What Can The CMB Tell Us? – Part I

So it turns out that last week’s choice of the CMB as a topic was a particularly presient one, as this week’s science news is dominated with a story that has a lot to do with these all-important photons. If it proves to hold up to scrutiny, BICEPs detection of B-Mode gravitational waves may be the biggest physics story of the year. It has implications for theories of inflation, the big bang and even quantum gravity. It even may be the first sign on our roadmap to a “grand unified theory”, and it all comes from the Cosmic Microwave Background!
As promised, this week I will be explaining how and what we measure when we look at the CMB, and what that can tell us about the history of our universe and what we can discover about the universe we live in today. However, the idea behind this blog is to cover The Interesting Part of the science stories making the headlines, and the fact is that The Interesting Part of BICEPs potential discovery is… well… all of it! So in the next couple of days I’m also going to try and write some bonus posts on topics such as Gravitational Waves, Inflation and Energy Scales, to try and get to the heart of why BICEPs results have the potential to be so important.

For more information of BICEPs results see here and here, and for analysis of what it means and why we shouldn’t get TOO excited about it yet, see here and here. Now, on with the CMB!

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What is the Cosmic Microwave Background?

Hello and welcome to the first installment of “The Interesting Part”, a weekly blog where I look in a little more depth at the Interesting Part (to my mind) of some of the week’s science news.

     For my first week, I thought I’d go a little easy on myself and pick something I already have some knowledge about. It just so happens that a topic fitting this description found its way into three different articles that I came across this week. Firstly, this article from Ars Technica talking about the so-called “cosmological axis of evil” first discussed in a 2005 paper based on WMAP data. My topic also appears in this New Scientist article from last month discussing the “mysteries” of the big bang (warning, requires subscription) and in Annalee Newitz’ piece for Slate, republished in this week’s National Post about a Avi Loeb’s suggestion of a “habitable epoch” in the early universe. The thread that ties these together? The Cosmic Microwave Background or CMB, a faint light that permeates the entire known universe, which originated before galaxies, planets or even stars began to form.

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