1. 2014

    BICEP2 and the primordial B-modes

    Yesterday the BICEP2 experiment (Wikipedia page) announced a result that physicists and astronomers around the world had been positively drooling over for two days: the detection of primordial B-modes in the cosmic microwave background.

    Ordinarily I would write a whole blog post going through the BICEP2 paper: what the experiment is, what they’re looking for in the cosmic microwave background, what exactly they found, and why you should be excited about it too, but right now I’m super-busy with other things (including another blog post slated for later this week). So instead I leave you with this collection of links to peruse:

    Background info:

    Reports of the results:

    Popular articles:

    There are many others, of course, but that should be enough to get you started. Also follow the #BICEP2 hashtag on Twitter.

    I leave you …

  2. 2013

    An April Fool's Planck, for science

    Oh, I kid. Despite the name, nothing about this post is a prank (except perhaps for the title).

    It’s been a week and a half since the Planck collaboration released their measurements of the cosmic microwave background. At the time, I wrote about some of the many other places you can read about what those measurements mean for cosmology and particle physics. But it’s a little harder to find information on how we come to those conclusions. So I thought I’d dig into the science behind the cosmic microwave background: how we measure it and how we manipulate those measurements to come up with numbers.

    Measuring the CMB

    With that in mind, what did Planck actually measure? Well, the satellite is basically a spectrometer attached to a telescope. It has 74 individual detectors, each of which detects photons in one of 9 separate frequency ranges. As the telescope points in a certain direction, each detector records how much energy carried by photons in its frequency range hit it from that direction. The data collected would look something like the points in this plot:

    From any one of these data points, given the frequency and the measured power …

  3. 2013

    Planck exposes the universe

    Yesterday, the team behind the European Space Agency’s Planck satellite released their first set of data. This was a seriously exciting moment in the world of cosmology, in the same way as the previous weeks’ Higgs updates were an exciting moment in the world of particle physics. And I have the perfect way to explain it to you:

    Go read this, this, this, this, and this.

    OK, seriously though. The preceding five blog posts do a fantastic job (individually, and even more so together) of explaining, at a reasonably abstract level why the Planck data release is important and what it means. Now, I do plan to do my usual act of digging into the science and explaining some of the details, but in this case, there’s a lot of science. The Planck collaboration released thirty papers, and I just haven’t had time to comb through them yet. So a proper Planck post will have to wait for some time later this weekend. Until then, you can get a good, just-technical-enough overview of results from Ethan Siegel’s summary post, the last link in that last paragraph.