Describe what is meant by the Big Bang model of the universe.

State two features of the cosmic microwave background (CMB) radiation which are consistent with the Big Bang model.

Determine the distance to the galaxy in Mpc.

Describe how type Ia supernovae could be used to measure the distance to this galaxy.

theory in which all space/time/energy/matter were created at a point/singularity

at enormous temperature

with the volume of the universe increasing ever since or the universe expanding

OWTTE

[2 marks]

CMB has a black-body spectrum

wavelength stretched by expansion

is highly isotropic/homogenous

but has minor anisotropies predicted by BB model

T «= 2.7 K» is close to predicted value

For MP4 and MP5 idea of “prediction” is needed

[2 marks]

\(\frac{v}{c} = z \Rightarrow v = 0.084 \times 3 \times {10^5} = 2.52 \times {10^4}\) «km\(\,\)s^–1»

\(d = \frac{v}{{{H_0}}} = \frac{{2.52 \times {{10}^4}}}{{68}} = 370.6 \approx 370\) «Mpc»

Allow ECF from MP1 to MP2.

[2 marks]

type Ia have a known luminosity/are standard candles

measure apparent brightness

determine distance from d = \(\sqrt {\frac{L}{{4\pi b}}} \)

Must refer to type Ia. Do not accept other methods (parallax, Cepheids)

[3 marks]