- axions
- a type of WIMPs having masses about 10−10 of an electron mass
- Big Bang
- a gigantic explosion that threw out matter a few billion years ago
- black holes
- objects having such large gravitational fields that things can fall in, but nothing, not even light, can escape
- chaos
- word used to describe systems the outcomes of which are extremely sensitive to initial conditions
- complexity
- an emerging field devoted to the study of complex systems
- cosmic microwave background
- the spectrum of microwave radiation of cosmic origin
- cosmological constant
- a theoretical construct intimately related to the expansion and closure of the universe
- cosmological red shift
- the photon wavelength is stretched in transit from the source to the observer because of the expansion of space itself
- cosmology
- the study of the character and evolution of the universe
- critical density
- the density of matter needed to just halt universal expansion
- critical temperature
- the temperature at which and below which a material becomes a superconductor
- dark matter
- indirectly observed non-luminous matter
- electroweak epoch
- the stage before 10−11 back to 10−34 after the Big Bang
- escape velocity
- takeoff velocity when kinetic energy just cancels gravitational potential energy
- event horizon
- the distance from the object at which the escape velocity is exactly the speed of light
- flat (zero curvature) universe
- a universe that is infinite but not curved
- general relativity
- Einstein’s theory thatdescribes all types of relative motion including accelerated motion and the effects of gravity
- gravitational waves
- mass-created distortions in space that propagate at the speed of light and that are predicted by general relativity
- GUT epoch
- the time period from 10−43 to 10−34 after the Big Bang, when Grand Unification Theory, in which all forces except gravity are identical, governed the universe
- Hubble constant
- a central concept in cosmology whose value is determined by taking the slope of a graph of velocity versus distance, obtained from red shift measurements
- inflationary scenario
- the rapid expansion of the universe by an incredible factor of 10−50 for the brief time from 10−35 to about 10−32s
- MACHOs
- massive compact halo objects; microlensing objects of huge mass
- microlensing
- a process in which light from a distant star is focused and the star appears to brighten in a characteristic manner, when a small body (smaller than about 1/1000 the mass of the Sun) passes between us and the star
- negatively curved
- an open universe that expands forever
- neutralinos
- a type of WIMPs having masses several orders of magnitude greater than nucleon masses
- neutrino oscillations
- a process in which any type of neutrino could change spontaneously into any other
- neutron stars
- literally a star composed of neutrons
- positively curved
- a universe that is closed and eventually contracts
- Quantum gravity
- the theory that deals with particle exchange of gravitons as the mechanism for the force
- quasars
- the moderately distant galaxies that emit as much or more energy than a normal galaxy
- Schwarzschild radius
- the radius of the event horizon
- spontaneous symmetry breaking
- the transition from GUT to electroweak where the forces were no longer unified
- Superconductors
- materials with resistivity of zero
- superforce
- hypothetical unified force in TOE epoch
- Superstring theory
- a theory to unify gravity with the other three forces in which the fundamental particles are considered to act like one-dimensional vibrating strings
- thought experiment
- mental analysis of certain carefully and clearly defined situations to develop an idea
- TOE epoch
- before 10−43 after the Big Bang
- WIMPs
- weakly interacting massive particles; chargeless leptons (non-baryonic matter) interacting negligibly with normal matter