Since the early Summer I’ve been working (with the help of several people at USC*) toward a big event next Friday: A celebration of 100 years since Einstein formulated the field equations of General Relativity, a theory which is one of the top one or few (depending upon who you argue with over beers about this) scientific achievements in the history of human thought. The event is a collaboration between the USC Harman Academy of Polymathic Study and the LAIH, which I co-direct. I chose the title of this post since (putting aside the obvious desire to resonate with a certain great work of literature) this remarkable scientific framework has proven to be a remarkably robust and accurate model of how our universe’s gravity actually works in every area it has been tested with experiment and observation**. Despite being all about bizarre things like warped spacetime, slowing down time, and so forth, which most people think is to do only with science fiction. (And yes, you probably test it every day through your […] Click to continue reading this post
Had to nip over to Joshua Tree National Park yesterday, for my sins.
Why? Well, gravity, of course. I can’t tell you the full details, but I was helping out the folks from the BBC on a documentary program (for the series Horizon, which I loved watching back in the 80s when I was in school!) being made about topics connected to gravity, space travel, mass, energy, and all that good stuff.
You can see me mid-demo in the photo (click for larger view), standing upon a rock somewhere in the park, talking about Newton and Einstein. I also got to be a bit of a stunt driver for a while, being filmed bouncing an SUV along a dirt road several times, which was (I grudgingly admit) a lot of fun!
After the shoot […] Click to continue reading this post
As promised, the Screen Junkies episode we made is out. It is about The Martian! JPL’s Christina Heinlein (a planetary science expert) also took part, and I hope you find it interesting and thought-provoking. Maybe even funny too! As usual, there’s a lot that was said that was inevitably left on the (virtual) cutting-room floor, but a lot of good stuff made the cut. All in all, I’d say that this film (which I enjoyed a lot!) had a refreshing take on science and engineering for a big studio film, on several scores. (Remaining sentences are spoiler-free.) First, rather than hiding the slow machinations involved in problem-solving, it has a lot of it up front! It’s an actual celebration of problem-solving, part of the heart and soul of science and engineering. Second, rather than have the standard nerd stereotype […] Click to continue reading this post
Yes, I’ve been hanging out with my Screen Junkies friends again, and this time I also got to meet JPL’s Christina Heinlein, who you may recall was in the first of the Screen Junkies “Movie Science” episodes last year. While we were both in it, I’d not got to meet her that time since our chats with host Hal Rudnick were recorded at quite different times. This time, however, schedules meant […] Click to continue reading this post
(Click for larger view.) This was a heartening reminder that people still care about what’s going on in the sky far above. This is a snap I took of a very long line of people (along the block and then around the corner and then some more) waiting for the shuttle bus to the Griffith Observatory to take part in the moon viewing activities up there tonight. (I took it at about 6:00pm, so I hope they all made it up in time!) The full moon is at close approach, and there was a total lunar eclipse as well. Knowing the people at the Observatory, I imagine they had arranged for lots of telescopes to be out on the lawn in front of the Observatory itself, as well as plenty of people on hand to explain things to curious visitors.
I hope you got to see some of the eclipse! (It is just coming off peak now as I type…)
-cvj Click to continue reading this post
Here, as promised yesterday, is the fun conversation at Screen Junkies. I don’t need to say much, since much of what I wanted to talk about (extra dimensions, other laws of physics, parallel universes, etc) made it to the (awesomely cut, btw!) episode! Embed of video below.
Enjoy! […] Click to continue reading this post
No expense spared on astronomy graphics here, you’ll notice. (This is the Pluto-less hanging mobile that amuses my son every morning when he wakes up. At least I think it is supposed to represent our Solar system in some vague way… in any case, it is a very pleasant object to look at for both him and me.)
Just in case you’ve not been following the exciting news, let me remind you to look out for the new information arriving from the New Horizons mission to Pluto. The craft has done its closest approach now, and later tonight will start sending the best of the images and other data about the Pluto system. A huge amount has been learned already in the days leading up to today, as you can get a sense of by looking here. Earlier today, the lovely image to the right (credit: NASA/APL/SwRI – click for larger view) […] Click to continue reading this post
Yeah. Not sure how to best title this post or fully explain the picture [edit: Picture taken down temporarily until the show is ready to be promoted]. Let’s just say that I spent a bit of this afternoon explaining some of the science of the Large Hadron Collider to a bright orange puppet that was determined to not believe whatever I told him/it. It was fun, and was done to camera at Los Angeles Center Studios downtown. (I was actually speaking about things that intersect with the subject of yesterday’s post, if you’re interested.) It is for a new show on a channel that I can’t mention yet*, and I’ll let you know as soon as I know what the air date is, etc.
Well, one more thing, in support of the old “It’s a small world after all” saying. I noticed from the call sheet that this morning they were shooting a fun segment that was hosted by my friend Hal Rudnick the host of Screen Junkies! (Have a look at some of the science-meets-movies things we’ve done together here, here and here.) Also, a friend I’d not seen in […] Click to continue reading this post
So, here we are. Still in existence. Hurrah!
The Large Hadron Collider (image right is courtesy of CERN) started a new phase of experimental work today, colliding particles at double the energy it was working at a few years back when the Higgs was discovered. By time I was making breakfast and checking email, their live blog, etc., this morning, it was clear that (contrary to fears expressed by some) the LHC had not created a black hole that swallowed the earth, nor had it created some sort of strange chunk of new vacuum that condensed that of the entire universe into a new phase. (Or if it did either of those things, the effects are hardly noticeable!!)
As I keep emphasising (actually I’ll be talking about this to a puppet character on a TV show tomorrow too – details later) the LHC (or any of the particle collision experiments we’ve ever done) is not doing anything that Nature does not do routinely right here at earth (and most times way more violently and […] Click to continue reading this post
Recall that some years ago the Hubble telescope found a rude message in the sky:
It is said that many were offended by this sign. Some even thought it may have been left by their God as a sort of crude final message for those seeking meaning in the skies. Other, perhaps less imaginative people just figured it’s a random combination of shapes people are projecting onto.
Well, after much more searching through the sky for the perpetrator of the crime, it seems that the Hubble instrument may have caught a suspect on camera:
Of course, until the entity is brought in for questioning, it should be granted the presumption of innocence. (And even if it was its hand, it may have all been a big celestial misunderstanding…)
P.S. The first NASA/ESA Hubble image is from a detail of gas clouds in the Carina nebula, and more can be found out about it here.
In the second NASA/ESA Hubble image the arcs of a circle that form the “head” shape are actually a gravitational lensing effect. 100 years ago this year Einstein published his General Relativity which shows, among other things, […] Click to continue reading this post
…Or at least, not always the fire you’re looking for. So, as suspected for several months now, the signal seen by BICEP2 experiment and dubbed “a smoking gun” type of direct evidence for cosmic inflation (for which we have lots of strongly suggestive indirect evidence, by the way) is likely an artefact of the effects of galactic dust. I spoke about this in a post a while back, so I won’t repeat myself here. What everyone has been waiting for has been the results of a joint analysis between the BICEP2 people and the ESA’s Planck mission. The Planck satellite, you may recall from reading here or elsewhere, is also designed to carefully study the polarisation of the cosmic microwave background (the earliest light to shine in the universe), and so can (through thorough analysis of the effects of dust that it has measured independently) help rule in or out whether there is a signal. Planck studies essentially the whole sky, not just the patch that BICEP2 was carefully looking at, and one of […] Click to continue reading this post
Here is a page of a lovely set of (public domain) images of comets and meteors, as depicted in various ways through the centuries. The above sample is from the famous […] Click to continue reading this post
As promised on Tuesday, below you will find my Screen Junkies interview where I chat with Hal Rudnick about some of the science in Interstellar. We covered a lot of topics and went into a lot of detail, but a lot of that is on the cutting room floor in order to make a svelte (but relatively generous) ten minute cut. I hope you enjoy it. (See my earlier thoughts on why I think scientists need […] Click to continue reading this post
After emerging from a spectacular 70mm viewing of Interstellar at the Arclight Dome last night, I was grinning from ear to ear, which is unusual these days after seeing a film in this subject area (science fiction, space travel, the future of humanity, etc). (And by science fiction here I mean proper science fiction, not space opera or space adventure. There’s a lot of that and some of it is fun and makes me grin too, like this Summer’s Guardians of the Galaxy. But that’s not at all the same sort of thing.)
I’m not going to go into any details, since I am very tired of the practice of talking about films to the extent that you say so much of what happens that it is impossible for someone to enjoy watching the film unfold in front of them without knowing what comes next, the way I like my films best. So I’m not going to ruin things for you.
Everybody keeps asking me “what did you think of the science?” since they know that there’s a lot of stuff in there that relates to my subject area and interests. Many seem to want me to pronounce on what’s “good” and whats “bad” about the science, as though I’ve (like many scientists in the public sphere seem to have done) elected myself some sort of guardian of scientific ideas. Let me say two things. The first is that this is a science fiction film, not a science documentary. I’m already hearing all sort of humourless declarations about this and that and the other being wrong and how shameful it is, as happened with Gravity last year. Done right, such discussions can be an opportunity to teach a bit about science ideas, but most often it just comes across as being a smartass, which is a bit tedious, and leads me to my second point.
The second point is something I say a lot and needs to be said a lot more: Scientists don’t own science and its concepts and ideas. We should be careful […] Click to continue reading this post
I’m a fan of Chris Nolan’s work so I’ve been looking forward to Interstellar. I’ve also been fascinated by the McConaussance – the transformation of Matthew McConaughey into an actor of considerable stature in a series of excellent films (Mud, Dallas Buyers Club, etc…), so I’ve been doubly interested in seeing how he works in a film under Nolan’s direction. Same for the always amazing Casey Affleck. All quite exciting to see.
But then to my surprise it turns out there’s another reason to be interested. Kip Thorne. Some years ago, at a party when I last saw him, Kip told me that he had been working on some film or other with a major studio, but I did not know of the details. Then I ran into a mutual friend a couple of months ago who said something a long the lines of “Kip’s movie is coming out soon…”, and I learned that it was something to do with Interstellar! But I did not know any details.
Then I got sent* this Wired story, and then** this story, and I finally got around to looking. The Wired story has a lot of interesting detail, including a special film (that I ought to look at at) with interviews and behind the scenes material (the still to the right is a screen shot from it). The film will apparently feature a black hole and a wormhole in some way (I don’t want to know more – I like films to unfold in front of me in the theatre). Kip has been working with the visual effects people to get right exactly how such objects really look, an issue that has not really been fully addressed, it seems. He, like a number of us interested in science and film, is keen to help filmmakers really do a good job of representing some of these fascinating objects as accurately as possible. (Not, in my view, in order to stifle filmmakers’ imagination, as it so often seems when you hear scientists out there pontificating about what’s wrong in one film or another, but because the actual science is so very often far more interesting and full of delights and possibility than a visual effects kluge can be…) So apparently he wrote down […] Click to continue reading this post
There has been quite a bit of discussion of the realisation that the exciting announcement made by the BICEP2 experiment back in March (see my post here) was based on erroneous analysis. (In brief, various people began to realise that most, if not all, of what they observed could be explained in terms of something more mundane than quantum spacetime fluctuations in the ultra-early universe – the subtle effects of galactic dust. A recent announcement by another experiment, the Planck team, have quantified that a lot.)
While there has been a bit of press coverage of the more sober realisations (see a nice June post on NPR’s blog here), it is (as with previous such cases) nowhere near as high profile as the initial media blitz of March, for better or worse. I think that “worse” might be the case here, since it is important to communicate to the public (in a healthy way) that science is an ongoing process of discovery, verification, and checking and re-checking by various independent teams and individuals. It is a collective effort, with many voices and the decentralised ever-sceptical scientific process itself, however long it takes, ultimately building and broadening the knowledge base. This self-checking by the community, this reliance on independent confirmation of […] Click to continue reading this post
You may recall that back in June I had a chat with Hal Rudnick over at Screen Junkies about science and time travel in various movies (including the recent “X-Men: Days of Future Past”). It was a lot of fun, and people seemed to like it a lot. Well, some good news: On Tuesday we recorded (along with my Biophysicist colleague Moh El-Naggar) another chat for Screen Junkies, this time talking a bit about the fun movie “Guardians of the Galaxy”! Again, a lot of fun was had… I wish you could hear all of the science (and more) that we went into, but rest assured that they* did a great job of capturing some of it in this eight-minute episode. Have a look. (Embed below the more-click):
[…] Click to continue reading this post
So tonight (meaning the wee hours of Monday morning and the next few mornings, for optimum viewing – more civilised hours might work too, of course) the Perseid meteor shower will be on view! Have a look at this site (picked at random; there are many more) for more about how to view the meteors, in case you’re not sure. Well, here’s an interesting thing. The moon will be at its brightest as well, so that’ll mean that the viewing conditions for meteors will not be ideal, unfortunately. And it really will be extra bright (well, slightly, to be honest) because tonight’s full moon is during the moon’s closest approach to […] Click to continue reading this post
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
[Update: Over the months following the announcement, doubt was cast over exactly what BICEP2 saw, and now it seems that the signal announced by BICEP2 is consistent with polarisation produced by galactic dust. See here.]
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