My poorly-shopped title image :(

RANDOM MEANDERINGS THROUGH THE COSMIC WEB


Theoretical Astrophysics and The C.M.B.


I work at the Institute of Astronomy on Madingley Road in Cambridge, UK. I'm studying for a PhD (Philosophae Doctorum) which should take me about three and a half years. I have to get it done in this time because my funding will run out then, and I won't be able to afford such luxuries as lights and warmth.


I work on something called the Cosmic Microwave Background (CMB) which isn't actually quite as complicated as it sounds. An easy way to think about it is that it's the 'hissing' noise left over from when the universe exploded into existence 14.5 billion years ago. Here's what it looks like:

CMB-round

If we 'unfold' this ball onto a flat surface, then we get an image that looks something like this:

CMB flat

Now the interesting thing about this is that it's not the same everywhere. If the universe exploded into life from a primordial singularity, then any tiny fluctuations in the initial universe would have been amplified by the colossal expansion in the first fraction of a second after the hot big bang. It's worth pointing out that the difference between the red (hot) areas and the blue (cold) areas on these images is absolutely tiny, miniscule even. Something of the order of 1 part in 105. This glow is strongest in the microwave region of the radio spectrum, hence the name cosmic microwave background radiation.

The CMB's discovery in 1964 by radio astronomers Arno Penzias and Robert Wilson earned them the 1978 Nobel Prize. By looking at this pattern in more detail, cosmologists (I suppose I'm now a cosmologist, wow that sounds scary...) can work out what the initial conditions were like at the moment just after creation of the universe. There's a problem though. We've probed the data as much as possible and can't really make any new discoveries until we get better glasses with which to observe the CMB. It's like trying to make out the detail in a really fuzzy TV picture, you can sort of see what's going on, but you're not completely sure. Then you upgrade to a HD TV and see everything in really fine detail. That's what the Planck Satellite was designed for. It's like upgrading our telescope to HD, except that it's not a telescope it's a satellite, and it's not on Earth it's a very very long way away at the L2 Lagrange point. This image shows how much of a difference Planck will make to our 'reception':

CMB resolution

I work on a small area of the field, but nonetheless an important one. To understand what I work on we need to look at a particular type of radiation from the CMB....polarised light.