…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
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
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
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
You might not know the name Maurice Murphy, but I am certain that you are likely to know – and maybe even be very familiar with – his work. His is the principal trumpet playing the lead themes in very many films with music by John Williams. I have for a long time been very impressed with how so many of those themes trip so easily off the tongue (physical or mental) and seem to fit together so well (just hum the Star Wars theme, and then follow it by the Superman theme, then the Indiana Jones theme, and so on). A lot of this is due to the fact that Williams (like most good composers) is a master at recycling and modifying, creating a cluster of much loved (deservedly) themes that accompany some of our favourite movie-going memories, but I now think that the other reason is that you’re hearing them all played by the same voice! That voice is the playing of Maurice Murphy, the truly wonderful trumpeter who Williams would specifically request to play the lead on recordings of his film music. Murphy died recently, and you can dig a bit more about him and explore what I’ve been telling you further by going to the London Symphony Orchestra’s site devoted to him […] Click to continue reading this post
You can read a bit about the work of my colleague Elena Pierpaoli and her postdocs and students in this article in one of USC’s in-house publications. It focuses on the Planck observatory (image right from NASA/ESA), which we’ve discussed here before. (Recall the launch?) There’s a lot of exciting physics about the very young universe to be discovered as more data from the mission get gathered and analyzed.
Enjoy the article!
-cvj Click to continue reading this post
Well, here we go. It has been a little over 20 years since I’ve been actively working in this field and have been hearing about the promise of this machine, the Large Hadron Collider (LHC), and now it is really here, working, and colliding protons at an energy much higher than any previous experiment, promising us to a glimpse of new aspects of how the universe works. It is not guaranteed, of course, but there’s a great deal of hope, and so much of what we know strongly suggests that there’s going to be some exciting things to learn. See the list of related posts below for several bits of background on the LHC, or go to CERN’s website. [Image above right -click for larger view- is a CERN-supplied montage of data/images from the various experiments at the LHC. Caption: 7 TeV collision events seen today by the LHC’s four major experiments (clockwise from top-left: ALICE, ATLAS, CMS, LHCb).]
Two of the things foremost in people’s minds are on one hand the Higgs (the particle or particles that ultimately give masses to the elementary particles that make up the […] Click to continue reading this post
Tomorrow is the Big Day. For what? The launch of Planck and Herschel – Major new windows on our universe. Keep your fingers crossed for luck!
They’re on the launch pad right now. See here.
So, what are the missions and objectives of these fine spacecraft, I hear you ask.
Well, from the Planck site: […] Click to continue reading this post
(Categorically Not! presenters and performers on 1st Feb. 2009)
The next Categorically Not! is on Sunday February 1st. The Categorically Not! series of events that are held at the Santa Monica Art Studios, (with occasional exceptions). It’s a series – started and run by science writer K. C. Cole – of fun and informative conversations deliberately ignoring the traditional boundaries between art, science, humanities, and other subjects. I strongly encourage you to come to them if you’re in the area. Here is the website that describes past ones, and upcoming ones. See also the links at the end of the post for some announcements and descriptions (and even video) of previous events.
The theme this month is Dark Matters. Here’s the description from K C Cole:
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Just the other day, while coordinating some work being done on my house, I was thinking that it is time I learned Spanish. Most of the people working in the construction industry here in Los Angeles have Spanish as their first language, and besides the usefulness it would give in communicating difficult ideas about a piece of work to be carried out, I really don’t like the feeling that I’m disconnected from them. I’d like to be able at least to, in Spanish, offer a cup of coffee, or a glass of iced water, and have a little small talk – treat them like fellow human beings as opposed to “the help” as is done so much in this city, to my disgust. I interact a lot with the Spanish-speaking parts of the city through my use of public transport, places I go to grab tasty food from time to time, and so on, but there is still a sense that there is an entire alternative Los Angeles out there that I am only barely touching upon by not knowing the language.
Then yesterday this whole Spanish language issue came up again in a big way. There was a phone call to the department from Univision, the Spanish-language TV network. Probably most of you are wondering what that is. You know those several channels that you never watch and when you flick by them, all clustered together, they’re always speaking Spanish and discussing issues or people that you seldom (if ever) have heard of? Yes. This is one of those channels. There’s a huge part of America (and elsewhere) that tune to those channels primarily.
Well, the people at Univision had heard about the excitement about the Large Hadron Collider (see, e.g. last post) and wanted to do a piece on it, and have someone in the studio to talk about it live on their breakfast show. They were looking for a […] Click to continue reading this post
Well, the new orbiting instrument, GLAST (Gamma-ray Large Area Space Telescope – launched June 11th this year) has passed all its tests with flying colours, apparently, and is working well. NASA has now renamed the craft the Fermi Gamma-ray Space Telescope, after Enrico Fermi. There’s a press release here.
The craft is a wonderful combination of the fields of particle physics, astrophysics and cosmology, and will teach us so much about the universe (such as the nature of dark matter), and so it is exciting to hear that it all on track.
Excitingly, they’ve also released images of the early results of the observations, and you can read more about them in the press release too. Here’s a sky map made from the observations.
This all-sky view from GLAST reveals bright emission in the plane of the Milky Way (center), bright pulsars and super-massive black holes. Credit: NASA/DOE/International LAT Team.
Some words from the release: […] Click to continue reading this post
Good news everyone! GLAST has been launched successfully. GLAST stands for Gamma-ray Large Area Space Telescope, and it does exactly what it says on the packet. It is an instrument designed to look more closely at gamma rays from outer space. More here. It will help (alongside other instruments such as SWIFT) get better understanding of a wide range of gamma-ray emitting objects, that pertain to a wide range of issues, astrophysical to cosmological.
“Gamma ray bursters” are obvious super-powerful sources of gamma rays out there, largely due to macroscopic astrophysical objects (collapsed stars or stars in the process of doing so, or merging with each other – see earlier posts) doing violent things, or interacting violently with their surroundings. So are active galactic nuclei, powered by black holes. We’d like to better understand all of the processes that allow these objects to generate gamma rays.
Other sources could include particles and antiparticles annihilating each other and (by […] Click to continue reading this post
I don’t mean that in a bad way. It is what it is. Quite varied and wonderful, our universe is, with unexpected features I don’t think many would have guessed at not long ago (like the fact that we only understand what about 4% of it is!! Crazy, in a […] Click to continue reading this post
Now have a look at this object (and its enlargement on the right):
What is it? It’s a double Einstein ring! An Einstein ring is formed by gravitational lensing – the bending of light from one object by the gravity of another object – and is typically formed when a distant galaxy lines up with another, closer galaxy. The result is a rather nice ring shape.
To find a double Einstein ring is rare! In fact, this is the first one that’s been announced. Not only is it novel, it can also use used to do a good deal of science, such […] Click to continue reading this post
While searching through their site to find something else, I noticed that there was a conversation on KPCC’s Zocalo between science writer K C Cole and Astrophysicist Chuck Steidel not long ago. Have a look at their listing of past conversations here – there’s a lot of good stuff about various topics and people in the Los Angeles area. I listened to it, and it’s very interesting indeed.
It is not quite your usual light touch conversation that you hear on public radio – it is a little more involved, taking you a bit further (without losing you) and gives you more insights into the work, the puzzles, the discoveries and the hopes for future ones. As a journalist, and the guest host of the program, K C Cole knows her material, and so is able to steer things rather well, while inserting useful remarks to help the listener keep up. This might be perfect listening if you want to get a sense of what it’s like to work in Chuck’s area of expertise (finding and characterizing the youngest galaxies and understanding their cosmological implications), either out of general curiosity or if you’re planning a career in that area. Take out some time and have a listen. Here’s the blurb from the site:
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(Click for larger view.)
This lovely composite image of Abell 520 that includes an inferred distribution of dark […] Click to continue reading this post
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 […] Click to continue reading this post
Have a look at this:
What is it? It is an image of part of the three dimensional (see below) distribution of clumps of dark matter in our universe, produced by an extensive survey using the Hubble telescope. How did they produce it, given that dark matter is -by definition- not visible? They deduced the presence of the chunks of dark matter by looking at the gravitational […] Click to continue reading this post
Well, youâ€™re sitting there at the desk, so might as well put on the radio to keep yourself company. Do in on the web, and I suggest that you listen to:
Radio Lab episode #205
This one was about Space. It has a lot of good stuff in it, and excellent speakers, very good clips, and playful (rather successfully, surprisingly often) presenters. My favourite bit? Neil DeGrasse Tyson being interviewed about our place in the universe. If youâ€™re not an expert on the anatomy of the idea, please have a listen, since this is one of the best (and quite funny) laypersonâ€™s quick descriptions Iâ€™ve heard on the subject.
Tim Ferris (on the unlikelihood or likelihood of travelling vast distances for expeditions in space) and Brian Greene (on the geometry of our universe – another good layperson’s level chat) are also in this segment, just before. Direct mp3 file link to that particular piece here.
-cvj Click to continue reading this post
I learned from New Scientist just now that various researchers working on modified gravity theories are casting doubt on the direct evidence of Dark Matter that was presented by Douglas Clowe and collaborators a few weeks ago. Recall an earlier post on it, here, and Sean Carroll’s post with more … Click to continue reading this post
I learned from an article in New Scientist by David Shiga that there have been recently found four more small satellite galaxies of our Milky Way galaxy. The satellites are dwarf galaxies a few hundred to a few thousand light years across. The tiny galaxies are thought to be the … Click to continue reading this post
I learned a new term from a producer at a television studio the other day (in a context I do not know if I’m allowed to blog about yet): “Spinach TV”. I love it. This is a term expressing the idea of television programming that is supposed to be “good … Click to continue reading this post
Well, the press conference I told you about has happened! This is so exciting! There’s new and very direct proof from observations of the Bullet Cluster with the Chandra X-ray Observatory that Dark Matter really exists. So the need to make modifications to how gravity works on large scales in … Click to continue reading this post