| Date | May 2014 | Marks available | 3 | Reference code | 14M.3.HL.TZ1.4 |
| Level | Higher level | Paper | Paper 3 | Time zone | Time zone 1 |
| Command term | Explain and State | Question number | 4 | Adapted from | N/A |
Question
This question is about the structure of the universe.
(i) State, in terms of the arrangement of galaxies, the present large-scale distribution of mass in the universe.
(ii) State how the separation of distant galaxies is changing with time.
State and explain the observational evidence for your answer to (a)(ii).
Markscheme
(i) galaxies arranged in clusters (that are themselves arranged in superclusters);
(ii) galaxies/clusters/superclusters move further apart / distance between galaxies/ clusters/superclusters increases;
increase in wavelength / red-shift is observed in light from distant galaxies;
the red-shift increases with distance;
therefore (the metric of) space is expanding (with time) / the separation between galaxies is increasing;
following the Big Bang;
Galaxies are moving away from us or from Earth is not enough for the third mark.
Do not award mark for background radiation.
Examiners report
Candidates generally understood the distribution of galaxies in the universe and could clearly explain red-shift.
Candidates generally understood the distribution of galaxies in the universe and could clearly explain red-shift.
