Much of undergraduate teaching in physics ends much before the student is exposed to the more contemporary research areas. This is because in a subject like physics the amount of training that is required before the student can even be exposed to these areas is daunting and cannot be done at the undergraduate level. On the other hand, it makes little sense if the students have a degree in physics and not be able to get some picture, however rudimentary, of the breadth and depth of the subject. The idea in these courses is to get the student to grapple with experimental information that we have about the world at these disparate scales, to get an understanding of the ingenuity required in setting up experiments that help us glean these secrets of the universe and to imagine the kind of theoretical modelling that may shed some light on the phenomena. Instead of rigour, a broad-based understanding of the topics: making quick and rough estimates, identifying relevant and irrelevant variables in the problem, arriving at useful approximations, dimensional arguments, order-of-magnitude estimations and qualitative reasoning, all-in all a useful part of the toolkit of physicists, should be the focus of the learning process. In addition to working with textbooks, this course aims to introduce the students to primary material such as original or review papers as well as inform the ​’context’ of these discoveries through historical, analytical or biographical accounts.

In this second of the set of two core courses, we take a look at the current understanding of objects and phenomena of the universe.