(d) cosmology

big bang theory (8.13P / 8.14P)

about 14 billion years ago, the whole universe was in a hot dense place, but exploded !!!!!!! it has been expanding ever since. this is shown by the red-shift of galaxies (see next flashcards) and cosmic microwave background radiation. cmbr can be detected EVERYWHERE in the universe. these are the stretched remains of high energy gamma radiation that would have been produced in the big bang, stretching as the universe expands.

this point is just the doppler effect (8.15P)

blehh

relationship between change in wavelength, reference wavelength, velocity of a galaxy and the speed of light (8.16P)

change in wavelength / reference wavelength = velocity of a galaxy / speed of light

λ - λ_o / λ_o = Δλ / λ_o = v / c

c = 3 × 10⁸

explain red-shift (8.17P / 8.18P)

if we examine the light spectra of distant galaxies, we can see that the wavelengths of the light have become longer. this stretching of waves is called ‘red-shift’, and it tells us that the galaxies producing the light are moving further away from us. the further away a galaxy is, the greater its red-shift, so it is moving away even faster. this supports the big bang theory as it is evidence that the universe is expanding.