Category Archives: Science and Modern Society

Will BICEP2 Lose Some of Its Muscle?

A scientific controversy has been brewing concerning the results of BICEP2, the experiment that measured polarized microwaves coming from a patch of the sky, and whose measurement has been widely interpreted as a discovery of gravitational waves, probably from cosmic inflation. (Here’s my post about the discovery, here’s some background so you can understand it more easily. Here are some of my articles about the early universe.)  On the day of the announcement, some elements of the media hailed it as a great discovery without reminding readers of something very important: it’s provisional!

From the very beginning of the BICEP2 story, I’ve been reminding you (here and here) that it is very common for claims of great scientific discoveries to disappear after further scrutiny, and that a declaration of victory by the scientific community comes much more slowly and deliberately than it often does in the press. Every scientist knows that while science, as a collective process viewed over time, very rarely makes mistakes, individual experiments and experimenters are often wrong.  (To its credit, the New York Times article contained some cautionary statements in its prose, and also quoted scientists making cautionary statements.  Other media outlets forgot.)

Doing forefront science is extremely difficult, because it requires near-perfection. A single unfortunate mistake in a very complex experiment can create an effect that appears similar to what the experimenters were looking for, but is a fake. Scientists are all well-aware of this; we’ve all seen examples, some of which took years to diagnose. And so, as with any claim of a big discovery, you should view the BICEP2 result as provisional, until checked thoroughly by outside experts, and until confirmed by other experiments.

What could go wrong with BICEP2?  On purely logical grounds, the BICEP2 result, interpreted as evidence for cosmic inflation, could be problematic if any one of the following four things is true:

1) The experiment itself has a technical problem, and the polarized microwaves they observe actually don’t exist.

2) The polarized microwaves are real, but they aren’t coming from ancient gravitational waves; they are instead coming from dust (very small grains of material) that is distributed around the galaxy between the stars, and that can radiate polarized microwaves.

3) The polarization really is coming from the cosmic microwave background (the leftover glow from the Big Bang), but it is not coming from gravitational waves; instead it comes from some other unknown source.

4) The polarization is really coming from gravitational waves, but these waves are not due to cosmic inflation but to some other source in the early universe.

The current controversy concerns point 2. Continue reading

In Memoriam: Gerry Guralnik

For those who haven’t heard: Professor Gerry Guralnik died. Here’s the New York Times obituary, which contains a few physics imperfections (though the most serious mistake in an earlier version was corrected, thankfully), but hopefully avoids any errors about Guralnik’s life.  Here’s another press release, from Brown University.

Guralnik, with Tom Kibble and Carl Hagen, wrote one of the four 1964 papers which represent the birth of the idea of the “Higgs” field, now understood as the source of mass for the known elementary particles — an idea that was confirmed by the discovery of a type of “Higgs” particle in 2012 at the Large Hadron Collider.  (I find it sad that the obituary is sullied with a headline that contains the words “God Particle” — a term that no physicist involved in the relevant research ever used, and which was invented in the 1990s, not as science or even as religion, but for $$$… by someone who was trying to sell his book.) The other three papers — the first by Robert Brout and Francois Englert, and the second and third by Peter Higgs, were rewarded with a Nobel Prize in 2013; it was given just to Englert and Higgs, Brout having died too early, in 2011.  Though Guralnik, Hagen and Kibble won many other prizes, they were not awarded a Nobel for their work, a decision that will remain forever controversial.

But at least Guralnik lived long enough to learn, as Brout sadly did not, that his ideas were realized in nature, and to see the consequences of these ideas in real data. In the end, that’s the real prize, and one that no human can award.

Which Parts of the Big Bang Theory are Reliable, and Why?

Familiar throughout our international culture, the “Big Bang” is well-known as the theory that scientists use to describe and explain the history of the universe. But the theory is not a single conceptual unit, and there are parts that are more reliable than others.

It’s important to understand that the theory — a set of equations describing how the universe (more precisely, the observable patch of our universe, which may be a tiny fraction of the universe) changes over time, and leading to sometimes precise predictions for what should, if the theory is right, be observed by humans in the sky — actually consists of different periods, some of which are far more speculative than others.  In the more speculative early periods, we must use equations in which we have limited confidence at best; moreover, data relevant to these periods, from observations of the cosmos and from particle physics experiments, is slim to none. In more recent periods, our confidence is very, very strong.

In my “History of the Universe” article [see also my related articles on cosmic inflation, on the Hot Big Bang, and on the pre-inflation period; also a comment that the Big Bang is an expansion, not an explosion!], the following figure appears, though without the colored zones, which I’ve added for this post. The colored zones emphasize what we know, what we suspect, and what we don’t know at all.

History of the Universe, taken from my article with the same title, with added color-coded measures of how confident we can be in its accuracy.  In each colored zone, the degree of confidence and the observational/experimental source of that confidence is indicated. Three different possible starting points for the "Big Bang" are noted at the bottom; different scientists may mean different things by the term.

History of the Universe, taken from my article with the same title, with added color-coded measures of how confident we can be in our understanding. In each colored zone, the degree of confidence and the observational/experimental source of that confidence is indicated. Three different possible starting points for the “Big Bang” are noted at the bottom; note that individual scientists may mean different things by the term.

Notice that in the figure, I don’t measure time from the start of the universe.  That’s because I don’t know how or when the universe started (and in particular, the notion that it started from a singularity, or worse, an exploding “cosmic egg”, is simply an over-extrapolation to the past and a misunderstanding of what the theory actually says.) Instead I measure time from the start of the Hot Big Bang in the observable patch of the universe.  I also don’t even know precisely when the Hot Big Bang started, but the uncertainty on that initial time (relative to other events) is less than one second — so all the times I’ll mention, which are much longer than that, aren’t affected by this uncertainty.

I’ll now take you through the different confidence zones of the Big Bang, from the latest to the earliest, as indicated in the figure above.

Continue reading

Did The Universe Really Begin With a Singularity?

Did the universe begin with a singularity?  A point in space and/or a moment in time where everything in the universe was crushed together, infinitely hot and infinitely densely packed?

Doesn’t the Big Bang Theory say so?

Well, let me ask you a question. Did you begin with a singularity?

Let’s see. Some decades ago, you were smaller. And then before that, you were even smaller. At some point you could fit inside your mother’s body, and if we follow time backwards, you were even much smaller than that.

If we follow your growth curve back, it would be very natural — if we didn’t know anything about biology, cells, and human reproduction — to assume that initially you were infinitesimally small… that you were created from a single point!

But that would be wrong. The mistake is obvious — it doesn’t make sense to assume that the period of rapid growth that you went through as a tiny embryo was the simple continuation of a process that extends on and on into the past, back until you were infinitely small.  Instead, there was a point where something changed… the growth began not from a point but from a single object of definite size: a fertilized egg.

The notion that the Universe started with a Big Bang, and that this Big Bang started from a singularity — a point in space and/or a moment in time where the universe was infinitely hot and dense — is not that different, really, from assuming humans begin their lives as infinitely small eggs. It’s about over-extrapolating into the past. Continue reading

Did Hawking Say “There Are No Black Holes”?

Media absurdity has reached new levels of darkness with the announcement that Stephen Hawking has a new theory in which black holes do not exist after all.

No, he doesn’t.

[Note added: click here for my new introduction to the black hole information paradox.]

First, Hawking does not have a new theory… at least not one he’s presented. You can look at his paper here — two pages (pdf), a short commentary that he gave to experts in August 2013 and wrote up as a little document — and you can see it has no equations at all. That means it doesn’t qualify as a theory. “Theory”, in physics, means: a set of equations that can be used to make predictions for physical processes in a real or imaginary world. When we talk about Einstein’s theory of relativity, we’re talking about equations. Compare just the look and feel of Hawking’s recent note to Einstein’s 1905 paper on the theory of special relativity, or to Hawking’s most famous 1975 paper on black holes; you can easily see the difference without understanding the content of the papers.

The word “theory” does not mean “speculations” or “ideas”, which is all that is contained in this little article. Maybe that’s what theory means at a cocktail party, but it’s not what “theory” means in physics.

Second, what Hawking is addressing in this note is the precise level of blackness of a black hole… in short, whether the name “black hole” for the objects we call black holes is really appropriate. But simply the fact that black holes aren’t quite black isn’t new. In fact it was Hawking himself who became famous in 1974-1975 for pointing out that in a world with quantum physics, typical black holes cannot be precisely black — so it’s not true that nothing ever comes out of a black hole. Black holes must slowly radiate elementary particles, a process we call Hawking radiation.

From day 1, Hawking’s observation posed puzzles about how conflicting requirements of quantum theory and Einstein’s gravity would be resolved, with quantum theory demanding that all information that fell into the black hole be neither destroyed nor copied, and Einstein’s gravity insisting that there is no way that the information of what went into a black hole can ever come out again, even if the black hole evaporates and disappears. The assumption of the community has long been that the 1970s calculation that Hawking did, while largely correct, leaves out a small, subtle effect that resolves the puzzle. The question is: what is the nature of that subtle effect?

No one, including Hawking, has posed a satisfactory answer. And that is why we keep hearing about black holes again and again over the decades, most recently in the context of the “firewall paradox”. In his recent paper, Hawking, like many of his colleagues, is proposing another possible answer, though without demonstrating mathematically that his proposal is correct.

But did Hawking really say “There are no black holes”, or didn’t he??

Talk about taking things out of context!!! Here’s what Hawking actually said.

First he suggests that the edge of a black hole — called its “event horizon”, a very subtle concept when you get into the details — really isn’t so sharp once quantum effects are considered. Many people have suggested one version or another of this possibility, which would represent a small but critical correction to what Hawking said in the 1970s (and to what people understood about black holes even earlier).

And then Hawking writes…

“The absence of event horizons mean that there are no black holes – in the sense of regimes from which light can’t escape to infinity.”

Notice the final clause, which is omitted from the media reports, and is absolutely necessary to make sense of his remark. What he means is that black holes are very, very slightly (though importantly) less black than he said in his 1974 paper… because the things that fall into the black hole do in some sense eventually come back out as the black hole evaporates. I say “in some sense” because they come out thoroughly scrambled; you, for example, if you fell in, would not come back out, even though some of the elementary particles out of which you are made might eventually do so.

And then he says

“There are however apparent horizons which persist for a period of time.”

Translation: for an extremely long time, what we call a black hole will behave in just the way we have long thought it does. In particular, there is no change in any of the astrophysics of black holes that astronomers have been studying in recent decades. The only issue is what happens as a black hole begins to evaporate in a serious way, and when you look very, very carefully at the details of the Hawking radiation, which is very difficult to do.

“This suggests that black holes should be redefined as metastable bound states of the gravitational field.”

In short: In Hawking’s proposal, it’s not that the objects that you and I would call “black holes” don’t exist!  They are still there, just with a new name, doing what we’ve been taught they do except in some fine-grained detail. Not that this fine-grained detail is unimportant — it’s essential to resolving the quantum vs. gravity puzzle.  But an ordinary person watching or exploring near a black hole would notice no difference.

Notice also all of this is a proposal, made in words; he has not shown this with mathematics.

In short, although Hawking is, with many of his colleagues, working hard to resolve the puzzles that seem to make quantum theory conflict with Einstein’s theory of gravity in this context, he’s not questioning whether black holes exist in the sense that you and I would mean it. He’s addressing the technical issue of exactly how black they are, and how the information contained in the things that fall in comes back out again. And since he’s just got words, but not math, to back up his suggestions, he’s not convinced his colleagues.

Meanwhile, the media takes the five words “There Are No Black Holes” and creates almost pure fiction, fiction that has almost nothing to do with the reality of the science. Well done, media, well done. Sometimes you’re just like a black hole: information comes in, and after being completely scrambled beyond recognition, comes back out again through a mysterious process that makes no sense to anyone. Except that in your case, it’s very clear that information is lost, and misinformation is created.

Hey! That’s a new theory of black holes! (I’ll write a 2-page paper on that this afternoon…)

Polar Vortex, Climate Change, Red Herring?

Wow, it was unusually cold last week. In a small fraction of the globe. For a couple of days. And what does that cold snap, that big wiggle in the Polar Vortex that carries high-atmospheric winds around the North Pole, imply about “climate change”, also known as “global warming”, also known as “global weirding”?

The answer is very simple. Nothing.

If you heard anyone suggest otherwise — whether they said that the extreme cold implies that there is no global warming going on, or they said that the extreme cold implies that global warming is happening — you should seriously question anything that person says when it comes to climate change. Because that person does not respect (or perhaps even understand) the difference between anecdote and evidence; between weather and climate; between a large fluctuation and a small but long-term trend. Or between media hoopla and science.

In the interest of an imperfect analogy: Let me ask you this. Are you generally happier, or less happy, than you were five years ago? Answer this as best you can.

Now let me ask you another question. Did you, within the last month, have a really, really bad day, or a really, really good one?

Does the answer to the second question have much to do with the answer to the first one?

Barring an exceptional recent disaster in your personal or professional life, the fact that, say, last Thursday your car broke down, you locked yourself out of your house, your dog vomited on the carpet and you got caught in the rain without your umbrella does not have anything to do with whether you are a happier person than you were five years ago. Being a happier person has more to do with whether you have a better job, a happier family, a better sense of self-esteem, and things like that. And even if you love your job, you know there are going to be really bad days in the office sometimes. That’s just the way it goes. We all know that.

It’s the same with daily and monthly and yearly fluctuations in the stock market compared to the slow but fairly steady century-long growth of the U.S. economy (both curves corrected for inflation.)

So why, when there’s a big fluctuation in the daily, monthly or even seasonal weather, do people jump up and down about what the implications are for the long-term trends in climate? Continue reading

Happy (Chilly) New Year

Welcome 2014! And quite a start to the year, with a cold snap that rivals anything we’ve seen in two decades. I don’t remember cold like this since the horrid winter of 1994, when the Northeastern U.S. saw snowstorms and extreme cold that alternated back and forth for weeks. Of course, when I was a child in the 1970s, such chills happened a lot more often; I remember a number of New England mornings where I awoke to a thermometer reading of -20ºFahrenheit (-29ºCelsius) [244 Kelvin].

The scariest negative temperature numbers that one hears about from the media are associated with the “wind chill”, which is a number that is supposed to measure how cold the air “feels” to your skin.  But “wind chill” is a rather subjective and controversial measure — there’s no unique way to define it, since you’ll feel differently depending on how much exposed skin you have, on your body weight, on your age and conditioning, etc.  By contrast, the temperature measured by a thermometer is defined independent of how humans feel, and experts agree on what it is and means. Oh sure, people use different scales to measure it: Fahrenheit (F), Centigrade or Celsius (C), and Kelvin (K).  But the differences are no more than the distinction between meters and feet, or between kilograms and pounds; it’s straightforward, if a bit annoying, to convert from one to the other.

So everyone agrees the temperature is and feels extremely cold, But is it, from the point of nature, really that much colder than usual? To say it another way: it was 84ºF (29ºC) in southern Florida yesterday.  How much warmer is that than the -40ºF (-40ºC) that was registered in the cold Minnesota morning?

Well, you might first think: wow, it’s a difference of 124ºF (69ºC), which sounds like a huge difference.  But is it really so huge? Continue reading

The Guardian’s Level-Headed Article on Fukushima

[Note: If you missed Wednesday evening's discussion of particle physics involving me, Sean Carroll and Alan Boyle, you can listen to it here.]

I still have a lot of work to do before I can myself write intelligently about the Fukushima Daiichi nuclear plant, and the nuclear accident and cleanup that occurred there. (See here and here for a couple of previous posts about it.) But I did want to draw your attention to one of the better newspaper articles that I’ve seen written about it, by Ian Sample at the Guardian. I can’t vouch for everything that Sample says, but given what I’ve read and investigated myself, I think he finds the right balance. He’s neither scaring people unnecessarily, nor reassuring them that everything will surely be just fine and that there’s no reason to be worried about anything. From what I know and understand, the situation is more or less just as serious and worthy of concern as Sample says it is; but conversely, I don’t have any reason to think it is much worse than what he describes.

Meanwhile, just as I don’t particularly trust anything said by TEPCO, the apparently incompetent and corrupt Japanese power company that runs and is trying to clean up the Fukushima plant, I’m also continuing to see lots of scary articles — totally irresponsible — written by people who should know better but seem bent upon frightening the public. The more wild the misstatements and misleading statements, the better, it seems.

One example of this kind of fear-mongering is to be found here: http://truth-out.org/news/item/19547-fukushima-a-global-threat-that-requires-a-global-response, by Kevin Zeese and Margaret Flowers. It’s one piece of junk after the next: the strategy is to take a fact, take another unrelated fact, quote a non-expert (or quote an expert out of context), stick them all together, and wow! frightening!! But here’s the thing: An experienced and attentive reader will know, after a few paragraphs, to ignore this article. Why?

Because it never puts anything in context. “When contact with radioactive cesium occurs, which is highly unlikely, a person can experience cell damage due to radiation of the cesium particles. Due to this, effects such as nausea, vomiting, diarrhea and bleeding may occur. When the exposure lasts a long time, people may even lose consciousness. Coma or even death may then follow. How serious the effects are depends upon the resistance of individual persons and the duration of exposure and the concentration a person is exposed to, experts say.” Well, how much cesium are we talking about here? Lots or a little? Ah, they don’t tell you that. [The answer: enormous amounts. There's no chance of you getting anywhere near that amount of exposure unless you yourself go wandering around on the Fukushima grounds, and go some place you're really not supposed to go. This didn't even happened to the workers who were at the Fukushima plant when everything was at its worst in March 2011. Even if you ate a fish every week from just off Japan that had a small amount of cesium in it, this would not happen to you.]

Because it makes illogical statements. “Since the accident at Fukushima on March 11, 2011, three reactor cores have gone missing.” Really? Gone missing? Does that make sense? Well then, why is so much radioactive cooling water — which is mentioned later in the article — being stored up at the Fukushima site? Isn’t that water being used to keep those cores cool? And how could that happen if the cores were missing? [The cores melted; it's not known precisely what shape they are in or precisely how much of each is inside or outside the original containment vessel, but they're being successfully cooled by water, so it's clear roughly where they are. They're not "missing"; that's a wild over-statement.]

Because the authors quote people without being careful to explain clearly who they are. “Harvey Wasserman, who has been working on nuclear energy issues for over 40 years,…” Is Harvey Wasserman a scientist or engineer? No.  But he gets lots of press in this article (and elsewhere.) [Wikipedia says: "Harvey Franklin Wasserman (born December 31, 1945) is an American journalist, author, democracy activist, and advocate for renewable energy. He has been a strategist and organizer in the anti-nuclear movement in the United States for over 30 years." I have nothing against Mr. Wasserman and I personally support both renewable energy and the elimination of nuclear power. But as far as I know, Wasserman has no scientific training, and is not an expert on cleaning up a nuclear plant and the risks thereof... and he's an anti-nuclear activist, so you do have to worry he's going to make thing sound worse than they are. Always look up the people being quoted!]

Because the article never once provides balance or nuance: absolutely everything is awful, awful, awful. I’m sorry, but things are never that black and white, or rather, black and black. There are shades of gray in the real world, and it’s important to tease them out a little bit. There are eventualities that would be really terrible, others that would be unfortunate, still others that would merely be a little disruptive in the local area — and they’re not equally bad, nor are they equally likely. [I don't get any sense that the authors are trying to help their readers understand; they're just bashing the reader over the head with one terrifying-sounding thing after another. This kind of article just isn't credible.]

The lesson: one has to be a critical, careful reader, and read between the lines! In contrast to Sample’s article in the Guardian, the document by Zeese and Flowers is not intended to inform; it is intended to frighten, period. I urge you to avoid getting your information from sources like that one. Find reliable, sensible people — Ian Sample is in that category, I think — and stick with them. And I would ignore anything Zeese and Flowers have to say in the future; people who’d write an article like theirs have no credibility.