Category Archives: science

Conjunction

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[caption id="attachment_19762" align="aligncenter" width="499"]Jupiter and Saturn 21st December 2020 Jupiter (with some moons) and Saturn, 21st December 2020 (click for larger view) [/caption]

But… while the viewing on the 21st (the peak of the conjunction) was perfect, seeing three of the Galilean moons, and the glorious rings of Saturn, very clearly, getting a decent through-the-lens photo was not so trouble-free. I was dissatisfied with the roughs of the photos I got that night, with lots of blurring and aberrations that I felt I should have been able to overcome. So I spent the next day taking the telescope entirely apart, checking everything, and trying to colimate it properly, and testing schemes for better vibration stabilisation of the camera. I was ready for another session of photographing the next night, but it was cloudy, with only about […] Click to continue reading this post →

Winds of Change!

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[caption id="attachment_19735" align="aligncenter" width="499"]Montage of broken telescope parts Broken Telescope![/caption]There’s an exciting astronomical conjunction tonight! Jupiter and Saturn (that you may have noticed have been approaching each other in the sky steadily over the course of the year) will be at their closest approach! It has already been a lovely sight in the evening sky over the last many days. Since I’d been doing a bit of observation and photography of each planet in July (click on the two below for some blurry (but exciting to me) offerings…see more photos I shared on social media – I don’t think I posted them directly here), I’ve been wondering what sort of views I might be able to […] Click to continue reading this post →

This Feels Great!

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[caption id="attachment_19729" align="aligncenter" width="499"]Andrea Ghez accepting the 2020 nobel prize for physics Andrea Ghez accepting the 2020 Nobel Prize for Physics[/caption]You know, it is easy (and healthy) to be steadfastly cynical about the whole prize thing, but sometimes it is just great to simply cast that aside and get into the spirit of it. This is one such time. The Nobel Prize ceremony was today and you can watch the whole thing on YouTube here. (Physics starts at about 36 minutes in.) My interest was in the moments Andrea Ghez and Roger Penrose picked up (literally this year) their prizes for their wonderful work on black boles. The picture I was able to screen grab of Andrea in particular says it all.

I’ve met Andrea Ghez on an number of occasions (and communicated electronically on many more), usually because of our joint interest in making science accessible to the public through talks (where we first met during K C Cole’s excellent Categorically Not! series), TV shows (where we’ve sometimes connected behind the scenes, in the context of shows or films we’re both in, or thinking of being in), and so forth. All our interactions have been […] Click to continue reading this post →

The Notebooks

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[caption id="attachment_19724" align="aligncenter" width="499"]A montage of notebooks A montage of some of my notebooks. Click to zoom in![/caption]

This is a quick montage of a selection of my notebooks over the last few years. As you may know, I often carry a little (usually black) notebook with me whenever out and about in the world (in normal circumstances at least). It is useful for jotting down or working through ideas, doing computations of research ideas, writing to-do lists, and -very importantly- it is an especially good means of reminding me to grab a moment to do a sketch. As a result, they’ve become a record of what I’ve been thinking about in certain periods, what I might have seen on the way to work (back when I was sketching faces on the subway), and also an interesting combination of marks on paper that I actually simply like just looking at.

On Thursday I’ll be taking part in a big event at the Getty […] Click to continue reading this post →

It’s Black in Physics Week!

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It is #BlackInPhysics week, and be sure to check out the various special activities at https://blackinphysics.org. It is a joy to see the faces and stories popping up on twitter under #BlackInPhysicsRollCall as physicists around the world introduce themselves. Join in! Share! Use it when people in your department tell … Click to continue reading this post →

Dairy Diary

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Yesterday’s kitchen science experiment was this morning’s breakfast! In explaining to my young son about microorganisms that we live with (in our bodies, and as tools of transformation we deploy in various applications like cuisine) I suddenly remembered trying to make yogurt when I was myself very young (although not … Click to continue reading this post →

Early Career Musings

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Because of a certain movie from earlier this Summer (which I have not yet got around to mentioning here on the blog), I’ve been doing a lot of interviews recently, so sorry in advance for my face showing up in all your media. And I know many will sneer because … Click to continue reading this post →

Shaping the Future of Scientific Conferences

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This year’s big annual flagship conference in String theory, Strings 2020, ended two days ago. It was a massive success, and it was held entirely online. There were more than 2000 registered participants from all around the world, with sessions where a large portion of that number were engaged simultaneously! This conference’s attendance more usually ranges at around 300 – 400, as far as I remember, so this was a spectacular change. The success was made possible by -most importantly- the willingness of many people to take part and engage with each other to a degree that was foreign to most participants, combined with smart and tireless effort by the team of organizers in Cape Town, where the conference was originally going to be held physically. There were excellent talks (selected by the programme committee) and many illuminating discussions.

Due to the pandemic, the conference was originally going to be cancelled (or at least postponed to much later in the year), but organizer Jeff Murugan announced at relatively short notice that they were instead going to attempt to do it online on the original dates, and it is wonderful that so many people around the world engaged, instead of just shrinking away into the Covid-19 gloom.

The other major component of the success is what I want to discuss here. It was the use, sometimes in concert, of tools such as Zoom […] Click to continue reading this post →

Spectral, II

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plot of spectral density of (2,2) JT SupergravityWhat’s that now? You want more physics teases? Ok. That dotted line is a (known) JT gravity Schwarzian spectral density. That red line? It’s the fully quantum corrected result! To all orders in topology and beyond. See my paper that appeared today on the arXiv.

(For experts: The red line is made up of about 2000 points for each of which I know the energy, and the full wave function for an associated problem. Using those I can compute lots of things, to good accuracy. One example is the full non-perturbative spectral form factor, that I showed last post.)

-cvj Click to continue reading this post →

Pausing “Business as Usual”

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This Wednesday (10th June), in support of #BlackLivesMatter and the demonstrations taking part worldwide, there will be a day of action in various parts of academia to simply stop doing “business as usual” while the horrors of what is routinely done to black people at all levels of society continue.

What people choose to do on that day is up to them, but there are suggestions as a number of websites. I encourage you to go there and read what they have to say, and make up your own mind. A good start is the ShutDownStem site, and search under #ShutDownAcademia, #ShutDownSTEM and #Strike4BlackLives on social media for chatter, activity, and more resources. The Particles For Justice group, led by people in or close to my field, have also joined in to lead and encourage, and their site is here, again with lots of suggestions for types of action to get involved in.

Frankly, having seen and heard […] Click to continue reading this post →

Online Teaching Methods

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[caption id="attachment_19517" align="aligncenter" width="499"] Sharing my live virtual chalkboard while online teaching using Zoom (the cable for the iPad is for power only).[/caption]It is an interesting time for all of us right now, whatever our walk of life. For those of us who make our living by standing up in front of people and talking and/or leading discussion (as is the case for teachers, lecturers, and professors of various sorts), there has been a lot of rapid learning of new techniques and workflows as we scramble to keep doing that while also not gathering in groups in classrooms and seminar rooms. I started thinking about this last week (the week of 2nd March), prompted by colleagues in the physics department here at USC, and then tested it out last Friday (6th) live with students from my general relativity class (22 students). But they were in the room so that we could iron out any issues, and get a feel for what worked best. Since then, I gave an online research seminar to the combined Harvard/MIT/USC theoretical physics groups on Wednesday (cancelling my original trip to fly to the East Coast to give it in person), and that worked pretty well.

But the big test was this morning. Giving a two hour lecture to my General Relativity class where we were really not all in the same room, but scattered over the campus and city (and maybe beyond), while being able to maintain a live play-by-play working environment on the board, as opposed to just showing slides. Showing slides (by doing screen-sharing) is great, but for the kind of physics techniques I’m teaching, you need to be able to show how to calculate, and bring the material to life – the old “chalk and talk” that people in other fields tend to frown upon, but which is so essential to learning how to actually *think* and navigate the language of physics, which is in large part the diagrams and equations. This is the big challenge lots of people are worried about with regards going online – how do I do that? (Besides, making a full set of slides for every single lecture you might want to do For the next month or more seems to me like a mammoth task – I’d not want to do that.)

So I’ve arrived at a system that works for me, and I thought I’d share it with those of you who might not yet have found your own solution. Many of the things I will say may well be specific to me and my institution (USC) at some level of detail, but aspects of it will generalize to other situations. Adapt as applies to you.

Do share the link to this page with others if you wish to – I may well update it from time to time with more information.

Here goes:
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