Anthropocene: Term coined by scientists to describe the age in which humans have been the strongest force of change on the planet. It is generally believed to date from at least the dawn of the Nuclear Age (in the middle 1940s), and possibly even earlier — from the beginning of the Industrial Revolution in the early 1800s.
cancer: Any of more than 100 different diseases, each characterized by the rapid, uncontrolled growth of abnormal cells. The development and growth of cancers, also known as malignancies, can lead to tumors, pain and death.
debris: Scattered fragments, typically of trash or of something that has been destroyed. Space debris, for instance, includes the wreckage of defunct satellites and spacecraft.
decay: (for radioactive materials) The process whereby a radioactive isotope — which means a physically unstable form of some element — sheds energy and subatomic particles. In time, this shedding will transform the unstable element into a slightly different but stable element. For instance, uranium-238 (which is a radioactive, or unstable, isotope) decays to radium-222 (also a radioactive isotope), which decays to radon-222 (also radioactive), which decays to polonium-210 (also radioactive), which decays to lead-206 — which is stable. No further decay occurs. The rates of decay from one isotope to another can range from timeframes of less than a second to billions of years.
downwind: A designation for the location of something that is exactly opposite to where the wind is coming from.
element: A building block of some larger structure. (in chemistry) Each of more than one hundred substances for which the smallest unit of each is a single atom. Examples include hydrogen, oxygen, carbon, lithium and uranium.
geographer: A scientist who studies Earth’s features and how the living and nonliving parts of the planet affect one another.
half-life: The time it takes for half of some quantity of a radioactive isotope to decay (transform) into a new isotope
Pacific: The largest of the world’s five oceans. It separates Asia and Australia to the west from North and South America to the east. The term can also refer to island nations that sit within the Pacific Ocean.
radioactive: An adjective that describes unstable elements, such as certain forms (isotopes) of uranium and plutonium. Such elements are said to be unstable because their nucleus sheds energy that is carried away by photons and/or one or more subatomic particles. This emission of energy is by a process known as radioactive decay.
sea: An ocean (or region that is part of an ocean). Unlike lakes and streams, seawater — or ocean water — is salty.
sediment: Material (such as stones and sand) deposited by water, wind or glaciers.
technology: The application of scientific knowledge for practical purposes, or the devices, processes and systems that result from those efforts.
thyroid: A gland in the neck that releases hormones, which play a pivotal role in directing development and metabolism (the use of food as fuel). The gland is relatively small, with two lobes separated by a bridge-like structure. Some therefore refer to its shape as resembling a butterfly.
toxic: Poisonous or able to harm or kill cells, tissues or whole organisms. The measure of risk posed by such a poison is its toxicity.