Archive for: February, 2011

I was put on this Earth as a warning to others

Feb 27 2011 Published by under Gratuitous, Random & Gratuitous

Friday morning, while flossing my teeth, I had intended to tweet about it.

Fortunately, I got caught up thereafter with things like making my lunch and grading quantum homework. But, still, for a period of at least several minutes, I intended to broadcast to twitter about flossing my teeth.

To make things worse, I'm now blogging about it.

If I look behind me and downwards, I can see the shark.

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"More Things in Heaven and Earth" -- the interaction of physics and astronomy

365 Days of Astronomy is a daily podcast about astronomy, entirely recorded by volunteers. The topics are all over the place; some are about amateur astronomy, some are about the history of astronomy, some are about recent discoveries in astronomy. I've done a number of these over the last couple of years, and am doing more this year.

I recorded today's podcast— and, if I am to be perfectly honest, I have to admit I recorded yesterday, way after when I was supposed to get it in. The topic is the interaction between fundamental physics and astronomy. I talk a little about ancient physics, where the realm outside the sky and the Earth were viewed to be separate realms. Newton's universal gravitation unified those two realms. Some chemical elements were discovered originally in astronomical objects, and it was from observations of astronomical objects that we learned about neutrino oscillations.

You can check out today's entry if you want to hear more.

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How likely do you think it is that is right?

Over at Cosmic Variance, Sean Carroll has a post entitled Do You Think Inflation Probably Happened?. In it, he talks about several speculative ideas in cosmology and particle physics that are there to explain certain unexplained things, but for which there's not direct experimental evidence. Being a bit of a narcissist, I decided to blather on a blog post about this rather than just comment on the comment thread there.

One thing I do want to note before I dive in: all of these theories are different from things like the theory of General Relativity or the theory of biological evolution. Those two theories have tremendous direct support for them, so we believe that they are true. These theories, though, often aren't even theories, but are "paradigms", "ideas", "hypotheses", or things like that. For all of them there are good reasons to think that they might be true, but they're lacking direct solid evidence.

1. Inflation

This is the idea that 13.7 billion years ago, about 10 or so minutes before the epoch of Big-Bang nucleosynthesis, there was a period of at least a tiny fraction of a second (but potentially as long as "forever") the Universe was expanding exponentially. During this time, the Universe expanded by at least a factor of 1024 or so (Agullo et al. 2009). Inflation was invented to explain problems such as why the Cosmic Microwave Background is at the same temperature across the sky, even though things more than a degree or so apart on the sky hadn't had time since the beginning of the Universe to send light signals to each other and be able to equilibrate with each other.

I would estimate the probability that inflation really happened at about 80% or so, which makes me feel very non-conservative. However, the paradigm does explain a lot, and there are even details in recent cosmic microwave background results that fit with the idea.

2. Supersymmetry

I'm gonna go 50% here, mostly because I am ignorant. I know the basic idea of supersymmetry. However, I have to admit that I'm not conversant enough with Quantum Field Theory to understand the reasons why it's compelling. I do know that people who think a lot about this think that it is compelling, and think that it ought to be out there, or at least that it's reasonable that it's out there, which is why I rate this as high as 50%. It's a matter of trusting their judgment, but not having a great basis myself to form an opinion.

3. String Theory

String Theory remains our leading candidate for unifying gravity with the standard model of particle physics. Physics is in this weird situation where it has two extremely successful theories that have withstood every test they've been put to. One is General Relativity (GR), the other is the Standard Model of Particle Physics (SMPP)— which is built on top of Quantum Field Theory, the special relativistic version of Quantum Mechanics. However, the two don't play nice together. Most of the time, this doesn't matter. In realms where GR is important, that is where gravity is strong, quantum effects are negligible. On tiny scales where you have to worry about Quantum Mechanics, gravity is negligible. However, when densities get high enough (such as at the center of a black hole or in the very early Universe), you need to use both, and when you try you get nonsensical answers.

We haven't experimentally been able to probe these regions, however. It's very weird to have two theories that stand up to every experiment or observation we can make, but which we know, for theoretical reasons, can't both be right.

String theory is our leading candidate for unifying the two. I don't understand string theory beyond the Elegant Universe level. And, indeed, you can find some high-end physicists who have come out with an "anti-String Theory" stance, arguing that a few decades of effort haven't paid off and that too much intellectual capital is now wasted on it.

I'm enough of an iconoclast to be dubious of String Theory, although without really good reason. Part of that is that I find General Relativity much more aesthetically pleasing than Quantum Field Theory, which includes some ugly bits in it (like renormalization). However, if I'm to be honest, I'll have to say that a decent fraction for that reason is that I understand GR better than QFT, so this isn't a fair judgment. Still, part of me wants GR to be "more right" than QFT, so that the former won't have to be as modified to make them play together. So, for these unscientific and poor reasons, I'm only going to rate the probability that String Theory is right at about 15%.

4. Some Form of Higgs Boson

My understanding of the Higgs Mechanism is weak. Somehow, the Higgs Boson is the particle that "gives things mass". Basically, all massive particles couple with the Higgs Field, and the energy of that coupling is what gives them their inertial mass. (It would be more fun if we called the Higgs Field the Molasses Field, but what can you do.) I think (but am not sure) that the need for a Higgs field is the result of electroweak unification, and that's a rather successful theory. Indeed, I think it can be said that the W+, W-, and Z particles are three components of a four (at least?) component Higgs field, so in a sense we already have seen part of the Higgs field.

Again, I'm speaking from not knowing as much as I ought to here, but I have the sense that this whole Higgs business is fairly well established, so I'm going to give you a 75% probability that they're out there, and that we'll find them soon. It would be cool if it's not out there, because it means we've finally found something that doesn't work with the Standard Model.... However, it would be uncool if it's not out there and the LHC doesn't find anything bold and new beyond the Standard Model, because that would make it very difficult to maintain public interest in particle physics.

5. Large Extra Dimensions

Damn, I think it would be really cool if these existed. However, I am going to have to go with a low value of 10% for these. Sure, it's possible, but I have yet to be convinced that there's really any good reason beyond "boy, that would be cool" to think that they exist.

6. WIMP Dark Matter

In answering this question, I have to weasel a bit because I'm not sure what is meant by WIMP. How specific is that? Would (say) a sterile neutrino count as a WIMP? A sterile neutrino is one that doesn't interact via the weak force because it's got the wrong chirality, so technically, it's not a WIMP (since the WI means "Weakly Interacting"). But, it is nonbaryonic mass.

My confidence in nonbaryonic dark matter is extremely high -- I'd place that at something like 98%. We've seen it. Not directly, but we've seen it indirectly just as assuredly as humanity had seen the neutrino indirectly before its direct experimental confirmation in 1956 (Cowan et al. 1956).

But is it something that's Weakly Interacting? I guess I'd have to place that at more like 60%. I'll only be mildly surprised if it turns out that the Dark Matter we know exists doesn't interact via the Weak Force.

7. Any non-cosmological-constant explanation for cosmic acceleration

It makes me sad to say this, but I'd place this at a mere 25%. It would be so much more interesting if it's something other than just a cosmological constant (which is another word for vacuum energy). Especially if it's "phantom dark energy", whose density increases with time, as that would mean that eventually we'll reach a period where the Universe is expanding at the same rate it was during inflation, giving us a nice bookend sort of symmetry for the beginning and end of the Universe. But, this is a case where my gut instinct and my aesthetic desires are at odds. I've thought for five or six years that experiments that try to nail down the equation of state parameter for Dark Energy will just keep shrinking the error bars around the vacuum energy value, never able to either prove or rule out that its vacuum energy. (If the error bars shrink enough and the value is off of the vacuum energy value, then we'd rule it out. But, if they just shrink around that value, we can't rule it out, but we can't be sure that it's just little enough different that we aren't able to yet see the difference.)

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Archives imported

Feb 06 2011 Published by under About the Blog

When this blog opened here on scientopia, it already had the archives from my stint at scienceblogs. I've now imported the archive from the blog between the scienceblogs era and the scientopia era.

I fear that the posts from the pre-scienceblogs era are lost to the mists of history. Other than those, however, this site now has the full archives of my blog.

At some point, I'll probably try to clean up the categories. As a result of the multiple imports, there are redundant categories, and the hierarchy is rather disjointed.

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Online talk tomorrow morning : "Neutrino: Placeholder Particle"

I'll be giving a talk in Second Life tomorrow morning at 10AM pacific time. (That's Saturday, Feb 5, at 18:00 UT.) This is part of a regular talk series; follow that link to find the slides and audio recordings from most of the previous talks I've given in the series. Remember that a Second Life account is free! Come and hear the talk. You can also ask questions in text chat, which I generally try to respond to as the talk is ongoing.

Tomorrow's talk is entitled "Neutrino: Placeholder Particle". I'll talk about the history of the discovery of the neutrino. Even Pauli, the guy who proposed the neutrino, was uncomfortable with making up a new particle that nobody had seen to explain things that seemed to be missing from other observations. There are clear parallels to Dark Matter today, with many being uncomfortable that we've got most of the Universe made out of stuff that we can't identify. I'll also talk about our current state of knowledge of the neutrino, and I hope to get into the issue of how the "mass neutrinos" are not the same as the "flavor neutrinos", and even though there are three of each, there are still only three total neutrinos. (It's a Schrödingers Cat sort of thing.)

Here's the abstract I sent to Paradox Olbers, the organizer of the MICA talks:

Sometimes critics of nonbaryonic dark matter will characterize it as a "placeholder particle"-- the name we give to the fact that we can't find particles doing the things that we see happening gravitationally. Of course, dark matter is not new in astronomy; Uranus, for instance, was originally detected indirectly. Nor are palceholder particles new in particle physics. The neutrino was originally proposed more than 20 years before it was first observed. In this talk, I'll go over the history of our discovery of the neutrino, and how it was in fact astronomy that led to some relatively recent important discoveries about these elusive little particles.

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Why I don't like the term "Gnu Atheist"

You will say that a group has the right to call themselves whatever they want, and you will be right. I just wish they hadn't chosen that term. It extends this group's screwing up cultural battles that don't need to be fought into yet another realm I care deeply about, and as with the first, it can only make things harder and more complicated.

Who are the "gnu atheists"? Well, first, a word of warning. If you try to define them, they show up and accuse you of choosing a definition for purposes of setting up a straw man. However, most of those in the movement formerly known as "New Atheism" seem to share the following characteristics. They are atheists. They believe the world would be a better place if religion would go away, becoming nothing more than cultural history and cultural tradition. They think that any religion that claims to be anything other than just cultural tradition is incompatible with science and the scientific world view. They believe that if somebody aims to accept science and is intellectually honest and consistent, the success of modern science must necessarily lead that person to accept philosophical materialism. They use the word "reason" as a synonym for "application of scientific reasoning", thereby making anybody who is religious by definition guilty of thinking without reason. (As well as a lot of other people, for instance all faculty at a University who aren't in a science or engineering department, but they tend either not to realize that they're doing it, or to downplay that.)

Beyond that, a subset of them are incredibly strident and combative. They think that any religion at all is a threat to science. They do not hesitate to call non-atheists idiots or childish. They will crap the comment threads of posts like this one with all sorts of (frankly) bigotry hiding under the clothing of assumed "reason", citing the names of logical fallacies the way fundamentalists cite scripture. They will assert that they know the Truth and that therefore it's perfectly justified for them to say frankly insulting things, and then say that others shouldn't be offended by the Truth. They seem to think that non-fundamentalist theists are prevaricators who "pick and choose" from their religion, and thus are somehow misrepresenting their own religious beliefs. I generally think that this is because they'd prefer to argue against fundamentalists, for it's extremely easy to show how fundamentalists are at odds with science. But, it's very disheartening to see somebody who wants people to accept science then criticizing a theist for not being a fundamentalist. It is the behavior of this subset that leads me to the conclusion that "fundamentalist atheist" is the best term for this sort of atheist. Most atheists, thankfully, are not like this, but there is the subset that argues that their philosophy is the only philosophy that can be accepted by reasonable people who accept science— much as fundamentalist Christians argue that their philosophy is the only philosophy that can be accepted by people who are good and "saved".

What is the first cultural battle that these "gnu atheists" make more difficult? Well, obviously, the whole religion/science debate. Given that a substantial fraction of the USA is religious and values their religion, it should be pretty bloody obvious that if self-styled defenders of science are out there saying that science is incompatible with religion, it is only going to put up more barriers against the bulk of the population accepting science. Of course, sometimes obvious things are wrong— quantum mechanics is full of examples. And the new atheists are fond of pointing this out, arguing that there is no evidence that what they're doing is harmful. Of course, there's also no evidence that what they're doing is helpful... but they don't seem to think that a lack of evidence coupled with what is obvious disrespect and very plausibe harm is enough for them to question their behavior. What's more, when you do present evidence, they will often dismiss it as anecdotal, or not clear statistical evidence, or not enough evidence, in a manner that frankly reminds me of this comment on Phil Plait's blog by a creationist who insists that without complete timeline of all mutations in evolution, one shouldn't accept evolution. (Aside: despite having the same first name, I did not write that comment!)

These "gnu atheists" will attack defenders of science such as the Chris Mooney & Sheril Kirshbaum, or Josh Rosenau, for pointing out the obvious harm that their tactics could do to our shared cause. They will argue that the National Center for Science Education shouldn't be saying that science and religion are compatible, because if they're really about "science" they shouldn't be saying anything about religion at all. This last tactic is particularly annoying, because of course they themselves will not hesitate to go out and say that science is incompatible with religion. After all, the way that they've defined things, they're just telling the truth, and anybody who claims to defend science and says that religion might be OK is venturing into off-limits territory. They will reject empirical evidence that religion and science are compatible— specifically, that huge numbers of working scientists are themselves religious— on the basis that it is incompatible with their philosophy, and therefore non-atheist scientists have something wrong with them (they're "compartmentalizing", or "intellectually dishonest", or some such).

So. We've got a cause that a lot of us care deeply about— mainstream acceptance of science, scientific reasoning, and the scientific method. We have those out there— fundamentalists of various religions, most obviously— who want to reject much of science, and who have a distressingly powerful voice in public political discourse. And, we've got a broad population who are religious and care about their religion, but who are capable of accepting science. Then, we have a subset of those arguing for science who also argue that accepting science means having to reject religion... which of course provides direct support for the fundamentalists who argue that scientists are cultural warriors trying to take away everybody's religion. That's not true, but the fact that some scientists are out there saying that makes it much harder for people like the NCSE to argue that the scientific establishment really doesn't want to destroy religion.

In other words, I'm annoyed at the "gnu atheists" in the first place; not just because many are so blinded by their love for their own philosophy that they can't see that it isn't necessarily objective truth, and not just because many are frankly rude and insulting while thinking there must be something wrong with me if I find them rude and insulting. I'm annoyed at them also because they're getting in the way of a cause I care about, mainstream acceptance of good science and scientific reasoning. There are a lot of religious people out there who have no problem with evolution or the Big Bang, and there are a lot more who wouldn't have any problem with it if they really learned about it and learned how Christians like myself are still Christian while accepting all of science. Those people are people we should reach out to. Telling them that religion is idiotic, or intellectually dishonest, and that the real people who accept science must all be atheists, isn't going to help.

What's the second issue? Open source and free software. "Huh?" you may say? To be honest, I don't know the etymology of the recently-arisen term "gnu atheism", but I'd wager that it's taking the term "new atheism" (which caused all sorts of boring pedantic and semantic arguments) and riffing it together with Gnu of the Gnu project. The Gnu project is one of the original projects that pushed the notion of open source and free software, long before the term "open source" was coined. Much of that movement today would not exist without what the Gnu project had done. A lot of the core software you use on your Linux system was written under their auspices. But, more importantly, the Gnu project gave people like me, people who have a strong ethical attachment to the notion of free software, a central place to rally around. And, crucially, they provided the Gnu Public Licence, or GPL, one of the most important and most widely used free-software licenses.

Of course, there are some in the business world who see free software as a threat. So, there have been, and will continue to be, disinformation campaigns that try to link free and open source software to other dubious and/or Unamerican things, such as communism, computer crime/hackers, rampant disrespect for copyrights, etc. It's a complete misrepresentation to say that there is a conflict between "the interests of business" and free software, but that is a narrative that's out there floating about. What's more, those who tend to care about "the interests of business" are likely to be, at least in the USA, on the "right" side of the political spectrum in the common but flawed one-dimensional model of political opinion. Those who are religious and worried, or potentially worried, that the scary scientific mainstream is trying to destroy religion are also more likely to be on the right side of the spectrum.

Put it together. You have this movement out there, the subset of atheists whose stated goal is to destroy religion and who assert that complete and intellectual consistent acceptance of science requires a rejection of religion. That is a movement that people who aren't already atheists are likely to view with suspicion. Now, they've taken a name that seems to link them to something that is completely separate, open source and free software. It bugs me already for aesthetic that these guys have hijacked the term "Gnu". But it can't help but create a link in some folks' minds between this crazy hippy dubious philosophy about sharing software you've written to attacks on religion. In sort, free software may now be perceived as having something to do with yet another cultural assault that, frankly, has nothing whatsoever to do with free software. "GNU public licence? Isn't that related to those scientists who want to destroy all religion?" Sigh.

Life is hard enough for those of us who want the world to accept science, and for those of us who want the world to at least be compatible with free software. It only gets harder when some act in a way that is basically the caricature of what our opponents already claim we are.

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