ancestor: A predecessor. It could be a family forebear, such as a parent, grandparent or great-great-great grandparent. Or it could be a species, genus, family or other order of organisms from which some later one evolved. For instance, ancient dinosaurs are the ancestors of today’s birds. (antonym: descendant) birds: Warm-blooded dinosaurs with wings that first showed up at least 150 million years ago. Birds are jacketed in feathers and produce young from the eggs they deposit in some sort of nest. Most birds fly, but throughout history there have been the occasional species that don’t. dinosaur: A term that means terrible lizard. These reptiles emerged around 243 million years ago. All descended from egg-laying reptiles known as archosaurs. Their descendants eventually split into two lines. For many decades, they have been distinguished by their hips. The lizard-hipped line are believed to have led to the saurischians, such as two-footed theropods like T. rex and the lumbering four-footed Apatosaurus. A second line of so-called bird-hipped, or ornithischian dinosaurs, appears to have led to a widely differing group of animals that included the stegosaurs …

Pyrolysis (noun, “Py-RAW-leh-sis”) Pyrolysis is a process though which heat breaks down large molecules into smaller ones. It is just one of the chemical reactions that occurs when something is burning. Picture a campfire. The flame may look like a single chemical reaction. But in reality, it comes from multiple reactions that occur step by step. The first step is pyrolysis. In this step, heat breaks open the fuel’s chemical bonds. In the case of a campfire, that fuel is wood. But pyrolysis doesn’t create the campfire’s flame. The next step — combustion — does that. Combustion occurs when the broken-open fuel molecules react with oxygen in the air. Pyrolysis can occur without combustion. For example, if you seal wood in an oxygen-free container and heat it, the wood won’t ignite. Instead, pyrolysis will slowly transform it into charcoal. Pyrolysis typically does not break down fuel as completely as combustion does. That’s why charcoal can still burn to heat up a grill. In contrast, soot collected from a cold campfire typically cannot be burned. Pyrolysis …

ancestor: A predecessor. It could be a family forebear, such as a parent, grandparent or great-great-great grandparent. Or it could be a species, genus, family or other order of organisms from which some later one evolved. For instance, ancient dinosaurs are the ancestors of today’s birds. (antonym: descendant) 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. cell: (in biology) The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells. Most organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell. data: Facts and/or statistics collected together for analysis but not necessarily organized in a way that gives them meaning. For digital information (the type stored by computers), those data typically …

antimatter: Molecules formed by atoms consisting of antiprotons, antineutrons, and positrons. atmosphere: The envelope of gases surrounding Earth, another planet or a moon. atom: The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons. Big Bang: The rapid expansion of dense matter and space-time that, according to current theory, marked the origin of the universe. It is supported by astronomers’ current understanding of the composition and structure of the universe. cosmic: An adjective that refers to the cosmos — the universe and everything within it. cosmic rays: Very high-energy particles, mostly protons, that bombard Earth from all directions. These particles originate outside our solar system. They are equivalent to the nucleus of an atom. They travel through space at high rates of speed (often close to the speed of light). decay: (for radioactive materials) The process whereby a radioactive isotope — which means a physically unstable form of some element — …