I was sent an interesting link a while ago* that I thought I would share with you. It is a really good discussion about Dark Energy – what do we think it is, why we think it exists, why some think it does not, and how to move forward with the discussion of what is, after all apparently *most* of our universe. It is a panel discussion that was hosted by the Institute for Arts and Ideas (which I *love* the idea of!). The discussion is described on the site as follows:
Dark energy is supposed to make up two-thirds of the universe. But troublingly CERN has yet to find any evidence. Have we got our story of the universe wrong – might dark energy be the aether of our time? Do we need a new account of the universe, or is it too soon for such radical solutions?
The BBC’s Sue Nelson asks Templeton Prize winning cosmologist George Ellis, Cambridge physicist David Tong and mathematician Peter Cameron to seek the invisible.
Ok, the “troublingly CERN has yet to find any evidence” part puzzles me a bit, since nobody’s really expecting CERN to find any evidence of it, in any large scale experiments that I’m aware of (please correct me if I am wrong)… Is the writer of the abstract confusing Dark Energy and Dark Matter? Even then I think it is an odd phrase to lead with, especially if you don’t mention the huge amount of evidence from astronomy in the same footing… but I imagine the abstract was maybe not written by a physicist?
Nevertheless, I strongly recommend it as a thought-provoking discussion, and you can find it embedded below. Do also check out their many other interesting [...] Click to continue reading this post
Longest day of the year? It sure felt like it. I spent about 6 hours of it standing high above the city in the sun talking about physics and astronomy to camera… Super tiring.
It is for a new show I’ll say more about later.
Click to continue reading this post
….Let’s hope it is not equipped with a low-flow shower head though. If you get a chance this evening, find a wide area of sky away from as many lights as you can (it does not have to be perfectly dark, but the darker the better). There is a new meteor shower, the Camelopardalids…. It is new because the comet debris responsible (we’re flying through debris left over from its tail) has not intersected with our orbit before, but things have been changing a bit (apparently due to Jupiter’s gravitational pull) and as a result we’ll go right through it for the first time (as far as records show). It is expected that there’s a good chance that it will be a high event shower, and it has also been said – I forgot where I read this – that the [...] Click to continue reading this post
I learned* that over on the Huffington Post, Christian Ott (Caltech) wrote a piece describing research on modelling stellar explosions using supercomputers. When a star goes supernova, what exactly happens? Capturing the physics that goes on is a very difficult problem to do, and in the article he explains some of the difficulties, and some of the recent progress.
There’s a slide show showing some of the [...] Click to continue reading this post
Yes, you heard me right. Holographic Heat Engines. I was thinking recently about black holes in universes with a cosmological constant and their thermodynamics. I had an idea, it led to another, then another, then some calculations, and then a couple of days of writing, calculating, and thinking… then a day to cool off and think about other things. Then I came back to it, decided it was still exciting as an idea and so tidied it all up as a paper, made some diagrams, tidied some more, and voila! A paper submitted to the arxiv.
I’m sort of pleased with all of it since it allowed me to combine a subject I think is really fun (although often so bleakly dull when presented at undergraduate level) – heat engines – with contemporary research ideas in quantum gravity and high energy physics. So I get to draw some of the cycles in the p-V plane (graph of pressure vs volume) representing the inner workings of engines of particular designs (just like you might have seen long ago in a physics class yourself) and compute their efficiency for doing mechanical work in exchange for some heat you supply. It is fundamental that you can’t do that with 100% efficiency otherwise you’d violate the second law of thermodynamics – that’s why all engines have to have some exhaust in the form of heat, giving an efficiency represented by a quantity that is less than one, where one is 100% efficient. The diagram on the left illustrates the key pieces all engines must have, no matter what working substance you’re using. The details of the design of the engine are what kind of cycle you taking it through and what the properties (“equation of state”) your working substance has. In the case of a car, for example, the working substance is cleverly mixed up with the source of heat – the air/gasoline mix forms a “working substance” that gets expanded and compressed in various ways (in the green bit of the diagram), but the fact that it also burns releasing heat means it is also the source of the heat that comes into the engine (the flow from the red bit) to be (in part) turned to work, and the remainder flowing out to the blue (exhaust). Very clever.
The cool thing here is that I’m using black holes as the working substance for [...] Click to continue reading this post
Did you catch the eclipse last Monday? It was wonderful. Here’s a little snap I took of the progress (taken with an iPad camera precariously through the lens of a telescope, pointing out of a bedroom window, so not the best arrangement). One of the striking things about looking at the progress of it is just how extra three-dimensional the moon seems as the earth’s shadow slowly covers it. It really makes one’s whole mind and body latch on to the three dimensional reality of the sky – you really feel it, as opposed to just knowing it in your head. That’s sort of hard to explain – and you’re not going to see it in any photo anyone can show – so I imagine you are not really sure what I’m getting at if [...] Click to continue reading this post
There is a total eclipse of the moon tonight! It is also at not too inconvenient a time (relatively speaking) if you’re on the West Coast. The eclipse begins at 10:58pm (Pacific) and gets to totality by 12:46am. This is good timing for me since I’d been meaning to set up the telescope and look at the moon recently anyway, and a full moon can be rather bright. Now there’ll be a natural filter in the way, indirectly – the earth!
There’s a special event up at the Griffith Observatory if you are interested in making a party out of it. It starts at 7:00pm and you can see more about the [...] Click to continue reading this post
Thursday’s event at the Natural History Museum went very well. There was a great turnout, and the audience was very enthusiastic. As you can see from the photos*, there were two fierce-looking large dinosaurs in attendance in the audience, but it did not have any effect on the overall time-keeping, and the lectures ran over the allotted time quite a bit.
But people had fun, and the museum staff were very kind and flexible, so that’s ok. I actually learned a lot from Ed Krupp’s talk about the astronomy and astronomical objects along the Silk Road from the Far East to the Middle East especially. Laura Danly gave a talk that was mostly a detailed history the Internet including at least three internet cat videos as illustration (an emphasis that I found unexpected, I’ll admit, since I was expecting more about contemporary astronomy). It was certainly a modern perspective on the Silk Road, as we promised the audience, and it seemed to go down well. The observation opportunity that Laura arranged outside (with the telescopes that were set up in the new gardens) was also well received. Jupiter and its [...] Click to continue reading this post
I’m doing a disturbing amount of speechifyin’ this month. One of the occasions is tomorrow, and is open to the general public. Have you been to the Natural History Museum’s “Traveling the Silk Road” exhibition yet? I went to have a look a couple of days ago and it is rather nice. I recommend it. There are even live silk worms!
I’ve been coorganizing an event as part of their series of lectures that accompanies the event and I am delighted to announce that I have connected two of the most awesome spaces and institutions in the city for this one. The Griffith Observatory will team up with the Natural History Museum for this one, with a lecture and Q+A session, and then (weather permitting) a bit of stargazing in the new gardens! Please spread the word and come along: [...] Click to continue reading this post
I’m actually in hiding and silence for a week. It is Spring Break and I have locked myself away in a seaside town to do some writing, as I did last year. But I must break my silence for a little while. Why? Well there’s been a really great announcement in physics today and while being very happy that it is getting a lot of press attention – and it should since the result is very important and exciting – I’ve been stunned by how confusingly it has been reported in several news reports. So I thought I’d say a few things that might help.
But first, let me acknowledge that there’s a ton of coverage out there and so I don’t need to point to any press articles. I will just point to the press release of the BICEP2 collaboration (yes, that’s what they’re called) here, and urge you once you’ve read that to follow the link within to the wealth of data (images, text, graphs, diagrams) that they provide. It’s fantastically comprehensive, so knock yourself out. The paper is here.
I keep hearing reports saying things like “Scientists have proved the Big Bang”. No. The Big Bang, while an exciting and important result for modern cosmology, is very old news. (You can tell since there’s even a TV comedy named after it.) This is not really about the Big Bang. This is about Inflation, the mechanism that made the universe expand rapidly from super-tiny scales to more macroscopic scales in fractions of a second. (I’ll say more about the super-tiny below).
I also hear (slightly more nuanced) reports about this being the first confirmation of Inflation. That’s a point we can argue about, but I’d say that’s not true either. We’ve had other strong clues that Inflation is correct. One of the key things that pops out of inflation is that it flattens out the curvature of universe a lot, and the various observations that have been made about the Cosmic Microwave Background over the years (the CMB is that radiation left over from when the universe was very young (about 380,000 years old – remember the universe is just under 14 million years old!)) have shown us that the universes is remarkably flat. Another previous exciting result in modern cosmology. Today’s result isn’t the first evidence.
So what is today’s exciting news about then? The clue to the correct [...] Click to continue reading this post
On the one hand it is good to get members of the general public excited about scientific research, and so having some new excitement about something Stephen Hawking said, driven by gushingly written articles in the press and online, can be good. On the other hand, it is annoying that the thrust of the articles are largely that he’s stunned the world again with a brilliant and unlooked-for idea. People just lap this stuff up, unquestioningly. It is actually an old idea (and in fact one that is being mis-reported – see below). One’s instinct is to just say “Welcome, Stephen, we’ve been waiting for you to join us”, or “Come on in, the water’s lovely”, and just move on, but it seems so unfair. The thing that’s most puzzling in all of this is Hawking’s own paper (which is all of two pages of words – a transcript of a talk he gave in August), which makes no reference at all to (for example) Samir Mathur’s work, which has been explicitly saying essentially the same thing for well over a decade, with a very definite proposal for how it might work. That work has hardly been buried in obscurity. Samir and many other people who have liked his idea have been working out the consequences of the proposal in numerous papers for over a decade and reporting on their results at all the main conferences, and even talking to him about it (I note that Samir was in the audience during the August talk and even politely asked the speaker to compare and contrast the similar-sounding proposals). So it is puzzling that you get no hint from the paper’s citations that this is a well-considered and ongoing idea, even if (perhaps) in detail it may pan out differently from other suggestions.
What’s the idea?, you ask. Well, it is not, as you might get from most of the articles (somewhat confusingly), that black holes do not exist. It is that the black hole’s event horizon, thought of as a sharp “point of no return” boundary, may not exist. Instead, it is approximation or shorthand for the complicated physics (of both matter and spacetime) that happens in the vicinity of the black hole. Simply put, the horizon arises in classical solutions to classical (i.e. non-quantum) equations (such as in General Relativity) of gravity. (See an earlier post I did about them here, from which came the illustration [...] Click to continue reading this post
I did not get to read the instructions about the games, but pictured are some cards (apparently from about 1830) for a game set. They have images of stars and planets on them, including one planet called Herschel. This is of course the planet to later be called Uranus. It took a while for the planet’s name to be agreed upon.
These are some of the objects from the Doheny Libary’s collection that will be [...] Click to continue reading this post
Don’t forget that on the USC campus on Friday at 4:00pm, we’ll be kicking off the Collecting the Cosmos event! It will be in the Doheny library, and there’ll be a presentation and discussion first, and then a special opening reception for the exhibition. Be sure to get yourself on the waiting list since there’s some chance that you’ll get in even if you have not RSVPed yet. (The image is from the Visions and Voices event site, and includes parts of the artworks – by artists Victor Raphael and Clayton Spada – to be included in the exhibition, so come along and see.) The event description says, in part: [...] Click to continue reading this post
Many people have been asking me whether the show The Universe on the History Channel and its sister channel H2, (now the longest-running science show on commercial TV in the US) has come to an end, and I’ve not actually known the answer (but have been assuming so). Well, the good news is that there are some new episodes being made! I know this since I was involved in some filming for a few segments on two episodes on Thursday. I spent the lunchtime session talking about novae and supernovae, and the [...] Click to continue reading this post
You’ll recall that I was in New York a short while ago to film some promotional material for a new TV series. It is called Big History, and it will be on History Channel’s H2 channel (and eventually on various international channels, but I’ve no idea which – similar ones to where you find the other show I’ve mentioned a bit, The Universe, I expect).
Rather than be primarily about astronomical and cosmological things, the show will focus each week on one of a list specific items that have affected our history, and take the long view about that item. How long a view? The longest known possible! So take something like Salt, and examine its role in civilization and culture, bringing in historians, anthropologists, etc… and physical scientists to trace that object back to its roots in the early universe… (the big bang, the cores of stars, etc.) Update: For you Breaking Bad fans, note that it’ll be narrated by Bryan Cranston, by the way.
Here’s one of the promo videos:
[…] Click to continue reading this post
I just spotted (a bit late) that Steven Weinberg (one of the giants of my field) has written a piece in the New York Review ofBooks entitled “Physics: What We Do and Don’t Know”. I recommend it. He talks about astronomy, cosmology, particle physics, and by casting his eye over the arc of their recent (intertwined) histories of ideas, experiments and discoveries, tries to put the Standard Models of particle physics and of cosmology into perspective.
The article is […] Click to continue reading this post
[caption id="attachment_14281" align="aligncenter" width="499"] The crowd watching Devo on stage at the Natural History Museum’s 100th Birthday celebration (click for larger view)[/caption]The 100th Birthday party at the Natural History Museum was fantastic! Adam Steltzner’s talk was excellent and it was a pleasure to be the MC and introduce him and run the Q&A. (It was a tall order for me to fill Michael Quick’s shoes, but I gave it a shot.) The audience was really great, and there were several great questions. The wide shot (click for larger view) at the top is a panorama shot of the outdoor concert stage, with Devo just starting their set (GZA of Wu-Tang Clan was on just before). I took it* while standing under the fin whale skeleton that is the centerpiece of the new Otis Booth entryway pavilion that was unveiled just minutes earlier. (See more about that space and other new exhibits here.) Here are a couple of shots (click for larger view) from Adam’s session, where he gave an inspiring talk about the engineering of the landing of the Curiosity Mars rover, with reflections on space exploration in general**:
[caption id="attachment_14261" align="aligncenter" width="300"] Adam Steltzner talking about the Curiosity Mission at the Natural History Museum’s 100th Birthday bash[/caption] [...] Click to continue reading this post
If you’re in town on Sunday 9th June, I strongly recommend coming along to this! The Natural History Museum is having its 100th Birthday celebration with an all day series of events. There’ll be new spaces and exhibits opening, including the new gardens they’ve been building for some time, and so there’s plenty to explore that will be new, and partly outdoors on a (hopefully) lovely day. (See here for an LA Times article on some of the changes.) As the day draws into the evening, there’ll be a real party brewing, with bands, DJs, bars, and so forth (see below). Kicking off the evening part of the proceedings at 6:30pm will be a talk and Q+A with JPL’s Adam Steltzner (of the Mars Curiosity Mission), in a spot hosted by me.
Adam’s a great guy, with lots of interesting things to say and a great sense of [...] Click to continue reading this post
Steinn has a nice post about the sudden ending of the Kepler mission, due to a crucial component failure. As he notes:
“Kepler has discovered almost 3,000 planetary candidates, of which about 100 have been confirmed through a variety of techniques, and, statistically, most of the rest are likely to be real planets.
Kepler has not quite found earth like planets in the habitable zone, yet.
It is heartbreakingly close to doing so.”
Sad to see, especially at a time when science is being hurt so badly by continued [...] Click to continue reading this post
You might recall that last year I gave a talk at TED Youth, in their second year of short TED talks aimed at younger audiences. You’ll recall (see e.g. here and here) I made a special set of slides for it, composed from hundreds of my drawings to make it all in graphic novel style, and somehow trying to do (in 7 minutes!!) what the TED people wanted.
They wanted an explanation of string theory, but when I learned that I was the only person in the event talking about physics, I kind of insisted that (in a year when we’d discovered the Higgs boson especially!) I talk more broadly about the broader quest to understand what the world is made of, leaving a brief mention of string theory at the end as one of the possible next steps being worked on. Well, they’ve now edited it all together and made it into one of the lessons on the TED Ed site, and so you can look at it. Show it to friends, young and old, and remember that it is ok if you don’t get everything that is said… it is meant to invite you to find out more on your own. Also, as you see fit, use the pause button, scroll back, etc… to get the most out of the narrative.
I’m reasonably pleased with the outcome, except for one thing. WHY am I rocking [...] Click to continue reading this post
Well, the day is here. The Planck collaboration has announced a huge amount of results for the consumption of the scientific community and the media today. The Planck satellite looks with unprecedented precision at the very earliest radiation (“cosmic microwave background radiation”, CMB) from the universe when it was very young (a wee, cute 380,000 years old) and helps us deduce many things about what the universe was like then, and what it is like now. Here’s one of the representations of the universe using the new sky mapping Planck did (image courtesy ESA/Planck):
There’s a ton of data, and a raft of papers with analysis and conclusions. And there’s a very nice press release. I recommend looking at it. It is here, and the papers are here. The title of the press release is “Planck reveals an almost perfect Universe”, and some of the excitement is in the “almost” part. A number of anomalies that were hinted at by the previous explorer of the CMB, WMAP, seem to have been confirmed by Planck, and so there are some important things to be understood in order to figure out the origin of the anomalies (if they ultimately turn out to be real physics and not data artefacts). [Update: Andrew Jaffe has two nice posts I recommend. One on the science, and the other on the PR. Jester also has a nice post on the science from a particle physicist's perspective.]
What is the title of my post referring to? Well, the refined measurements have allowed us to update some of the vital statistics of the universe. First, it is a bit older than previous measurements have indicated. The age is now measured as 13.82 billion years. (I’m already updating pages in the draft of my book…) Second, the proportion of ingredients [...] Click to continue reading this post
Today (Tuesday) saw me up at 6:30am to prepare for an 8:00am call time for a shoot on a special episode of – wait for it – Deadliest Space Weather. It is original programming for the Weather channel, and before you dismiss it because of the title, it turns out that it is not a bad idea for exploring various scientific concepts. The first season ended a few weeks ago. I’d not realized it was airing until recently, and actually those recent demos I told you about were used in examinations of planetary conditions on Venus and on Mars. (Two separate episodes.) The idea seems to be to consider what it would be like on earth if the conditions were like those on Venus, or consider what what happen if you went outdoors on Mars.
So you might think it is silly, but if done well, it is actually an opportunity to
explain some science to an audience who might not have been the usual science audience…in which case I’m happy to be on board! In addition to spectacularly showing what happens when sugar and sulphuric acid meet, I got to show how to boil [...] Click to continue reading this post
Back home in the office/studio working on slides for the TEDYouth talk. Spent altogether too much time on telescopes today. Way too much. I estimate that this [...] Click to continue reading this post
It has been quite the busy period the last few days, so much so that one is tempted (but not overwhelmingly) to neglect to take note of wonderful things like the discovery of a planet in the Alpha Centauri system, or the awesomeness of my group of students in my graduate electromagnetism class who all did quite well in the midterm I set them. But I took [...] Click to continue reading this post
Have you heard about the film “Nostalgia for the Light“, by Patricio Guzmán? As you know, one of my main cares in the business of communicating science broadly is having it be mixed up nicely with the rest of the culture (not making it a lecture all the time). This helps reach broader audiences, for a start. In a sense, this looks like a film that is doing that. It seems it was released in 2010, but is appearing on some big screens for the first time this year, in some places. I’ve not seen it, but it is soemthing I intend to see, based on the synopsis alone. I thought I’d mention it to you.
The summary from the Guardian film site says “Drama in which a group of Chilean astronomers’ search for the origins of life is contrasted with local womens’ efforts to find the bodies of loved ones killed by the Pinochet regime.”
There’s a trailer here:[...] Click to continue reading this post
You’ve no doubt heard about some of the images coming from the newly landed Curiosity device on the Martian surface. Above is a 360 degree panorama (from NASA/JPL) assembled from lots of smaller images, showing its surroundings in the [...] Click to continue reading this post
Well, that was exciting! Congratulations to the teams on the Curiosity mission! Look out for some great science to come from this laboratory! -cvj
So, if like many people, you are excited about the (late) weekend landing of Curiosity (the roving Mars Science Laboratory) on Mars, and/or if you want to know more, Kenneth Chang has an article in the New York Times all about it here. (Image right is an artist’s impression done for NASA/JPL.) The sequence of operations that have to go right for Curiosity to, er, stick the landing* is quite amazing, and so let’s all wish them good luck. Have a [...] Click to continue reading this post
I’m guessing that most of you who took pictures during the venus transit on Tuesday (see my modest effort here) did not get something quite as good as the one above. Wow. It is by the JAXA/NASA Hinode craft that is in orbit.
From the site [...] Click to continue reading this post
I set up some simple 10×50 binoculars on my tripod, and after a tiny bit of fiddling, out pops the transit in progress from the other end, projected on to the back of an envelope! (The envelope was helpfully held still by a friend so that I could take the photo.) (Click for larger view.) [...] Click to continue reading this post