Through a Lens Darkly

Richard Massey

Well, yesterday’s colloquium by Caltech’s Richard Massey was a lot of fun, and really excellent. When faculty, postdocs and students are all chatting about it afterwards, you know it went well. This is what a departmental colloquium is supposed to do, and it happens when subject, level of delivery and speaker all come together in just the right way.

When the news about that lovely dark matter result broke some months ago, I got in touch with Richard to find out if he would come and tell us about it. He generously agreed (even though at the time he was swamped by the press and various media appearances), and yesterday was the day. While trying to find information about him for the talk I discovered that he was just graduating from Durham University (as an undergraduate) when I was arriving there in 2000. Small world.

Anyway, go and remind yourself of the result, if you like, by reading the earlier post. From the talk, and from talking privately with Richard, I got the sense that the weak gravitational lensing technique that they use to such dramatic effect (see the nice magnifying glass graphic in the background) is merely at the early stages of a wonderful and rich new window on our universe. He spoke at the end of hopes and prospects for various space and ground based wide field telescopes (currently on the drawing board and beyond) that may be deployed that would be entirely dedicated to gathering data for weak lensing analysis. I’m excited about the many things we’ll learn about our universe as a result.


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6 Responses to Through a Lens Darkly

  1. mollishka says:

    Just a point of terminology: this is weak lensing, not microlensing. Microlensing is the term that’s used for what’s done by stars, such as in our own galaxy for planet detection (and is mainly a change in brightness), but weak lensing is the term that used for the small percent-level shape distortions of galaxies by intervening matter.

  2. Clifford says:

    Of course, you’re absolutely right, and I do know that distinction! I’m not really sure why that term crept into my mind at all yesterday while writing the post. I must be going senile… I’ve changed it in the post. Thanks.


  3. Katie says:

    This was really a great talk – well described and illustrated beatifully. I particularly enjoyed the example of the Bullet cluster, differentiating the effects (or lack thereof) of a collision on dark matter and baryonic matter. Quite illuminating!

  4. Clifford says:

    Hi Katie,


    See the “related links” at the end of this post for posts I did on the Bullet Cluster.


  5. Jeff Nuttall says:

    That was an interesting talk. I wasn’t able to go to any of the colloquia last semester, because I was teaching an evening class at a community college, but this is the third one I’ve been to so far this semester, and I’m feeling better about my ability to actually understand the talks. Last year I was feeling kind of frustrated about the colloquia because it seemed they were always way over my head; I could only grasp a few threads of what the speaker was saying, and the rest was gibberish. So far in the colloquia I’ve attended this semester, I haven’t had that problem; I’ve been able to follow the concepts in the talks pretty easily. I’m not sure why the difference; certainly I don’t think my general knowledge of physics has increased that much over the last year…

  6. Clifford says:

    You are getting more mature Jeff. Others just give up, and never get to the point you just described. This is part of what colloquia are for….

    I’m pleased to hear this.