Descriptionary

Formalhaut-B orbiting the star Formalhaut, the first planet outside our solar system captured vis­ibly in a photograph, in 2008. Although larger than Jupiter, it is 1 billion times fainter than the star it orbits.

giant molecular cloud in interstellar space, a mas­sive cloud of mostly hydrogen molecules, sometimes containing enough material to create millions of suns.

Great Silence, the astronomers' term for the com­plete lack of radio signals received from other intel­ligent beings across the galaxy, a puzzle considering how many habitable planets there are likely to be.

heliosheath a region outside the termination shock, where the solar wind slows, thickens, and mixes with interstellar gases.

protoplanet a planet in the process of formation.

protoplanetary debris revolving around a star, a giant ring or cloud of dust and debris from which planets eventually form.

protostar a very dense area of a molecular cloud, where a star is in the process of forming.

termination shock a region outside the solar system where outer space begins and the solar wind drops below supersonic speeds, the furthest distance space­craft from Earth have traveled.

astronomy

Drake equation formulated by Dr. Frank Drake in 1960 in preparation for the meeting in Green Bank, West Virginia, that established the search for extra­terrestrial intelligence (SETI) as a scientific discipline. It suggested that a large number of extraterrestrial civilizations would form, but that technological civi­lizations tend to destroy themselves quickly.

Epsilon Eridani harboring a star by the same name, the closest solar system to our own, approximately 62 trillion miles out, and thought to contain a simi­lar system of planets and asteroid belts. It was the fictional location of the planet Vulcan, home to Star Trek's Spock.

chemistry

absolute zero the lowest temperature theoretically possible, -273.15°C or -459.67°F, in which no heat or motion can exist.

absorption the taking in or soaking up of a gas or liquid, by a liquid or a solid.

accelerator a catalyst that starts or speeds up a chemical reaction without itself being changed.

acid a corrosive compound having a pH less than 7.0 and a hydrogen ion activity greater than water.

activator any substance having the ability to increase the action of a catalyst.

additive a substance combined with another to alter its form, consistency, properties, etc.

adsorption the attachment of a layer of gas, liquid, or solid onto the surface of another substance with­out being absorbed.

alkali an ionic salt of an alkali metal or alkaline earth metal element.

alloy a metal containing two or more elements.

amphoteric capable of reacting as either an acid or a base.

anion a negatively charged atom or atom grouping.

anticatalyst a substance that stops or slows a chem­ical reaction, especially by weakening the action of a catalyst.

atmosphere a measure of air pressure, specifically 1 atmosphere is equal to that experienced at sea level.

atom the smallest component of an element.

atomic mass the total number of protons and neu­trons in an atom's nucleus.

atomic number the total number of protons in an element.

atomic symbol on the periodic table, the symbol that corresponds to each element.

atomize to transform a liquid into a fine spray, mist, or aerosol. Also, to nebulize.

Avogadro's number the number of atoms or mol­ecules in one mole or 6.02 x 10²³. Also known as Avogadro constant. See mole.

base the opposite of an acid, a chemical compound with a pH above 7.0; an alkali. Ammonia is a base.

biodegradation the breaking down and transforma­tion of organic substances, usually through the release of enzymes by microorganisms.

buffer solution a solution added to a mixture to maintain pH at a constant level, used in fermentation and other processes.

catalysis through the use of a catalyst, the speeding up of a chemical reaction.

catalyst any substance used to start or speed up a chemical reaction.

cation an atom or atom grouping with a positive charge.

chain reaction a series of chemical reactions, with each change setting up the necessary products for the next.

charcoal a porous substance made from wood, bone, or coconut, used to absorb gases and liquids.

chelation the removal of metal ions from a solution, used in medicine to treat lead or mercury poisoning.

chemist one who studies and works with chemicals to create useful compounds and mixtures, to deter­mine the chemical makeup of materials, or to perform medical testing and research.

chemoluminescence a glow or giving off of light, produced by a chemical reaction.