Guest Post: Doug Finkbeiner on Fermi Bubbles and Microwave Haze

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When it comes to microwaves from the sky, the primordial cosmic background radiation gets most of the publicity, while everything that originates nearby is lumped into the category of “foregrounds.” But those foregrounds are interesting in their own right; they tell us about important objects in the universe, like our own galaxy. For nearly a decade, astronomers have puzzled over a mysterious hazy glow of microwaves emanating from the central region of the Milky Way. More recently, gamma-ray observations have revealed a related set of structures known as “Fermi Bubbles.” We’re very happy to host this guest post by Douglas Finkbeiner from Harvard, who has played a crucial role in unraveling the mystery.

Planck, Gamma-ray Bubbles, and the Microwave Haze

“Error often is to be preferred to indecision” — Aaron Burr, Jr.

Among the many quotes that greet a visitor to the Frist Campus Center at Princeton University, this one is perhaps the most jarring. These are bold words from the third Vice President of the United States, the man who shot Alexander Hamilton in a duel. Yet they were on my mind as a postdoc in 2003 as I considered whether to publish a controversial claim: that the microwave excess called the “haze” might originate from annihilating dark matter particles. That idea turned out to be wrong, but pursuing it was one of the best decisions of my career.

In 2002, I was studying the microwave emission from tiny, rapidly rotating grains of interstellar dust. This dust spans a range of sizes from microscopic flecks of silicate and graphite, all the way down to hydrocarbon molecules with perhaps 50 atoms. In general these objects are asymmetrical and have an electric dipole, and a rotating dipole emits radiation. Bruce Draine and Alex Lazarian worked through this problem at Princeton in the late 1990s and found that the smallest dust grains can rotate about 20 billion times a second. This means the radiation comes out at about 20 GHz, making them a potential nuisance for observations of the cosmic microwave background. However, by 2003 there was still no convincing detection of this “spinning dust” and many doubted the signal would be strong enough to be observed.

The haze

In February 2003, the Wilkinson Microwave Anisotropy Probe (WMAP) team released their first results. …

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Animal Consciousness

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At the Francis Crick Memorial Conference in Cambridge last month, a collection of internationally recognized experts on consciousness took an unusual step, as science conferences go: they issued a declaration (pdf). The subject was whether or not non-human animals could be considered “conscious.” (See discussion by Octopus Chronicles, Christof Koch, io9.) The spirit of the declaration was in the direction of saying “pretty much, yeah,” although they tried to stick to what could be scientifically discussed. Here’s the upshot of the declaration:

The absence of a neocortex does not appear to preclude an organism from experiencing affective states. Convergent evidence indicates that non-human animals have the neuroanatomical, neurochemical, and neurophysiological substrates of conscious states along with the capacity to exhibit intentional behaviors. Consequently, the weight of evidence indicates that humans are not unique in possessing the neurological substrates that generate consciousness. Nonhuman animals, including all mammals and birds, and many other creatures, including octopuses, also possess these neurological substrates.

Even the experts don’t necessarily agree on a definition of “consciousness,” so the declaration doesn’t come right out and say “animals are conscious.” But the authors basically agree that the mental supervenes on the physical, so whatever consciousness may be, it must have some neurological substrate — some parts of the brain that do the work. The point they’re making is, whatever those parts are, some animals have them too.

I don’t have a well-thought-out position on this, at least as far as the big-picture consequences are concerned. …

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arXiv Find: Reasons Not to Believe in the String Theory Landscape

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Tom Banks has long been skeptical of the popular picture of the string theory landscape — the idea that there is some extremely large (10500 or more) number of phases of string theory, representing different ways to compactify the extra dimensions, and that all these phases are dynamically connected to each other, possibly by cosmological transitions during eternal inflation. Tom’s reasons aren’t of the curmudgeonly you-kids-get-off-my-lawn sort, but arise from his views about how quantum gravity works. (He thinks different cosmological boundary conditions represent truly different quantum theories, not just different regions of one big spacetime.) Well worth considering, if only because it’s too easy to run off in the direction of conventional wisdom when you’re far away from the realm of experimental testing.

The Top 10500 Reasons Not to Believe in the Landscape

T. Banks

The String Landscape is a fantasy. We actually have a plausible landscape of minimally supersymmetric $AdS_4$ solutions of supergravity modified by an exponential superpotential. None of these solutions is accessible to world sheet perturbation theory. If they exist as models of quantum gravity, they are defined by conformal field theories, and each is an independent quantum system, which makes no transitions to any of the others. This landscape has nothing to do with CDL tunneling or eternal inflation.

A proper understanding of CDL transitions in QFT on a fixed background dS space, shows that the EI picture of this system is not justified within the approximation of low energy effective field theory. The cutoff independent physics, defined by the Euclidean functional integral over the 4-sphere admits only a finite number of instantons. Plausible extensions of these ideas to a quantum theory of gravity obeying the holographic principle explain all of the actual facts about CDL transitions in dS space, and lead to a picture radically different from eternal inflation.

Theories of Eternal Inflation (EI) have to rely too heavily on the anthropic principle to be consistent with experiment. Given the vast array of effective low energy field theories that could be produced by the conventional picture of the string landscape one is forced to conclude that the most numerous anthropically allowed theories will disagree with experiment violently.

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Guest Post: Terry Rudolph on Nature versus Nurture

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Everyone always wants to know whether the wave function of quantum mechanics is “a real thing” or whether it’s just a tool we use to calculate the probability of measuring a certain outcome. Here at CV, we even hosted a give-and-take on the issue between instrumentalist Tom Banks and realist David Wallace. In the latter post, I linked to recent preprint on the issue that proved a very interesting theorem, seemingly boosting the “wave functions are real” side of the debate.

That preprint was submitted to Nature, but never made it in (although it did ultimately get published in Nature Physics). The story of why such an important result was shunted away from the journal to which it was first submitted (just like Peter Higgs’s paper where he first mentioned the Higgs boson!) is interesting in its own right. Here is that story, as told by Terry Rudolph, an author of the original paper. Terry is a theoretical physicist at Imperial College London, who “will work on anything that has the word `quantum’ in front of it.”

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There has long been a tension between the academic publishing process, which is slow but which is still the method by which we certify research quality, and the ability to instantaneously make one’s research available on a preprint server such as the arxiv, which carries essentially no such certification whatsoever. It is a curious (though purely empirical) observation that the more theoretical and abstract the field the more likely it is that the all-important question of priority – when the research is deemed to have been time-stamped as it were – will be determined by when the paper first appeared on the internet and not when it was first submitted to, or accepted by, a journal. There are no rules about this, it’s simply a matter of community acceptance.

At the high-end of academic publishing, where papers are accepted from extremely diverse scientific communities, prestigious journals need to filter by more than simply the technical quality of the research – they also want high impact papers of such broad and general interest that they will capture attention across ranges of scientific endeavour and often the more general public as well. For this reason it is necessary they exercise considerably more editorial discretion in what they publish.

Topics such as hurdling editors and whether posting one’s paper in preprint form impacts negatively the chances of it being accepted at a high-end journal are therefore grist for the mill of conversation at most conference dinners. In fact the policies at Nature about preprints have evolved considerably over the last 10 years, and officially they now say posting preprints is fine. But is it? And is there more to editorial discretion than the most obvious first hurdle – namely getting the editor to send the paper to referees at all? If you’re a young scientist without experience of publishing in such journals (I am unfortunately only one of the two!) perhaps the following case study will give you some pause for thought.

Last November my co-authors and I bowed to some pressure from colleagues to put our paper, then titled The quantum state cannot be interpreted statistically, on the arxiv. We had recently already submitted it to Nature because new theorems in the foundations of quantum theory are very rare, and because the quantum state is an object that cuts across physics, chemistry and biology – so it seemed appropriate for a broad readership. Because I had heard stories about the dangers of posting preprints so many times I wrote the editor to verify it really was ok. We were told to go ahead, but not to actively participate in or solicit pre-publication promotion or media coverage; however discussing with our peers, presenting at conferences etc was fine.

Based on the preprint Nature themselves published a somewhat overhyped pop-sci article shortly thereafter; to no avail I asked the journalist concerned to hold off until the status of the paper was known. We tried to stay out of the ensuing fracas – is discussing your paper on blogs a discussion between your peers or public promotion of the work?

…

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Morality and Basketball

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Zach Weinersmith (of) put up a blog post about the subjective nature of morality, which I tweeted approvingly. But afterward I realized that, while our substantive views are pretty much in agreement, I sometimes use a very similar-sounding analogy as the one he invoked, but in the precisely opposite sense!

Zach’s analogy is the following: “objective” morality is to subjective morality as the rules of basketball are to the rules of Pankration, an ancient Greek free-for-all fighting competition. That is, in basketball, we have rules that are handed down from on high (the NBA or some other governing body), just as we do with objective morality (God or the nature of the universe or some such thing). In Pankration, while there are no formal rules, there are patterns that evolve due to the nature of the game; i.e., go for the fingers and other easily-damaged parts of the body. These kinds of rules are different, of course, but they do come into being over time.

That’s fine as far as it goes, but I like to use the basketball analogy to make a different point. I don’t believe in objective morality; the universe just is, and there’s nothing “out there” that judges human behaviors to be good or bad. These categories of good and bad are things we human beings invent. And in that sense, in my version of the analogy, the rules of morality are exactly like the rules of basketball! The difference is that I’m not analogizing the NBA to God or the universe, I’m analogizing the NBA to a collection of human beings that make up rules (which is a pretty exact analogy, really).

The point is this: the rules of basketball were not handed down by God, nor are they inherent in the structure of the universe. They were invented by James Naismith and others, and fine-tuned over time. We could invent different rules, and we wouldn’t be making a “mistake” in the sense we’re making a mistake if we think the universe was created 6,000 years ago. We’d just be choosing to play a different game.

The crucial part, however, is that the rules of basketball are not arbitrary, either. They are subjective in the sense that we can make them be whatever we want, but they are non-arbitrary in the sense that some rules “work better” than others. That’s pretty obvious when you hear basketball fans arguing about the proper distance for the three-point line, or the niceties of hand-checking or goaltending, or when a crossover dribble is ruled to be traveling. People don’t merely shrug their shoulders and say “eh, it doesn’t matter, the rules are whatever, as long as they are fairly enforced.” The rules do matter, even though the choice of what they are is ultimately in our hands.

That’s because we have a goal when we invent the rules of basketball: to create the most fair and entertaining game. The distance to the three-point line is very finely calibrated so that it’s far enough away to be a challenge for NBA-level talent, but close enough that it’s a valuable shot to take under the right circumstances. “Subjective” (or “invented”) doesn’t mean “arbitrary.”

Likewise for morality. The rules of morality are ultimately human constructs. But they’re not arbitrary constructs: we invent them to serve certain purposes. People are not blank slates; they have desires, preferences, aspirations. We mostly want to be nice to each other, be happy, live fairly, and other aspects of folk morality. The rules of morality we invent are attempts to systematize and extend these simple goals into a rigorous framework that can cover as many circumstances as possible in an unambiguous way.

And what if someone doesn’t agree with our folk morality or the systematization thereof? What if someone wants to bring some Calvinball to our pickup game? We do the same thing we’d do in basketball: we penalize them. We call a foul, or traveling, or just refuse to play with them. And we don’t need to invoke God or the laws of nature to do it. It’s true that we made up the rules, but they are no less enforceable for it.

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A Few Powers of Ten

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Via the endlessly enjoyable It’s Okay to Be Smart, here’s a gif image that zooms in by about three orders of magnitude. (Not sure of the original source.) We start by looking at an amphipod, a tiny shrimplike critter about a millimeter across. For some reason (vanity?) it’s decorated by an even tinier diatom, a bit of algae that is common in phytoplankton. From there we zoom in on a yet-tinier bacterium, just chilling out near the middle of the diatom.

Human beings have about ten times as many bacterial cells inside them as “human” cells. The bacteria are the passengers, we’re just the bus.

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Gravitational Waves in Five Years

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LIGO, the gravitational-wave observatory, is currently on ice. After running successfully (although without actually detecting any gravitational waves) through 2007, it got a mini-upgrade and ran as Enhanced LIGO in 2009 and 2010. But in October 2010 it shut off, and the original detectors were disassembled. Not because anything was wrong, but because of a long-anticipated upgrade to Advanced LIGO, a substantially more sensitive observatory.

Those upgrades are still going on, with the new detectors scheduled to come online in 2014. Advanced LIGO should provide more than a tenfold improvement in sensitivity, which allows the search for gravitational waves to pass an important threshold: with LIGO, it would have been possible but quite fortunate to actually detect gravitational waves from predicted astrophysical sources. With Advanced LIGO, it will be a surprise if we don’t detect them.

Clara Moskowitz has nice update on MSNBC.com. She quotes Kip Thorne as predicting that our first definite direct detection of gravitational waves will come in between 2014 and 2017 — within five years. Start your betting markets! Traditionally, looking at the skies in a new way (radio waves, cosmic rays, X-rays, gamma rays, neutrinos…) has always taught us something new and exciting. I’d be surprised if gravitational waves aren’t equally surprising.

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Chatting Atheism

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I took part in a conversation about contemporary atheism, which appeared on The Point, which is a web series spin-off of The Young Turks, which itself is both a web series and a show broadcast on Current TV. (Got all that?) My co-panelists were Michael Shermer of the Skeptics Society and Edward Falzon, author of the (satirical!) book Being Gay is Disgusting, and it was hosted by Cara Santa Maria, science correspondent for the Huffington Post.

Atheists On Religion, Science, And Morality (The Point)

The format of the show is that we hear three very brief pre-recorded “points,” to which the panelists then respond. In this case, all the points and all the panelists were already confirmed atheists, so we could put aside for the moment the endless arguments about whether God exists and focus on the very interesting questions of what to do about the fact that he doesn’t. The points we heard were from James Randi, PZ Myers, and AJ Johnson of American Atheists. I wasn’t familiar with AJ before this event, but her video was very strong; I think (hope) we’ll be hearing a lot more from her in the future.

It was a great talk, although it did reinforce my conviction that while we atheists are mostly right on the metaphysics, we need to really raise our game when it comes to epistemology and metaethics.

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