Observational Cosmology - Assessed Exercise 1
The Age of the Universe
(a) Using sketches of a(t) and (for simple cases) equations, show how the age of the Universe compares with the Hubble time in cosmologies with high and low matter density (you may ignore radiation) (i) without and (ii) with a positive cosmological constant.
(b) Taking the Hubble constant to be 72 km/s/Mpc, compare the results from part (a) with observational constraints on the age of the Universe. Which cosmologies can be ruled out by such a comparison?
You are expected to spend about 4 hours on this assignment, which accounts for 10% of the credit for the course. In order to help prevent the time you spend from inflating, a strict length limit will be imposed. Your submission must not exceed two sides of A4, at a font size no smaller than 10pt if word processed. Any overflow beyond this will be discounted.
The assessment of this assignment will be split equally between
parts (a.i), (a.ii) and (b), with an additional component for the
clarity and comprehensibility of your script. This may sound obvious,
but do ensure that you actually
answer the question! For example, in part (b) you will need to
look into the observational constraints on the age of the Universe, so
you can compare them with your results from part (a).
Please note that scripts cannot be returned to you after marking (though, of course, the marks will be, and I will also provide feedback on some of the most common errors I encounter) - you may therefore want to keep a copy of what you submit.
A word of warning
You are encouraged to discuss this assigment with others on the course - this is an excellent way of testing and sharpening your understanding. However, it is essential that the work you submit is your own.
Send comments or suggestions on these pages to Trevor Ponman.
Last updated 15 Oct. 2008