The galactic spiderweb

Saturday's post was about the bizarre behavior of matter on very small scales; today's is about the equally bizarre behavior of matter on very large scales.

I was alerted to this latest discovery by two different loyal readers of Skeptophilia, who sent me a link to an article in LiveScience describing research on cosmic radio wave sources by a team led by astrophysicist Jennifer West of the University of Toronto.  The radio region of the spectrum is made up of the longest-wavelength light, and is invisible to human eyes.  In fact, the majority of the electromagnetic spectrum is invisible to us; visible light makes up only a tiny fraction of it. 

As a brief aside, I remember being kind of blown away when I first ran into this concept, back in high school.  I subsequently found out that because the refraction of light -- key to how our lenses focus the light reflected from what we're looking at onto our retinas -- is a function of wavelength, to see light in the radio region of the spectrum we'd need eyes about ten meters across.  That's assuming they functioned in an analogous fashion to our own eyes, and that the massive retinas had a light-sensitive pigment that responded to radio waves.

Which would be cumbersome, to say the least.

Anyhow, because our eyes can't see in the radio region of the spectrum, scientists have developed radio telescopes to see what's up there emitting radio waves.  And ever since we've started analyzing those invisible-to-us wavelengths, we've found surprise after surprise, starting with the 1964 discovery of the three-centimeter cosmic background radiation by Arno Penzias and Robert Wilson -- which turned out to be the relic radiation of the Big Bang.

The research by Jennifer West et al., however, has yet to be explained.  It turns out that our region of the Milky Way is surrounded by a looped array of radio-wave-emitting magnetic filaments, some of them thousands of light years long, and which connect the North Polar Spur to the Fan Region -- two segments of the night sky on opposite sides of the Earth.

At first, it wasn't even clear how far away these radio sources are.  The authors write:

Since the time of their discoveries and right up to the present day, astronomers have questioned the origin of these two regions, with some arguing that they are local features, while others argue that they are distant, Galactic-scale features...  If these features are indeed local, understanding their structure and morphology is critical since we are embedded among the stars, dust, and gas that comprise them, and all features beyond must be observed through this local veil of material.  Features that are extremely nearby can have a very large angular size on the sky, and only with good models can we account for this “contamination” when developing large-scale models of the Galactic magnetic field and foreground models for cosmology experiments.

Further study, however, clarified a couple of points; first, they're huge; second, they're kind of everywhere you look.  These cosmic filaments are strung across the Milky Way like a giant spiderweb, and some researchers believe that they're all connected -- that together they represent pieces of a single, much larger structure.

What the night sky would look like if we had enormous eyes and could see in the radio region of the spectrum

What could create something on that scale?  The simple answer is: we don't know.  These huge magnetic tubes might have been created by the explosions of massive supernovae early in the galaxy's history; one of the theories calls the structures "galactic chimneys," with matter from the explosions being funneled along the magnetic field lines of the galaxy, much as the walls of a chimney flue constrain and direct the smoke from a fireplace. "Magnetic fields don't exist in isolation," West said.  "They all must connect to each other.  So a next step is to better understand how this local magnetic field connects both to the larger-scale galactic magnetic field and also to the smaller-scale magnetic fields of our sun and Earth...  I think it's just awesome to imagine that these structures are everywhere, whenever we look up into the night sky."

Whatever they are, and however they were formed, we're currently sitting in the middle of a huge network of them -- long, hollow filaments that crisscross the sky, invisible to human eyes but clearly visible to a radio telescope tuned to the right wavelength.  

Just as in Saturday's post about the "quantum Cheshire cat," this paper raises as many questions as it settles -- certainly one of the hallmarks of cutting-edge science  And both of these discoveries further reinforce that we live in a very bizarre universe, where the familiar objects that drive our "common sense" about how things work are caught square in the middle of a world of the submicroscopic and a world of the very macroscopic, where everything we look at seems to defy our intuition.  Which you could find exciting, or disorienting and a little frightening.

Me, I think it's both.  I love that nature keeps us a little off balance, that every time we come to the smug conclusion that we've got it all figured out, we get pitched a serious curveball.  It'd be a mighty boring place if everywhere we looked, we thought, "Meh, works pretty much like I expected."

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My master's degree is in historical linguistics, with a focus on Scandinavia and Great Britain (and the interactions between them) -- so it was with great interest that I read Cat Jarman's book River Kings: A New History of Vikings from Scandinavia to the Silk Road.

Jarman, who is an archaeologist working for the University of Bristol and the Scandinavian Museum of Cultural History of the University of Oslo, is one of the world's experts on the Viking Age.  She does a great job of de-mythologizing these wide-traveling raiders, explorers, and merchants, taking them out of the caricature depictions of guys with blond braids and horned helmets into the reality of a complex, dynamic culture that impacted lands and people from Labrador to China.

River Kings is a brilliantly-written analysis of an often-misunderstood group -- beginning with the fact that "Viking" isn't an ethnic designation, but an occupation -- and tracing artifacts they left behind traveling between their homeland in Sweden, Norway, and Denmark to Iceland, the Hebrides, Normandy, the Silk Road, and Russia.  (In fact, the Rus -- the people who founded, and gave their name to, Russia -- were Scandinavian explorers who settled in what is now the Ukraine and western Russia, intermarrying with the Slavic population there and eventually forming a unique melded culture.)

If you are interested in the Vikings or in European history in general, you should put Jarman's book in your to-read list.  It goes a long way toward replacing the legendary status of these fierce, sea-going people with a historically-accurate reality that is just as fascinating.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

The cosmic whirligig

It seems like whenever I look at the realm of the very large or the very small, I quickly get overwhelmed by scale.

I remember, for example, when a teacher in high school was trying to impress upon us kids how small atoms were, and asked us the following question: if you counted up the number of atoms in a typical raindrop, then someone gave you that many grains of sand, how much sand would you have?

A bucket?  A swimming pool full?  A whole beach full?  All of those, it would seem, constitute a crapload of sand grains.  Surely there can't be more atoms in a raindrop than there are sand grains on a typical beach.

But there are.  By several orders of magnitude.  Her answer was that you'd have enough sand to fill a trench a meter deep and a kilometer across, stretching from New York to San Francisco.  (I've never checked her math, but from other similar analogies, it seems pretty spot-on.)

The same happens when I'm considering things that are very large; as much as I've studied astronomy, I never fail to be blown away simply by how enormous the universe is.  In fact, this is why the topic comes up -- a paper in Nature Astronomy last week by astrophysicists Peng Wang and Noam Liebeskind (of the University of Potsdam), Elmo Tempel (of the University of Tartu, Estonia), Xi Kang (of Zhejiang University, and Quan Guo (of Shanghai Astronomical Observatory) has demonstrated that there are filaments spanning entire galactic superclusters, and possibly longer than that.

[Image licensed under the Creative Commons The cosmic web, CC BY-SA 4.0]

The presence of these filaments, which seem to be composed largely of dark matter, comes from their effects on the galaxies they pass near.  As if they were the axle of an enormous whirligig, the filaments cause the galaxies to circle around them, drawn in by the gravitational pull.  The existence of the filaments was demonstrated by the fact that the galaxies on one side exhibit a lower than expected red shift and the ones on the other side a higher than expected red shift, meaning one side is moving away from us and the other side toward us -- just as you'd expect if the galaxies were circling some invisible center of gravity.

As with any groundbreaking discovery, it's opened up as many questions as it's answered.  "It's a major finding,” said study co-author Noam Libeskind, in an interview with Vice.  "It's a pretty big deal that we've discovered angular momentum, or vorticity, on such a huge scale.  I think it will help people understand cosmic flows and how galaxies are moving throughout the cosmic web and through the universe... [and] to understand the important scales for galaxy formation and ultimately, why everything in the universe is spinning and how spin is generated.  That is a really, really hard question to solve.  It's an unsolved question in cosmology."

That was my first reaction; what on earth (or off it, in this case) could generate that kind of angular momentum?  Think of the mass of a typical galaxy, and imaging that you tie that amount of mass at the end of a long rope and try to swing it in circles.

That's the quantity of energy we're talking about, here.  Multiplied by the number of galaxies in the universe.

But the upshot is that the universe on the largest scales seems to have an intrinsic spin, and no one knows why.  All I know is that it makes me feel very, very small.

Of course, I'm way larger than the atoms in a raindrop.  So there's that.  Now that my mind is sufficiently blown, I think I need to go huddle under my blanket for a while, because the universe is sometimes a really overwhelming place to live.

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One of the most devastating psychological diagnoses is schizophrenia.  United by the common characteristic of "loss of touch with reality," this phrase belies how horrible the various kinds of schizophrenia are, both for the sufferers and their families.  Immersed in a pseudo-reality where the voices, hallucinations, and perceptions created by their minds seem as vivid as the actual reality around them, schizophrenics live in a terrifying world where they literally can't tell their own imaginings from what they're really seeing and hearing.

The origins of schizophrenia are still poorly understood, and largely because of a lack of knowledge of its causes, treatment and prognosis are iffy at best.  But much of what we know about this horrible disorder comes from families where it seems to be common -- where, apparently, there is a genetic predisposition for the psychosis that is schizophrenia's most frightening characteristic.

One of the first studies of this kind was of the Galvin family of Colorado, who had ten children born between 1945 and 1965 of whom six eventually were diagnosed as schizophrenic.  This tragic situation is the subject of the riveting book Hidden Valley Road: Inside the Mind of an American Family, by Robert Kolker.  Kolker looks at the study done by the National Institute of Health of the Galvin family, which provided the first insight into the genetic basis of schizophrenia, but along the way gives us a touching and compassionate view of a family devastated by this mysterious disease.  It's brilliant reading, and leaves you with a greater understanding of the impact of psychiatric illness -- and hope for a future where this diagnosis has better options for treatment.

[Note: if you purchase this book from the image/link below, part of the proceeds goes to support Skeptophilia!]