11B.4 The Age Of The Universe Flashcards
what is red shift
the apparent change in wavelength of a star’s spectrum, caused by the increasing separation between the star and earth
what is Doppler’s effect
the effect that an observer who is receiving waves emitted from a moving body observes that the wavelength of the waves has been altered, to a new wavelength, as a consequence of the relative motion
if a galaxy or a star has red shift it shows that
it is travelling away from us because its wavelength has been stretched
if a galaxy or a star has a blue shift it shows that
it is travelling towards us as the wavelengths are compressed
what is the formula to calculate the amount of red shift a galaxy exhibits, z,
z = dΛ/Λ = df/f = v/c
what is Hubble’s law
the recession velocity of a galaxy is directly proportional to the distance to it
according to Hubble’s law recession velocity is equal to
v = Ho d
what is Hubble’s constant
the constant of proportionality in Hubble’s law Ho = 70.9 km/s Mpc
how can we determine Ho
plotting a stars recession velocity against the distance to it, and the gradient is equal to Ho
what is the expression for the To (age of the universe)
To =1/Ho (how to get their is page 195)
what is big bang theory
the theory that the universe expanded outwards. from the single point to the currently observed situation
what is rescission velocity
the speed at which one object is moving away from another object
