Friday, April 22, 2011...11:42 pm

Open University science update: things get tougher

Jump to Comments

Regular readers may be aware that Freelance Unbound is a hotbed of scientific endeavour, as I am doing an OU science degree in my spare time.

Posting has been even lighter than usual recently, and readers may be interested in the reason:

Question 8.4

The spectrum of light from a distant galaxy contains absorption lines that are identified as being due to hydrogen atoms. A particular line is observed at a wavelength of 500.7 nm, compared with the wavelength of 486.1 nm that would be produced by a source at rest in the laboratory.

(a) Is the galaxy receding from or approaching the Earth?

(b) What is the value of the redshift or blueshift for the galaxy?

(c) What is the apparent speed of the galaxy with respect to the Earth? (You may assume the speed of light is 3.0 x 105 km s-1.)

Yes – unit S104 Exploring Science has become a bit more challenging than the basic rain gauge experiment that I made a hash of only a few short months ago. We’re into the Hubble constant, Z bosons and quantised energy – and still only year 1.

This is actually great stuff. Undergraduates – don’t waste £9000 a year going to some former polytechnic to take your degree, get real VFM from the OU!

It’s not a soft option – this is challenging material. The only drawback with distance learning is the temptation not to learn stuff by heart, but to refer to the books too much when you’re writing your assignments. The lack of exam-condition testing does mean you need more self-discipline.

Answers
Obviously the galaxy is receding from the Earth (galaxies generally are), so it is redshifted. The value of the redshift is 0.0300 (to three significant figures), and the galaxy’s apparent speed is 9.0 x 103 km s-1 (2SF).

Astonishingly, I even got this right. Roll on year 2…

4 Comments

  • I admire you enormously for doing this Freelance. I attempted an OU degree course myself a couple of years ago and I just couldn’t manage the amount of work on top of all the other things I do. I enjoyed what I did manage to complete enormously and I understand your desire to learn about Science. I find it interesting that many scientists have a passion for the arts in some capacity, whereas few arts people have a passion for science.

  • The OU is a bit of an eye-opener, isn’t it?
    After bailing out of chasing news stories around the globe for a living, I decided, on a whim, to become a mathematician.
    Only a PhD, an MSc and a BSc stood in the way.
    With trusty new, and local, McJob to hand and 30 hours a week to dedicate to study, I started at level one with the OU, then promptly remembered why I hadn’t originally gone to uni (save a short NCTJ stint at Sheffield Hallam) nearly 20 years earlier – it’s bloody hard work.
    Maths, in journalism, had reached the heady heights of currency conversion and negotiating Spanish hire car rates – in English.
    Suddenly, I was being assaulted by calculus. And more.
    Now, after nearly three years of pulling faces at differential equations, blancmange functions, eigenstuff and assignments, I’m 2/3rds the way to leaping hurdle one – the BSc.
    The MSc will follow in 2013.
    Good luck with your studies, calculus, precipitation experiments and boxes of rocks.
    Having only just found this blog, I’m looking forward to frequent revisits to enjoy your elucidations expounding upon the merits of studying with the OU.

  • Freelance UnboundNo Gravatar
    April 30th, 2011 at 11:37 pm

    Welcome, OUmaths

    I’ve not talked about the OU work as much as I thought I would, but I plan to devote some more time to it in future.

    Good luck with the maths – my next unit is mathematics, and I can’t tell you how much I’m dreading the calculus! But as I’m aiming to tackle quantum physics in year 3, there’s no alternative!

  • Calculus is a bit like photography – expert practitioners often declare it to be a mystic art that only the chosen ones can master.
    In all honesty, it’s one of the easier things to get the hang of in mathematics since you use it so much it becomes an automated process – much like demystifying photography by figuring out depth of field, shutter speed and ASA rating [I come from a pre-digital era :-)] and, lo and behold, with a bit of practice, a photo to flog to the DT.
    Don’t let it put you off.
    Reading this blog gives me a hankering to quit the McJob and go back to doorstepping celebrities in St John’s Wood, by the way. :-0
    Keep up the good work.
    oumaths recently posted..A lot of videos containing similar maths to MST209 unit 12

WordPress SEO
Login