Results tagged “CMB”

Les autres choses (scientifique)

I’ve been meaning to give a shout-out to my colleagues on the ADAMIS team at the APC (AstroParticule et Cosmologie) Lab at the Université Paris 7 for a while: in addition to doing lots of great work on Planck, EBEX, PolarBear and other important CMB and cosmology experiments, they’ve also been running a group blog since the Autumn, Paper(s) of the Week et les autres choses (scientifique) which dissects some of the more interesting work to come out of the cosmology community. In particular, one of my favorite collaborators has written an extremely astute analysis of what, exactly, we on the Planck team released in our lengthy series of papers last month (which I have already discussed in a somewhat more boosterish fashion).

Planck: First results

The Satellite now known as the Planck Surveyor was first conceived in the mid-1990s, in the wake of the results from NASA’s COBE Satellite, the first to detect primordial anisotropies in the Cosmic Microwave Background (CMB), light from about 400,000 years after the big bang. (I am a relative latecomer to the project, having only joined in about 2000.)

After all this time, we on the team are very excited to produce our very first scientific results. These take the form of a catalog of sources detected by Planck, along with 25 papers discussing the catalog as well as the more diffuse pattern of radiation on the sky.

Planck is the very first instrument to observe the whole sky with light in nine bands with wavelengths from about 1/3 of a millimeter up to one centimeter, an unprecedented range. In fact this first release of data and papers discusses Planck as a tool for astrophysics — as a telescope observing distant galaxies and clusters of galaxies as well as our own Galaxy, the Milky Way. All of these glow in Planck’s bands (indeed they dominate over the CMB in most of them), and with our high-sensitivity all-sky maps we have the opportunity to do astronomy with Planck, the best microwave telescope ever made. Indeed, to get to this point, we actually have to separate out the CMB from the other sources of emission and, somewhat perversely, actively remove that from the data we are presenting.

Over the last year, then, we on the Planck team have written about 25 papers to support this science; a few of them are about the mission as a whole, the instruments on board Planck, and the data processing pipelines that we have written to produce our data. Then there are a few papers discussing the data we are making available, the Early Release Compact Source Catalog and the various subsets discussing separately objects within our own Milky Way Galaxy as well as more distant galaxies and clusters of galaxies. The remaining papers give our first attempts at analyzing the data and extracting the best science possible.

Most of the highlights in the current papers provide confirmation of things that astronomers have suspected, thanks to Planck’s high sensitivity and wide coverage. It has long been surmised that most stars in the Universe are formed in locations shrouded by dust, and hence not visible to optical telescopes. Rather, the birth of stars heats the dust to temperatures much lower than that of stars, but much higher than the cold dust far from star-forming regions. This warm dust radiates in Planck’s bands, seen at lower and lower frequencies for more and more distant galaxies (due to the redshift of light from these faraway objects). For the first time, Planck has observed this Cosmic Infrared Background (CIB) at frequencies that may correspond to galaxies forming when the Universe was less than 15% of its current age, less than 2 billion years after the big bang. Here is a picture of the CIB at various places around the sky, specifically chosen to be as free as possible of other sources of emission:
Cosmic Infrared Background

Another exciting result has to do with the properties of that dust in our own Milky Way Galaxies. This so-called cosmic dust is known to be made of very tiny grains, from small agglomerations of a few molecules up to those a few tens of micrometers across. Ever since the mid-1990s, there has been some evidence that this dust emits radiation at millimeter wavelengths that the simplest models could not account for. One idea, actually first proposed in the 1950s, is that some of the dust grains are oblong, and receive enough of a kick from their environment that they spin at very high rates, emitting radiation at a frequency related to that rotation. Planck’s observations seem to confirm this prediction quantitatively, seeing its effects in our galaxy. This image of the Rho Ophiuchus molecular cloud shows that the spinning dust emission at 30 GHz traces the same structures as the thermal emission at 857 GHz:
Spinning Dust

In addition, Planck has found more than twenty new clusters of galaxies, has mapped the dust in gas in the Milky Way in three dimensions, and uncovered cold gas in nearby galaxies. And this is just the beginning of what Planck is capable of. We have not yet begun to discuss the cosmological implications, nor Planck’s abilities to measure not just the intensity of light, but also its polarization.

Of course the most important thing we have learned so far is how hard it is to work in a team of 400 or so scientists, whom — myself included — like neither managing nor being managed (and are likewise not particularly skilled at either). I’ve been involved in a small way in the editing process, shepherding just a few of those 25 papers to completion, paying attention to the language and presentation as much as the science. Given the difficulties, I am relatively happy with the results — the papers can be downloaded directly from ESA, and will be available on the ArXiV on 12 January 2011, and will eventually be published in the journal Astronomy and Astrophysics. It will be very interesting to see how we manage this in two years when we may have as many as a hundred or so papers at once. Stay tuned.

Consider a Spherical Cow (Company)

One of my old friends from graduate school, and a colleague to the present day, Lloyd Knox — whom you may remember from such cosmology hits as the Dark Energy Song — has started an initiative to create “short documentary videos to demonstrate the explanatory power of simple physical models and to help us understand and aesthetically appreciate the natural world”. It’s called The Spherical Cow company — the name comes from the traditional physicists’ trick of idealizing and simplifying any problem he or she gets, sometimes out of all recognition — but usually, when done well, keeping enough of the salient features.

The first video does just that, giving a simple description of the formation of the Cosmic Microwave Background, in the form of a conversation between Lloyd and his son, Teddy — with interpolations for animations and narration. Even with those occasional animations, the whole thing is pleasingly low-fi, but well-explained and charming (especially so for me, as I know the protagonists). I look forward to the next videos in the series, and I’ll certainly be recommending them to students of all ages.


I spent part of this week in Paris (apparently at the same time as a large number of other London-based scientists who were here for other things) discussing whether the European CMB community should rally and respond to ESA’s latest call for proposals for a mission to be launched in the next open slot—which isn’t until around 2022.

As successful as Planck seems to be, and as fun as it is working with the data, I suspect that no one on the Planck team thinks that a 400-scientist, dispersed, international team coming from a dozen countries each with its own politics and funding priorities, is the most efficient way to run such a project. But we’re stuck with it—no single European country can afford the better part of a billion Euros it will cost. Particle physics has been in this mode for the better part of fifty years, and arguably since the Manhattan Project, but it’s a new way of doing things — involving new career structures, new ways of evaluating research, new ways of planning, and a new concentration upon management — that we astrophysicists have to develop to answer our particular kinds of scientific questions.

But a longer discussion of “big science” is for another time. The next CMB satellite will probably be big, but the coming ESA call is officially for an “M-class” (for “medium”) mission, with a meagre (sic) 600 million euro cap. What will the astrophysical and cosmological community get for all this cash? How will it improve upon Planck?

Well, Planck has been designed to mine the cosmic microwave background for all of the temperature information available, the brightness of the microwave sky in all directions, down to around a few arcminutes at which scale it becomes smooth. But light from the CMB also carries information about the polarisation of light, essentially two more numbers we can measure at every point. Planck will measure some of this polarisation data, but we know that there will be much more to learn. We expect that this as-yet unmeasured polarisation can answer questions about fundamental physics that affects the early universe and describes its content and evolution. What are the details of the early period of inflation that gave the observable Universe its large-scale properties and seeded the formation of structures in it—and did it happen at all? What are the properties of the ubiquitous and light neutrino particles whose presence would have had a small but crucial effect on the evolution of structure?

The importance of these questions is driving us toward a fairly ambitious proposal for the next CMB mission. It will have a resolution comparable to that of Planck, but with many hundreds of individual detectors, compared to Plank’s many dozens—giving us over an order of magnitude increase in sensitivity to polarisation on the sky. Actually, even getting to this point took a good day or two of discussion. Should we instead make a cheaper, more focused proposal that would concentrate only on the question oaf inflation and in particular upon the background of gravitational radiation — observable as so-called “B-modes” in polarisation — that some theories predict? The problem with this proposal is that it is possible, or even likely, that it will produce what is known as a “null result”—that is, it won’t see anything at all. Moreover, a current generation of ground- and balloon-based CMB experiments, including EBEX and Polarbear, which I am lucky enough to be part of, are in progress, and should have results within the next few years, possibly scooping any too-narrowly designed future satellite.

So we will be broadening our case beyond these B-modes, and therefore making our design more ambitious, in order to make these further fundamental measurements. And, like Planck, we will be opening a new window on the sky for astrophysicists of all stripes, giving measurements of magnetic fields, the shapes of dust grains, and likely many more things we haven’t yet though of.

One minor upshot of all this is that our original name, the rather dull “B-Pol”, is no longer appropriate. Any ideas?

The Planck Sky Previewed

The Planck Satellite was launched in May 2009, and started regular operations late last summer. This spring, we achieved an important milestone: the satellite has observed the whole sky.

To celebrate, the Planck team have released an image of the full sky. The telescope has detectors which can see the sky with 9 bands at wavelengths ranging from 0.3 millimeters up to nearly a centimeter, out of which we have made this false-color image. The center of the picture is toward the center of the Galaxy, with the rest of the sphere unwrapped into an ellipse so that we can put it onto a computer screen (so the left and right edges are really both the same points).

The microwave sky

At the longest and shortest wavelengths, our view is dominated by matter in our own Milky Way galaxy — this is the purple-blue cloud, mostly so-called galactic “cirrus” gas and dust, largely  concentrated in a thin band running through the center which is the disk of our galaxy viewed from within.

In addition to this so-called diffuse emission, we can also see individual, bright blue-white objects. Some of these are within our galaxy, but many are themselves whole distant galaxies viewed from many thousands or millions of light years distance. Here’s a version of the picture with some objects highlighted:


Even though Planck is largely a cosmology mission, we expect these galactic and extragalactic data to be invaluable to astrophysicists of all stripes. Buried in these pictures we hope to find information on the structure and formation of galaxies, on the evolution of very faint magnetic fields, and on the evolution of the most massive objects in the Universe, clusters of galaxies.

But there is plenty of cosmology to be done: we see the Cosmic Microwave Background (CMB) in the red and yellow splotches at the top and bottom — out of the galactic plane. We on the Planck team will be spending much of the next two years separating the galactic and extragalactic “foreground” emission from the CMB, and characterizing its properties in as much detail as we can. Stay tuned.

I admit that I was somewhat taken aback by the level of interest in these pictures: we haven’t released any data to the community, or written any papers. Indeed, we’ve really said nothing at all about science. Yet we’ve made it onto the front page of the Independent and even the Financial Times, and yours truly was quoted on the BBC’s website. I hope this is just a precursor to the excitement we’ll generate when we can actually talk about science, first early next year when we release a catalog of sources on the sky for the community to observe with other telescopes, and then in a couple of years time when we will finally drop the real CMB cosmology results.

Andrew Lange, Huan Tran

The cosmology community has had a terrible few months.

I am saddened to report the passing of Andrew Lange, a physicist from CalTech and one of the world’s preeminent experimental cosmologists. Among many other accomplishments, Andrew was one of the leaders of the Boomerang experiment, which made the first large-scale map of the Cosmic Microwave Background radiation with a resolution of less than one degree, sufficient to see the opposing action of gravity and pressure in the gas of the early Universe, and to use that to measure the overall density of matter, among many other cosmological properties. He has since been an important leader in a number of other experiments, notably the Planck Surveyor satellite and the Spider balloon-borne telescope, currently being developed to become one of the most sensitive CMB experiments ever built.

I learned about this tragedy on the same day that people are gathering in Berkeley, California, to mourn the passing of another experimental cosmologist, Huan Tran of Berkeley. Huan was an excellent young scientist, most recently deeply involved in the development of PolarBear, another one of the current generation of ultra-sensitive CMB experiments. Huan lead the development of the PolarBear telescope itself, currently being tested in the mountains of California, but to be deployed for real science on the Atacama plane in Chile. We on the PolarBear team are proud to name the PolarBear telescope after Huan Tran, a token of our esteem for him, and a small tribute to his memory.

My thoughts go out to the friends and family of both Huan and Andrew. I, and many others, will miss them both.

Planck's First Light

I’m happy to be able to point to ESA’s first post-launch press release from the Planck Surveyor Satellite.

Here is a picture of the area of sky that Planck has observed during its “First Light Survey”, superposed on an optical image of the Milky Way galaxy:


(Image credit: ESA, LFI and HFI Consortia (Planck); Background image: Axel Mellinger. More pictures are available on the UK Planck Site as well as in French.)

The last few months since the launch have been a lot of fun, getting to play with Planck data ourselves. Here at Imperial, our data-processing remit is fairly narrow: we compute and check how well the satellite is pointing where it is supposed to, and calculate the shape of its beam on the sky (i.e., how blurry its vision is). Nonetheless, just being able to work at all with this incredibly high-quality data is satisfying.

Because of the way Planck scans the sky, in individual rings slowly stepping around the sky over the course of about seven months, with a nominal mission of two full observations of the sky, even the two weeks of “First Light Survey” data is remarkably powerful: we have seen a bit more than 5% of the sky with about half of the sensitivity that Planck is meant to eventually have (in fact, we hope to extend the mission beyond the initial 14 months). This is already comparable to the most powerful sub-orbital (i.e., ground and balloon-based) CMB experiments to date.

But a full scientific analysis will have to wait a while: after the 14 month nominal mission, we will have one year to analyze the data, and another year to get science out of it before we need to release the data alongside, we hope, a whole raft of papers. So stay tuned until roughly Autumn of 2012 for the next big Planck splash.

I was sitting in the lecture theatre of the Royal Institution at the Science Online London meeting (of which I hope to write more later, but you can retroactively follow the day’s tweets or just search for the day’s tags) when I realized I had missed the fifth anniversary of this blog this past July. So: thanks for your attention for over 400 posts on cosmology, astrophysics, Bayesian probability and probably too much politics and religion.

Today is also a much more important date: the 400th anniversary of Galileo’s telescope. Even Google is celebrating.

Right now, I’m at a meeting in Cambridge discussing Primordial Gravitational Waves — ripples in space and time that have been propagating since the first instants after the big bang. Despite my training as a theoretical physicist, I’m here to discuss the current state of the art of experiments measuring those waves using the polarization of the cosmic microwave background, which probes the effect of those gravitational waves on the constituents of the Universe about 400,000 years after the big bang. Better go finish writing my talk.

[Warning: this post will be fairly technical and political and may only be of interest to those in the field.]

I spent the first couple of days this week stuck in a room in Cambridge with about 40 of my colleagues pondering a very important question: what is the future of the study of the Cosmic Microwave Background in the UK?

Organized by Keith Grainge of Cambridge’s MRAO, and held at Cambridge’s new Kavli Institute for Cosmology, the workshop brought together a significant fraction of the UK CMB community, from Cambridge itself, Cardiff, Imperial, Manchester, Oxford and elsewhere.

With the recent cancellation of the Clover experiment by STFC, there is no major UK-led CMB experiment (I am making a distinction between CMB experiments per se and those with other primary purposes, such observing the Sunyaev-Zel’dovich effect with AMI, or astrophysical foregrounds with QUIJOTE.) However, there is a huge amount of CMB expertise in the UK, from the design of detectors and telescopes through to the analysis of CMB data.

In the short term, it seems there is some appetite for attempting to revive the Clover effort at some level, perhaps in collaboration with other experimental teams outside of the UK. The major driver — and the only way it makes any sense at all — is to get this done quickly, before the other experiments pursuing the same goals begin to gather data (in the interests of full disclosure, I should point out that I am involved in a couple of those other experiments: EBEX and PolarBear). This decision, I imagine, will be dominated by the politics and economics of the current STFC funding debacle fiasco debate as well as what I understand are the internal relationships of the Clover team.

So of more scientific interest is the question of what to do next. Right now, the UK astronomy and particle physics community is undertaking a series of consultations to figure out what it thinks are the most important topics, instruments and experiments to concentrate upon over the next few years. One very real possibility is that we could decide not to lead any new CMB experiments, but just to continue to lend our expertise to other efforts. This is cost-effective but unsatisfying, especially to experimentalists who want to take the lead in the design of new efforts. The only viable alternative, I think, is for the community to come together and, with apologies for the cliche, speak with a unified voice in support of a coherent plan. There is enough expertise in the UK to produce great CMB science over the next decade, but it is thinly spread. The basic design of any such experiment is clear: thousands of detectors observing the sky over as many frequencies as possible. But the details — exactly what sorts of detectors, flown from a balloon or stationary on the ground, or to wait for a future satellite — will be crucial to the success or otherwise of the experiment. Unfortunately, these decisions can often degenerate into “not-invented-here” syndrome and personality clashes between strong scientific egos. But as Ben Franklin said on signing the Declaration of Independence, “we must, indeed, all hang together, or assuredly we shall all hang separately.”

Another launch

Not all CMB (Cosmic Microwave Background) experiments get launched on a rocket.

There’s a long history of telescopes flown from balloons — huge mylar balloons floating over 100,000 feet in the air. MAXIMA and BOOMERaNG, the first experiments to map out the microwave sky on the sub-degree scales containing information about the detailed physical conditions in the Universe over the first few hundred thousand years after the Big Bang. The Planck Satellite will close out that era of CMB experiments, by giving us a complete picture of the microwave sky down to less than a tenth of a degree.

But there is still more to be done, even beyond what Planck is capable of. By measuring the polarization of the microwave background at even higher sensitivities than Planck, we hope to observe the effects of gravitational radiation in the early Universe.

Last week, EBEX, one of a new generation of balloon-borne experiments designed specifically with this goal, had its maiden flight from Fort Sumner, New Mexico.

EBEX Launch, 6/11/09 from asad137 on Vimeo.

It’s worth remembering, of course, that even with a parachute, these telescopes hit the ground pretty hard. But these things are amazingly well-built, and the EBEX crew have managed to recover most of the hardware and all of the data. So now the team have some time to get the hardware and software ready to fly for a couple of weeks over Antarctica next year.

And let’s not forget that New Mexico is also the home of Roswell, where conspiracy theorists and other wackjobs have been trying to find the government cover-up of UFO sightings. Indeed, the EBEX balloon was spotted, but at least in neighbouring Arizona, they can tell the difference.

Meanwhile, another CMB experiment, PolarBear, is about to start its first set of important tests. PolarBear is a ground-based telescope, which means it can watch the sky for far longer than a balloon, at the cost of being at the bottom of the atmosphere and all of the extra noise that adds to the signal. So despite some hard times (especially here in the UK), the next generation of CMB experiments are on the way, hoping to probe all the way back to the epoch of inflation.

Loading Planck

The Planck Surveyor Satellite has finished its assembly and testing in Liège, Belgium, and this week was loaded onto a Volga-Dnepr Antonov AN-124 plane, and sent to Kourou, French Guiana, location of the Centre Spatial Guyanais (one of the few places near the Equator politically connected to Europe). It’s due to be launched in tandem with Herschel on April 16. Here are some pictures of the “Planck Transport and Storage Container” making its way on a “Convoi Exceptionnel” to the airstrip. These photos came to me third-hand, so my apologies and thanks to the unknown (to me) photographer.
342-Planck entering container in CSL 344-Truck in position 347-Planck loaded on truck 352-Transfer on ramp 354-Planck inside the plane

Bayesian Inference in the NY Times

In today’s Sunday NY Times Magazine, there’s a long article by psychologist Steven Pinker, on “Personal Genomics”, the growing ability for individuals to get information about their genetic inheritance. He discusses the evolution of psychological traits versus intelligence, and highlights the complicated interaction amongst genes, and between genes and society.

But what caught my eye was this paragraph:

What should I make of the nonsensical news that I… have a “twofold risk of baldness”? … 40 percent of men with the C version of the rs2180439 SNP are bald, compared with 80 percent of men with the T version, and I have the T. But something strange happens when you take a number representing the proportion of people in a sample and apply it to a single individual…. Anyone who knows me can confirm that I’m not 80 percent bald, or even 80 percent likely to be bald; I’m 100 percent likely not to be bald. The most charitable interpretation of the number when applied to me is, “If you knew nothing else about me, your subjective confidence that I am bald, on a scale of 0 to 10, should be 8.” But that is a statement about your mental state, not my physical one. If you learned more clues about me (like seeing photographs of my father and grandfathers), that number would change, while not a hair on my head would be different. [Emphasis mine].

That “charitable interpretation” of the 80% likelihood to be bald is exactly Bayesian statistics (which I’ve talked about, possibly ad nauseum, before) : it’s the translation from some objective data about the world — the frequency of baldness in carriers of this gene — into a subjective statement about the top of Pinker’s head, in the absence of any other information. And that’s the point of probability: given enough of that objective data, scientists will come to agreement. But even in the state of uncertainty that most scientists find themselves, Bayesian probability forces us to enumerate the assumptions (usually called “prior probabilities”) that enter into our assignments reasoning along with the data. Hence, if you knew Pinker, your prior probability is that he’s fully hirsute (perhaps not 100% if you allow for the possibility of hair extensions and toupees); but if you didn’t then you’d probably be willing to take 4:1 odds on a bet about his baldness — and you would lose to someone with more information.

In science, of course, it usually isn’t about wagering, but just about coming to agreement about the state of the world: do the predictions of a theory fit the data, given the inevitable noise in our measurements, and the difficulty of working out the predictions of interesting theoretical ideas? In cosmology, this is particularly difficult: we can’t go out and do the equivalent of surveying a cross section of the population for their genes: we’ve got only one universe, and can only observe a small patch of it. So probabilities become even more subjective and difficult to tie uniquely to the data. Hence the information available to us on the very largest observable scales is scarce, and unlikely to improve much, despite tantalizing hints of data discrepant with our theories, such as the possibly mysterious alignment of patterns in the Cosmic Microwave Background on very large angles of the sky (discussed recently by Peter Coles here). Indeed, much of the data pointing to a possible problem was actually available from the COBE Satellite; results from the more recent and much more sensitive WMAP Satellite have only reinforced the original problems — we hope that the Planck Surveyor — to be launched in April! — will actually be able to shed light on the problem by providing genuinely new information about the polarization of the CMB on large scales to complement the temperature maps from COBE and WMAP.


A quick pointer to Initiative for Cosmology (iCosmo). The website brings together a bunch of useful calculations for physical cosmology — relatively simple quantities like the relationship between redshift and distance, and also more complicated ones like the power spectrum of density perturbations (which tells us the distribution of galaxies on the largest scales in the Universe) and quantities derived from that like the distortions in the shapes of galaxies due to gravitational lensing, when the path of light from galaxies is perturbed by intervening mass in the Universe. Combined with good documentation and tutorials (and downloadable source), it makes a good companion to sites such as LAMBDA’s CMB toolbox, which provides similar services targeted specifically at Cosmic Microwave Background science. iCosmo looks like it will be useful for researchers in the field as well as students, so thanks and congratulations to its creators (I’d like to point directly at the page listing them, but that doesn’t seem to be possible… instead, there’s a discussion forum at CosmoCoffee.).

OK, not a vacation in the true sense of the word: I’ve been in the US, attending meetings (in Berkeley), workshops (in Santa Fe), conferences (in Pasadena) and, because I can’t seem to escape them, teleconferences everywhere and all the time.


In Berkeley, I attended the first all-hands collaboration meeting for PolarBear, an experiment that will measure the polarization of the CMB from a telescope that will eventually be situated on the Atacama desert plain in Chile — one of the highest, driest, least accessible places on the earth, and one of the least contaminated with light or radio interference. (Despite the name of the experiment, there are no polar bears there.) First, we’ll test it at the somewhat less remote White Mountain facility in California, shake out all the bugs. PolarBear is one of a new generation of experiments that will measure the CMB using not just a few tens of detectors, but a few thousand, which brings with it all sorts of technical challenges. In hardware, the first challenge is simply making so many detectors and keeping their properties uniform each to each — these are among the most sensitive microwave detectors ever built, essentially as good as the constraints of quantum mechanics and thermodynamics allow. The second, related to the first, is to pack as many of these into a small space — the focal plane of the telescope — as possible. Traditionally, microwave detectors have used horns to guide the electromagnetic waves from the sky onto the detectors, but those horns are much wider than the detector hardware. For experiments like PolarBear, we put the detectors themselves right at the focus of the telescope and make each of them into a little antenna, receiving directly the focused light after passing through a hemispherical lens. The final hardware challenge is to get the information from these thousands of detectors off of the telescope and into our computers, which the PolarBear designers have solved with a new technique called “frequency-domain multiplexing”. Sort of like the way FM radio manages to convey the full spectrum of sound by modulating at a particular frequency, the very high-tech SQUIDs (Superconducting QUantum Interference Devices) can then amplify these tiny CMB signals into data we can analyze.

In fact, the data analysis and computing challenges are almost as significant as those faced in hardware. With thousands of detectors and a telescope that will run for the better part of several, we have many orders of magnitude more CMB data than we’ve ever dealt with before, combined with a sensitivity goal better than a millionth of a degree. By adding more and more detectors, we can make the raw experiment itself sensitive enough to do this. What we don’t know is whether we can eliminate everything else that can possibly contaminate our results: light may spill over our shield from the 300 degree ground or directly from the atmosphere; dust in our solar system or our galaxy also glows in the bands we want to measure, as do external galaxies millions of light-years away. So our task is to compress the terabytes of data into a few interesting numbers (like the energy scale of inflation) and to simultaneously separate the cosmic signal from the that produced by instrument and from the rest of the Universe (which may be much brighter!). Suffice to say, we have some good ideas but until we’re confronted with real data we won’t know how successful we’ll be.

Plus, I ate bagels (better than London; not as good as New York) and burritos, and bought shoes at cheap American prices (at least when I think in British Pounds).

Next up, Santa Fe

Gruber Cosmology Prize 2008: Dick Bond

Dick Bond, a friend, mentor and longtime collaborator has won the 2008 Gruber Cosmology prize. Dick’s work has been instrumental at bringing us into this age of “precision cosmology”. He has always concentrated on that interface between theory and observation, making predictions for what we would see in the Cosmic Microwave Background, and how we might best extract that information. The present industry in Cosmological Data Analysis is in no small part down to his ongoing work in the field. To quote the Gruber citation itself:

Professor Bond’s work has provided the theoretical framework to interpret the observed inhomogeneities in the fossil radiation left over from the early stages of expansion of the Universe—the Big Bang. Professor Bond’s research has helped us understand the transition from the nearly featureless early Universe to the wonderfully structured world of galaxies, stars and planets today.

Congratulations, Dick!