unit 1 quiz Flashcards
big bang
leading theory of how the universe originated
hypothesis
an educated guess based on observations
can be supported or rejected but cannot be proven
explains the why
theory
summarizes a hypothesis that explains a set of observations
supported by testing
explains the why
law
governs a body of observations with no exceptions
describes observations
how they happen
scientific method
observations, hypothesis, testing, theory, law
singularity
an area in space-time where the gravitational force is so high that all known laws of physics break down
gigantic expansion
needs space to expand
3 pillars of proof
the recession of stars/galaxy (as described by Hubble’s law)
characteristics of cosmic microwave background radiation
the abundance of light elements
Hubble
1889-1953
demonstrated that there were other galaxies
proved the universe was expanding
showed us how to measure the distance in space
fought to have astronomy apart of the subject of physics
doppler effect/shift
when an object coming towards you makes a sound, the sound waves are compressed by the motion of the noisy object and sounds different to you than when the same sound waves are being carried off away form you
redshift
can be used as a measure of a star/galaxies distance from earth
Hubble’s’ law
v=Hod
v=speed km/s
d=distance of the star/galaxy away from earth in parsecs
Ho= Hubble constant = speed of expansion of the universe
characteristics of cosmic microwave background radiation
the original heat from the bb (hot light photons) have lost energy and dropped from visible light to microwave energy range and the cmb that we can still see
cmb
can be seen from anywhere in the universe bc it comes from all directions with the same intensity
the abundance of light elements
the ratio of all the various atoms of the 3 lightest elements
h 75
he 25
li trace
can only be explained if they all originated from 1 single ratio of the first subatomic particles and matter that was formed in the hot bb
