“Let us examine for a moment the current all-encompassing science of cosmology.... The big bang theory proclaims that the whole universe created itself instantly out of nothing. I believe there are many observations by now that disprove this...” (astrophysicist Halton Arp, 2000, 14:448).
[NOTE: Words and phrases in bold type within these definitions also appear in the glossary.]
Absolute Zero—The theoretical temperature at which substances possess no thermal energy and all molecular motion ceases. Equal to 0 Kelvin, -273.15° Celsius, or -459.67° Fahrenheit.
Anisotropy—From Greek anisos, meaning “unequal”; having properties that vary according to the direction of measurement; opposite of isotropy.
Axions—Theoretical particles that have no charge or spin, and an extremely small mass. They have been proposed to explain unknown characteristics of the strong nuclear force.
Baryonic Matter—All conventional (“normal”) matter comprised of protons and neutrons.
“Big Chill”—Cosmological theory which suggests that the Universe will accelerate its expansion, growing increasingly cold with its infinite advance.
“Big Crunch”—Cosmological theory which suggests that the Universe expanded originally from a singularity, eventually will collapse back again, and will repeat such a cycle indefinitely.
Black Hole—A theoretical object whose mass is at such an intense density that the escape velocity exceeds the speed of light, thus preventing even light from exiting.
Cosmic Microwave Background Radiation (CMB)—An observed cosmic radiation on the order of microwaves [waves that have the shortest wavelength in the radio wave spectrum] emanating from space, independent of directional measurements.
Cosmological Redshift—The “apparent movement” of matter in space, caused by the movement of space itself rather than the motion of matter itself; also known as Hubble flow or expansion redshift.
Cosmology—From Greek kosmos, meaning “order”; the study of the Cosmos (i.e., the ordered Universe) in all its aspects.
Dark Energy—Theoretical “missing energy” that has been suggested to account for a deficiency in the Big Bang Theory and its variants; hypothesized, but not yet documented to exist.
Dark Matter—Theoretical particles that emit little or no detectable radiation of their own, and that are postulated to exist because of the effects of gravitational forces on other astronomical objects; hypothesized, but not yet documented to exist.
Doppler Effect—The change in the observed frequency of an electromagnetic wave due to the relative motion of source and/or observer.
Entropy—Measure of the disorder or randomness in a system; the portion of heat (energy) content unavailable to perform work.
Expansion—The concept in astronomy which suggests that the distance between galaxies in the Universe is continually increasing in size (which means that galaxies outside our own are receding from us).
Expansion Redshift—The “apparent movement” of matter in space caused by the movement of space itself rather than the motion of matter; also known as Hubble flow or cosmological redshift.
First Law of Thermodynamics—The scientific law which states that neither matter nor energy can be created or destroyed in a closed system, but can only be conserved.
Galaxy—Large-scale collection of stars, gas, and debris. The Milky Way Galaxy, where Earth resides, is classified as a spiral galaxy.
Globular Cluster—A group of many thousands of stars, which are traveling through space together and that are much closer to each other than the stars around the group.
Gravitational Redshift—The movement of matter in space caused, not by the expansion of space around the matter, but by gravitational forces that actually cause the matter itself to move (cf. Hubble flow/cosmological redshift/expansion redshift).
Homogeneity—The concept which suggests that matter is distributed uniformly throughout the Universe.
Hubble Constant—The scientific constant of proportion between relative velocity and distance that is used to calculate the expansion rate of the Universe.
Hubble Flow—The “apparent movement” of matter in space, caused by the movement of space itself rather than the motion of matter itself; also known as cosmological redshift or expansion redshift.
Inflation—Rapid expansion of the Universe, required for the Inflationary Big Bang Hypothesis.
Inflaton—Theoretical particle whose sole purpose is to provide the vacuum of space with the required energy to produce inflation.
Irtrons—Theoretical points that spontaneously produce hydrogen from nothing and spew it into the Universe; hypothesized in an attempt to maintain a steady-state type of Universe.
Isotropy—From Greek isos meaning “equal”; having identical properties in all directions.
Light-years—A unit of measurement of astronomical distance; the distance that light travels in a vacuum in one year (approximately 5.88 trillion miles). [Distances expressed in light-years represent the time that light would take to cross that distance.]
Nebula—A diffuse mass of interstellar dust or gas or both, visible as luminous patches.
Nucleosynthesis—The creation of the elements via nuclear reactions; theoretically, the process by which heavier chemical elements are manufactured from hydrogen nuclei.
Quasars—Quasi-Stellar Astronomical Objects. Originally, these objects were called “quasi-stellar radio sources” (“quasars” for short). Quasars are compact, extragalactic objects that look like points of light, but which emit more energy (mostly as infrared radiation) than a hundred supergiant galaxies. Considered to be the most distant and youngest objects in the Universe.
Redshift—An increase in the wavelength of radiation emitted by a celestial body; often considered to be the consequence of the Doppler effect.
Second Law of Thermodynamics—Also known as the “Law of Increasing Entropy”; basically, the Second Law says three things: (a) systems will tend toward the most probable state; (b) systems will tend toward the most random state, and (c) systems will increase in entropy, where entropy is a measure of the unavailability of energy to do useful work.
Steady State Theory—Cosmological theory which proposed the spontaneous generation of hydrogen from nothing at hypothetical points known as “irtrons,” thereby causing the Universe to expand forever and thus remain in a “steady state.”
Sunyaev-Zeldovich Effect—The thermal effect arising from the frequency shift when cosmic microwave background radiation is scattered by the hot electrons in interstellar gas.
Superclusters—A large group of neighboring clusters of galaxies.
Universe—All matter and energy, including the Earth, the galaxies, and the contents of intergalactic space, regarded as a whole.
Vortices—The swirling or circular motion, tending to form a cavity or vacuum at its center.
Ylem—The hypothetical primordial matter, which according to the Big Bang, existed prior to the formation of the elements. Sometimes referred to as the “cosmic egg,” it is the alleged seed that contained all the matter in the known Universe.