Guest Post by Alessandra Buonanno: Nobel Laureates Call for Release of Iranian Student Omid Kokabee

buonannoUsually I start guest posts by remarking on what a pleasure it is to host an article on the topic being discussed. Unfortunately this is a sadder occasion: protesting the unfair detention of Omid Kokabee, a physics graduate student at the University of Texas, who is being imprisoned by the government of Iran. Alessandra Buonanno, who wrote the post, is a distinguished gravitational theorist at the Max Planck Institute for Gravitational Physics and the University of Maryland, as well as a member of the Committee on International Freedom of Scientists of the American Physical Society. This case should be important to everyone, but it’s especially important for physicists to work to protect the rights of students who travel from abroad to study our subject.


Omid Kokabee was arrested at the airport of Teheran in January 2011, just before taking a flight back to the University of Texas at Austin, after spending the winter break with his family. He was accused of communicating with a hostile government and after a trial, in which he was denied contact with a lawyer, he was sentenced to 10 years in Teheran’s Evin prison.

According to a letter written by Omid Kokabee, he was asked to work on classified research, and his arrest and detention was a consequence of his refusal. Since his detention, Kokabee has continued to assert his innocence, claiming that several human rights violations affected his interrogation and trial.

Since 2011, we, the Committee on International Freedom of Scientists (CIFS) of the American Physical Society, have protested the imprisonment of Omid Kokabee. Although this case has received continuous support from several scientific and international human rights organizations, the government of Iran has refused to release Kokabee.

Omid Kokabee

Omid Kokabee has received two prestigious awards:

  • The American Physical Society awarded him Andrei Sakharov Prize “For his courage in refusing to use his physics knowledge to work on projects that he deemed harmful to humanity, in the face of extreme physical and psychological pressure.”
  • The American Association for the Advancement of Science awarded Kokabee the Scientific Freedom and Responsibility Prize.

Amnesty International (AI) considers Kokabee a prisoner of conscience and has requested his immediate release.

Recently, the Committee of Concerned Scientists (CCS), AI and CIFS, have prepared a letter addressed to the Iranian Supreme Leader Ali Khamenei asking that Omid Kokabee be released immediately. The letter was signed by 31 Nobel-prize laureates. (An additional 13 Nobel Laureates have signed this letter since the Nature blog post. See also this update from APS.)

Unfortunately, earlier last month, Kokabee’s health conditions have deteriorated and he has been denied proper medical care. In response, the President of APS, Malcolm Beasley, has written a letter to the Iranian President Rouhani calling for a medical furlough for Omid Kokabee so that he can receive proper medical treatment. AI has also made further steps and has requested urgent medical care for Kokabee.

Very recently, the Iran’s supreme court has nullified the original conviction of Omid Kokabee and has agreed to reconsider the case. Although this is positive news, it is not clear when the new trial will start. Considering Kokabee’s health conditions, it is very important that he is granted a medical furlough as soon as possible.

More public engagement and awareness is needed to solve this unacceptable case of violation of human rights and freedom of scientific research. You can help by tweeting/blogging about it and responding to this Urgent Action that AI has issued. Please note that the date on the Urgent Action is there to create an avalanche effect; it is not a deadline nor it is the end of action.

Alessandra Buonanno for the American Physical Society’s Committee on International Freedom of Scientists (CIFS).

Posted in Guest Post, Human Rights, Science and Society | 13 Comments

Unsolicited Advice: Becoming a Science Communicator

Everyone who does science inevitably has “communicating” as part of their job description, even if they’re only communicating with their students and professional colleagues. But many people start down a trajectory of becoming a research scientist, only to discover that it’s the communicating that they are most passionate about. And some of those people might want to take the dramatic step of earning a living doing such communication, whether it’s traditional journalism or something more new-media focused.

So: how does one make the transition from researcher to professional science communicator? Heck if I know. I do a lot of communicating, but it’s not my primary job. You’d be better off looking at this thread from Ed Yong, where he coaxed an impressive number of science writers into telling their origin stories. But lack of expertise has never stopped me from offering advice!

First piece of advice: don’t make the tragic mistake of looking at science communication as a comfortable safety net if academia doesn’t work out. Not only is it an extremely demanding career, but it’s one that is at least as hard as research in terms of actually finding reliable employment — and the career trajectories are far more chancy and unpredictable. There is no tenure for science communicators, and there’s not even a structured path of the form student → postdoc → faculty. Academia’s “up or out” system can be soul-crushing, but so can the “not today, but who knows? Maybe tomorrow!” path to success of the professional writer. It’s great to aspire to being Neil deGrasse Tyson or Mary Roach, but most science communicators don’t reach that level of success, just as most scientists don’t become Marie Curie or Albert Einstein.

Having said all that, here are some tips that might be worth sharing. Continue reading

Posted in Advice, Science and the Media, Words | 30 Comments

Discovering Tesseracts

I still haven’t seen Interstellar yet, but here’s a great interview with Kip Thorne about the movie-making process and what he thinks of the final product. (For a very different view, see Phil Plait [update: now partly recanted].)

tesseract One of the things Kip talks about is that the film refers to the concept of a tesseract, which he thought was fun. A tesseract is a four-dimensional version of a cube; you can’t draw it faithfully in two dimensions, but with a little imagination you can get the idea from the picture on the right. Kip mentions that he first heard of the concept of a tesseract in George Gamow’s classic book One, Two, Three… Infinity. Which made me feel momentarily proud, because I remember reading about it there, too — and only later did I find out that many (presumably less sophisticated) people heard of it in Madeleine L’Engle’s equally classic book, A Wrinkle in Time.

But then I caught myself, because (1) it’s stupid to think that reading about something for the first time in a science book rather than a science fantasy is anything to be proud of, and (2) in reality I suspect I first heard about it in Robert Heinlein’s (classic!) short story, “–And He Built a Crooked House.” Which is just as fantastical as L’Engle’s book.

So — where did you first hear the word “tesseract”? A great excuse for a poll! Feel free to elaborate in the comments.

Tesseract Poll
Where did you first discover the word "tesseract"?
Posted in Math, Time, Words | 34 Comments

Purposeful Distortion

Here is a map, slightly off-kilter but completely recognizable, by Gaicomo Faiella. Can you tell what is special/interesting about it? (Hat tip to Joe Polchinski, and following his lead I won’t reveal the answer in this post — but feel free to leave guesses/spoilers in the comments.)

map-z

Posted in Arts, World | 29 Comments

The Science of Interstellar

The intersection — maybe the union! — of science and sci-fi geekdom is overcome with excitement about the upcoming movie Interstellar, which opens November 7. It’s a collaboration between director Christopher Nolan and physicist Kip Thorne, both heroes within their respective communities. I haven’t seen it yet myself, nor do I know any secret scoop, but there’s good reason to believe that this film will have some of the most realistic physics of any recent blockbuster we’ve seen. If it’s a success, perhaps other filmmakers will take the hint?

Kip, who is my colleague at Caltech (and a former guest-blogger), got into the science-fiction game quite a while back. He helped Carl Sagan with some science advice for his book Contact, later turned into a movie starring Jodie Foster. In particular, Sagan wanted to have some way for his characters to traverse great distances at speeds faster than light, by taking a shortcut through spacetime. Kip recognized that a wormhole was what was called for, but also realized that any form of faster-than-light travel had the possibility of leading to travel backwards in time. Thus was the entire field of wormhole time travel born.

As good as the movie version of Contact was, it still strayed from Sagan’s original vision, as his own complaints show. (“Ellie disgracefully waffles in the face of lightweight theological objections to rationalism…”) Making a big-budget Hollywood film is necessarily a highly collaborative endeavor, and generally turns into a long series of forced compromises. Kip has long been friends with Lynda Obst, an executive producer on Contact, and for years they batted around ideas for a movie that would really get the science right.

Long story short, Lynda and Kip teamed with screenwriter Jonathan Nolan (brother of Christopher), who wrote a draft of a screenplay, and Christopher eventually agreed to direct. I know that Kip has been very closely involved with the script as the film has developed, and he’s done his darnedest to make sure the science is right, or at least plausible. (We don’t actually whether wormholes are allowed by the laws of physics, but we don’t know that they’re not allowed.) But it’s a long journey, and making the best movie possible is the primary goal. Meanwhile, Adam Rogers at Wired has an in-depth look at the science behind the movie, including the (unsurprising, in retrospect) discovery that the super-accurate visualization software available to the Hollywood special-effects team enable the physicists to see things they hadn’t anticipated. Kip predicts that at least a couple of technical papers will come out of their work.

And that’s not all! Kip has a book coming out on the science behind the movie, which I’m sure will be fantastic. And there is also a documentary on “The Science of Interstellar” that will be shown on TV, in which I play a tiny part. Here is the broadcast schedule for that, as I understand it:

SCIENCE
Wednesday, October 29, at 10pm PDT/9c

AHC (American Heroes Channel)
Sunday, November, 2 at 4pm PST/3c (with a repeat on Monday, November 3 at 4am PST/3c)

DISCOVERY
Thursday, November 6, at 11pm PST/10c

Of course, all the accurate science in the world doesn’t help if you’re not telling an interesting story. But with such talented people working together, I think some optimism is justified. Let’s show the world that science and cinema are partners, not antagonists.

Posted in Entertainment, Science and Society | 45 Comments

How to Communicate on the Internet

Let’s say you want to communicate an idea X.

You would do well to simply say “X.”

Also acceptable is “X. Really, just X.”

A slightly riskier strategy, in cases where miscomprehension is especially likely, would be something like “X. This sounds a bit like A, and B, and C, but I’m not saying those. Honestly, just X.” Many people will inevitably start arguing against A, B, and C.

Under no circumstances should you say “You might think Y, but actually X.”

Equally bad, perhaps worse: “Y. Which reminds me of X, which is what I really want to say.”

For examples see the comment sections of the last couple of posts, or indeed any comment section anywhere on the internet.

It is possible these ideas may be of wider applicability in communication situations other than the internet.

(You may think this is just grumping but actually it is science!)

Posted in Humanity, Words | 23 Comments

Does Santa Exist?

There’s a claim out there — one that is about 95% true, as it turns out — that if you pick a Wikipedia article at random, then click on the first (non-trivial) link, and keep clicking on the first link of each subsequent article, you will end up at Philosophy. More specifically, you will end up at a loop that runs through Reality, Existence, Awareness, Consciousness, and Quality (philosophy), as well as Philosophy itself. It’s not hard to see why. These are the Big Issues, concerning the fundamental nature of the universe at a deep level. Almost any inquiry, when pressed to ever-greater levels of precision and abstraction, will get you there.

Does Santa Exist? Take, for example, the straightforward-sounding question “Does Santa Exist?” You might be tempted to say “No” and move on. (Or you might be tempted to say “Yes” and move on, I don’t know — a wide spectrum of folks seem to frequent this blog.) But even to give such a common-sensical answer is to presume some kind of theory of existence (ontology), not to mention a theory of knowledge (epistemology). So we’re allowed to ask “How do you know?” and “What do you really mean by exist?”

These are the questions that underlie an entertaining and thought-provoking new book by Eric Kaplan, called Does Santa Exist?: A Philosophical Investigation. Eric has a resume to be proud of: he is a writer on The Big Bang Theory, and has previously written for Futurama and other shows, but he is also a philosopher, currently finishing his Ph.D. from Berkeley. In the new book, he uses the Santa question as a launching point for a rewarding tour through some knotty philosophical issues. He considers not only a traditional attack on the question, using Logic and the beloved principles of reason, but sideways approaches based on Mysticism as well. (“The Buddha ought to be able to answer our questions about the universe for like ten minutes, and then tell us how to be free of suffering.”) His favorite, though, is the approach based on Comedy, which is able to embrace contradiction in a way that other approaches can’t quite bring themselves to do.

Most people tend to have a pre-existing take on the Santa question. Hence, the book trailer for Does Santa Exist? employs a uniquely appropriate method: Choose-Your-Own-Adventure. Watch and interact, and you will find the answers you seek.

Posted in Humor, Philosophy, Words | 15 Comments

The Evolution of Evolution: Gradualism, or Punctuated Equilibrium?

In some ways I’m glad I’m not an evolutionary biologist, even though the subject matter is undoubtedly fascinating and fundamental. Here in the US, especially, it’s practically impossible to have a level-headed discussion about the nature of evolutionary theory. Biologists are constantly defending themselves against absurd attacks from creationists and intelligent-design advocates. It can wear you down and breed defensiveness, which is not really conducive to carrying on a vigorous discussion about the state of that field.

But such discussions do exist, and are important. Here’s an interesting point/counter-point in Nature, in which respectable scientists argue over the current state of evolutionary theory: is it basically in good shape, simply requiring a natural amount of tweaking and updating over time, or is revolutionary re-thinking called for?

Illustration cichlids from different lakes, by R. Craig Albertson.

Illustration cichlids from different lakes, by R. Craig Albertson.

I’m a complete novice here, so my opinion should count for almost nothing. But from reading the two arguments, I tend to side with the gradualists on this one. As far as I can tell, the revolutionaries make their case by setting up a stripped-down straw-man version of evolution that nobody really believes (nor ever has, going back to Darwin), then proclaiming victory when they show that it’s inadequate, even though nobody disagrees with them. They want, in particular, to emphasize the roles of drift and development and environmental feedback — all of which seem worth emphasizing, but I’ve never heard anyone deny them. (Maybe I’m reading the wrong people.) And they very readily stoop to ad hominem psychoanalysis of their opponents, saying things like this:

Too often, vital discussions descend into acrimony, with accusations of muddle or misrepresentation. Perhaps haunted by the spectre of intelligent design, evolutionary biologists wish to show a united front to those hostile to science. Some might fear that they will receive less funding and recognition if outsiders — such as physiologists or developmental biologists — flood into their field.

Some might fear that, I guess. But I’d rather hear a substantive argument than be told from the start that I shouldn’t listen to those other folks because they’re just afraid of losing their funding. And the substantive arguments do exist. There’s no question that the theory of evolution is something that is constantly upgraded and improved as we better understand the enormous complexity of biological processes.

The gradualists (in terms of theory change, not necessarily in terms of how natural selection operates), by contrast, seem to make good points (again, to my non-expert judgment). Here’s what they say in response to their opponents:

They contend that four phenomena are important evolutionary processes: phenotypic plasticity, niche construction, inclusive inheritance and developmental bias. We could not agree more. We study them ourselves.

But we do not think that these processes deserve such special attention as to merit a new name such as ‘extended evolutionary synthesis’…

The evolutionary phenomena championed by Laland and colleagues are already well integrated into evolutionary biology, where they have long provided useful insights. Indeed, all of these concepts date back to Darwin himself, as exemplified by his analysis of the feedback that occurred as earthworms became adapted to their life in soil…

We invite Laland and colleagues to join us in a more expansive extension, rather than imagining divisions that do not exist.

Those don’t really read like the words of hidebound reactionaries who are unwilling to countenance any kind of change. It seems like a mistake for the revolutionaries to place so much emphasis on how revolutionary they are being, rather than concentrating on the subtle work of figuring out the relative importance of all these different factors to evolution in the real world — the importance of which nobody seems to deny, but the quantification of which is obviously a challenging empirical problem.

Fortunately physicists are never like this! It can be tough to live in a world of pure reason and unadulterated rationality, but someone’s got to do it.

Posted in Science | 30 Comments

Ten Questions for the Philosophy of Cosmology

Last week I spent an enjoyable few days in Tenerife, one of the Canary Islands, for a conference on the Philosophy of Cosmology. The slides for all the talks are now online; videos aren’t up yet, but I understand they are forthcoming.

Stephen Hawking did not actually attend our meeting -- he was at the hotel for a different event. But he stopped by for an informal session on the arrow of time. Photo by Vishnya Maudlin.

Stephen Hawking did not actually attend our meeting — he was at the hotel for a different event. But he stopped by for an informal session on the arrow of time. Photo by Vishnya Maudlin.

It was a thought-provoking meeting, but one of my thoughts was: “We don’t really have a well-defined field called Philosophy of Cosmology.” At least, not yet. Talks were given by philosophers and by cosmologists; the philosophers generally gave good talks on the philosophy of physics, while some of the cosmologists gave solid-but-standard talks on cosmology. Some of the other cosmologists tried their hand at philosophy, and I thought those were generally less successful. Which is to be expected — it’s a sign that we need to do more work to set the foundations for this new subdiscipline.

A big part of defining an area of study is deciding on a set of questions that we all agree are worth thinking about. As a tiny step in that direction, here is my attempt to highlight ten questions — and various sub-questions — that naturally fall under the rubric of Philosophy of Cosmology. They fall under other rubrics as well, of course, as well as featuring significant overlap with each other. So there’s a certain amount of arbitrariness here — suggestions for improvements are welcome.

Here we go:

  1. In what sense, if any, is the universe fine-tuned? When can we say that physical parameters (cosmological constant, scale of electroweak symmetry breaking) or initial conditions are “unnatural”? What sets the appropriate measure with respect to which we judge naturalness of physical and cosmological parameters? Is there an explanation for cosmological coincidences such as the approximate equality between the density of matter and vacuum energy? Does inflation solve these problems, or exacerbate them? What conclusions should we draw from the existence of fine-tuning?
  2. How is the arrow of time related to the special state of the early universe? What is the best way to formulate the past hypothesis (the early universe was in a low entropy state) and the statistical postulate (uniform distribution within macrostates)? Can the early state be explained as a generic feature of dynamical processes, or is it associated with a specific quantum state of the universe, or should it be understood as a separate law of nature? In what way, if any, does the special early state help explain the temporal asymmetries of memory, causality, and quantum measurement?
  3. What is the proper role of the anthropic principle? Can anthropic reasoning be used to make reliable predictions? How do we define the appropriate reference class of observers? Given such a class, is there any reason to think of ourselves as “typical” within it? Does the prediction of freak observers (Boltzmann Brains) count as evidence against a cosmological scenario?
  4. What part should unobservable realms play in cosmological models? Does cosmic evolution naturally generate pocket universes, baby universes, or many branches of the wave function? Are other “universes” part of science if they can never be observed? How do we evaluate such models, and does the traditional process of scientific theory choice need to be adapted to account for non-falsifiable predictions? How confident can we ever be in early-universe scenarios such as inflation?
  5. What is the quantum state of the universe, and how does it evolve? Is there a unique prescription for calculating the wave function of the universe? Under what conditions are different parts of the quantum state “real,” in the sense that observers within them should be counted? What aspects of cosmology depend on competing formulations of quantum mechanics (Everett, dynamical collapse, hidden variables, etc.)? Do quantum fluctuations happen in equilibrium? What role does decoherence play in cosmic evolution? How does do quantum and classical probabilities arise in cosmological predictions? What defines classical histories within the quantum state?
  6. Are space and time emergent or fundamental? Is quantum gravity a theory of quantized spacetime, or is spacetime only an approximation valid in a certain regime? What are the fundamental degrees of freedom? Is there a well-defined Hilbert space for the universe, and what is its dimensionality? Is time evolution fundamental, or does time emerge from correlations within a static state?
  7. What is the role of infinity in cosmology? Can the universe be infinitely big? Are the fundamental laws ultimate discrete? Can there be an essential difference between “infinite” and “really big”? Can the arrow of time be explained if the universe has an infinite amount of room in which to evolve? Are there preferred ways to compare infinitely big subsets of an infinite space of states?
  8. Can the universe have a beginning, or can it be eternal? Does a universe with a first moment require a cause or deeper explanation? Are there reasons why there is something rather than nothing? Can the universe be cyclic, with a consistent arrow of time? Could it be eternal and statistically symmetric around some moment of lowest entropy?
  9. How do physical laws and causality apply to the universe as a whole? Can laws be said to change or evolve? Does the universe as a whole maximize some interesting quantity such as simplicity, goodness, interestingness, or fecundity? Should laws be understood as governing/generative entities, or are they just a convenient way to compactly represent a large number of facts? Is the universe complete in itself, or does it require external factors to sustain it? Do the laws of physics require ultimate explanations, or can they simply be?
  10. How do complex structures and order come into existence and evolve? Is complexity a transient phenomenon that depends on entropy generation? Are there general principles governing physical, biological, and psychological complexity? Is the appearance of life likely or inevitable? Does consciousness play a central role in accounting for the universe?

Chances are very small that anyone else interested in the field, forced at gunpoint to pick the ten biggest questions, would choose exactly these ten. Such are the wild and wooly early days of any field, when the frontier is unexplored and the conventional wisdom has yet to be settled. Feel free to make suggestions.

Posted in Philosophy, Science | 64 Comments

Planck Speaks: Bad News for Primordial Gravitational Waves?

Ever since we all heard the exciting news that the BICEP2 experiment had detected “B-mode” polarization in the cosmic microwave background — just the kind we would expect to be produced by cosmic inflation at a high energy scale — the scientific community has been waiting on pins and needles for some kind of independent confirmation, so that we could stop adding “if it holds up” every time we waxed enthusiastic about the result. And we all knew that there was just such an independent check looming, from the Planck satellite. The need for some kind of check became especially pressing when some cosmologists made a good case that the BICEP2 signal may very well have been dust in our galaxy, rather than gravitational waves from inflation (Mortonson and Seljak; Flauger, Hill, and Spergel).

Now some initial results from Planck are in … and it doesn’t look good for gravitational waves. (Warning: I am not a CMB experimentalist or data analyst, so take the below with a grain of salt, though I tried to stick close to the paper itself.)

Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes
Planck Collaboration: R. Adam, et al.

The polarized thermal emission from Galactic dust is the main foreground present in measurements of the polarization of the cosmic microwave background (CMB) at frequencies above 100GHz. We exploit the Planck HFI polarization data from 100 to 353GHz to measure the dust angular power spectra CEE,BBℓ over the range 40<ℓ<600. These will bring new insights into interstellar dust physics and a precise determination of the level of contamination for CMB polarization experiments. We show that statistical properties of the emission can be characterized over large fractions of the sky using Cℓ. For the dust, they are well described by power laws in ℓ with exponents αEE,BB=−2.42±0.02. The amplitudes of the polarization Cℓ vary with the average brightness in a way similar to the intensity ones. The dust polarization frequency dependence is consistent with modified blackbody emission with βd=1.59 and Td=19.6K. We find a systematic ratio between the amplitudes of the Galactic B- and E-modes of 0.5. We show that even in the faintest dust-emitting regions there are no "clean" windows where primordial CMB B-mode polarization could be measured without subtraction of dust emission. Finally, we investigate the level of dust polarization in the BICEP2 experiment field. Extrapolation of the Planck 353GHz data to 150GHz gives a dust power ℓ(ℓ+1)CBBℓ/(2π) of 1.32×10−2μK2CMB over the 40<ℓ<120 range; the statistical uncertainty is ±0.29 and there is an additional uncertainty (+0.28,-0.24) from the extrapolation, both in the same units. This is the same magnitude as reported by BICEP2 over this ℓ range, which highlights the need for assessment of the polarized dust signal. The present uncertainties will be reduced through an ongoing, joint analysis of the Planck and BICEP2 data sets.

We can unpack that a bit, but the upshot is pretty simple: Planck has observed the whole sky, including the BICEP2 region, although not in precisely the same wavelengths. With a bit of extrapolation, however, they can use their data to estimate how big a signal should be generated by dust in our galaxy. The result fits very well with what BICEP2 actually measured. It’s not completely definitive — the Planck paper stresses over and over the need to do more analysis, especially in collaboration with the BICEP2 team — but the simplest interpretation is that BICEP2’s B-modes were caused by local contamination, not by early-universe inflation.

Here’s the Planck sky, color-coded by amount of B-mode polarization generated by dust, with the BICEP2 field indicated at bottom left of the right-hand circle:

planckdustmap

Every experiment is different, so the Planck team had to do some work to take their measurements and turn them into a prediction for what BICEP2 should have seen. Here is the sobering result, expressed (roughtly) as the expected amount of B-mode polarization as a function of angular size, with large angles on the left. (Really, the BB correlation function as a function of multipole moment.)

planck-bmode-spectrum

The light-blue rectangles are what Planck actually sees and attributes to dust. The black line is the theoretical prediction for what you would see from gravitational waves with the amplitude claimed by BICEP2. As you see, they match very well. That is: the BICEP2 signal is apparently well-explained by dust.

Of course, just because it could be dust doesn’t mean that it is. As one last check, the Planck team looked at how the amount of signal they saw varied as a function of the frequency of the microwaves they were observing. (BICEP2 was only able to observe at one frequency, 150 GHz.) Here’s the result, compared to a theoretical prediction for what dust should look like:

planck-dust-spectrum

Again, the data seem to be lining right up with what you would expect from dust.

It’s not completely definitive — but it’s pretty powerful. BICEP2 did indeed observe the signal that they said they observed; but the smart money right now is betting that the signal didn’t come from the early universe. There’s still work to be done, and the universe has plenty of capacity for surprising us, but for the moment we can’t claim to have gathered information from quite as early in the history of the universe as we had hoped.

Posted in arxiv, Science | 55 Comments