78-82

matter that has mass but doesn't emit light

plot of orbital velocity of the stars and gas moving around it at each distance from its center

focuses light from behind it, making background objects look brighter

massive compact halo object

weakly interacting massive particles

study of structure and evolution of universe as a whole

when the universe was created through a hot dense violent state of matter and energy

universe looks the same to all observers, no matter where they are located in.

stretching

expansion of space, gathering into clusters, galaxies, and solar systems.

rate proportional to their separation.

13.7 billion years ago

recession of one galaxy from another galaxy

argument that sky should be a bright night because a combined light from all distant stars and galaxies

the max distance light can travel in the universe's age

the space between the cosmic horizon

radiation created during the big bang that permeates space

2.73

bending of space leading to finite volume

with positive curvature is analogous to surface of a sphere

form of curved space described as being open because it has no boundary.

universe that extends forever with no curvature. total energy is zero

time when matter and radiation behaved almost as a single entity

type of matter that brought into contact with ordinary matter annihilates it leaving nothing but energy

antimatter partner of the electron

the antimatter partner of the electron

when the universe would have been packed into volume far smaller than a proton and the temp greater than 10^33 Kelvin

where particles flash in and out of existence and changes occur according to probablities

an enormous expansion of early universe

seperate universes

the strength of gravity and the upward impulse given to it

the universe will expand forever

critical density or rho as pc

quanitity indicitaing how close the observed density is to the critical density.

universe recollapse

universe expands forever

universe at critical density.

a crushing existing from an overwhelming force of gravity that all objects and atoms with be compressed to higher densities.

a term in equations describes effects of gravity on the entire universe, a repulsive force opposing gravity

dark energy

energy detected by effect on expansion of the universe

expansion to speed up

the universe expands so fast that every part of the universe is pulled away from other parts at high speeds they disappear from each other

speed of a thrown object depends on how fast and in what direction thrower is moving

classically

when time stretches, length

contracts in the direction of motion

matter contracts while it moves, reducing length in direction while it moves, reducing length in direction of motion

velocity necessary to avoid being gravitationally pulled back to an object

theory of gravitation that shows space and time communicate the gravitational force through their curvature

being stationary in a gravitational field is equivalent to being accelerated field is equivalent to being accelerated in a constant acceleration frame of reference.

compressed single point in a black hole

boundary around black hole that light nor radiation can escape

a compressed stellar core with a small radius where nothing can escape

it will not stop collapsing

escape is impossible

photons traveling away from a massive object. light moving away loses energy

stretch matter out into longer and thinner strands

not like a solid disk, inner rotates faster then outer.

tendency of an object to stay in a constant state of rest or uniform motion

False

Increase

hydrogen

same side of the moon always faces the earth

opposition

wanderer

less than the average density of the inner planets