierre and Marie...

Radioactivity originates from extraterrestrial sources and terrestrial geologic sources. All elements with more than 83 protons (i.e., an atomic number greater than 83) are radioactive. Some radioactive isotopes also occur in elements with lower atomic...

In 1896, the French physicist Henri Becquerel accidentally found that an ore of uranium, pitchblende, emits an invisible form of radiation, somewhat similar to light. The phenomenon was soon given the name radioactivity and materials like pitchblende...

Radioactivity is defined as the process by which atoms emit particles and high energy rays from their nuclei. Although most elements can be rendered radioactive, the process occurs naturally in only a very few. The modern understanding of radioactivity...

The nucleus of each atom has a specific number of protons and neutrons and is either stable or unstable, depending on the relative number of each. The most stable atoms are those that have an equal number of protons and neutrons. Atoms that are...

Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. This decay, or loss of energy, results in an atom of one type, called the parent nuclide...

The National Nuclear Security Administration proposed a $1.1 million civil penalty against the former manager of a nuclear weapons lab for safety violations that included a researcher spreading radiological contamination to two other states and workers inhaling radioactive substances.The agency announced the notice of violation...

If it weren't for the hot rocks down below Earth's crust, most of North America would be below sea level, report researchers who say the significance of Earth's internal heat has been overlooked.Without it, mile-high Denver would be 727 feet below sea level, the scientists...

If it weren't for the hot rocks down below Earth's crust, most of North America would be below sea level, report researchers who say the significance of Earth's internal heat has been overlooked.Without it, mile-high Denver would be 727 feet below sea level, the scientists...

Two decades after an explosion and fire at the Chernobyl nuclear power plant sent clouds of radioactive particles drifting over the fields near her home, Maria Urupa says the wilderness is encroaching. Packs of wolves have eaten two of her dogs, the 73-year-old says, and...