The cosmic net

A fascinating new piece of research by the astrophysicists is using information from twelve billion light years away to elucidate what happened 13.8 billion years ago, at the moment of the Big Bang -- they've found the long-hypothesized "cosmic filaments," streaks of (mostly) hydrogen that extend from galaxy to galaxy and cluster to cluster.  In a paper that appeared in Science this week, titled "Gas Filaments of the Cosmic Web Located Around Active Galaxies in a Protocluster," a team led by Michele Fumagalli of Durham University found hard evidence of yet another prediction of the Big Bang Theory: that random variations ("anisotropies") in the first fraction of a second of the universe led to clumps of matter connected by streamers, with huge voids in between.

The authors write:

Cosmological simulations predict that the Universe contains a network of intergalactic gas filaments, within which galaxies form and evolve.  However, the faintness of any emission from these filaments has limited tests of this prediction.  We report the detection of rest-frame ultraviolet Lyman-α radiation from multiple filaments extending more than one megaparsec between galaxies within the SSA22 protocluster at a redshift of 3.1.  Intense star formation and supermassive black-hole activity is occurring within the galaxies embedded in these structures, which are the likely sources of the elevated ionizing radiation powering the observed Lyman-α emission.  Our observations map the gas in filamentary structures of the type thought to fuel the growth of galaxies and black holes in massive protoclusters.

So very early on, the universe was a network of thin (well, thin on a cosmic scale, anyhow) filaments of matter, and where they crossed the matter density was high enough to trigger star, and eventually galaxy, formation.

The large-scale structure of the universe.  Each of those pale blue curves is made up of millions, possibly billions, of galaxies.  [Image is in the Public Domain, courtesy of NASA]

Almost against my will I was reminded of a rather captivating image from Buddhist philosophy called "Indra's Net."  I first ran into this when I was an undergraduate, and I and some friends took a class in which we were required to read Douglas Hofstadter's mindblowing chef d'oeuvre, entitled Gödel, Escher, Bach: An Eternal Golden Braid.  This book, which combines charm, wit, music, art, and a confounding amount of high-level number theory, was a fascinating read, but there are large parts of it that -- although I was a reasonably good math student, and in fact minored in the subject -- went over my head so fast they didn't even ruffle my hair.

But the parts that I found accessible were brilliant, and he drew together a great many disciplines -- one of which was Zen Buddhism.  In that section, he described the great net that stretches across the universe as follows:

The Buddhist allegory of "Indra's Net" tells of an endless net of threads throughout the universe, the horizontal threads running through space, the vertical ones through time.  At every crossing of threads is an individual, and every individual is a crystal bead.  The great light of "Absolute Being" illuminates and penetrates every crystal bead; moreover, every crystal bead reflects not only the light from every other crystal in the net—but also every reflection of every reflection throughout the universe.

It's a cool metaphor for interconnectedness in whatever realm you like to apply it to, be it social interactions, ecological connections, the evolutionary tree of life, whatever.  But I always hesitate to bring this kind of thing up, because it's so tempting to take the metaphor as the reality -- the heart of the problem with books like Frijtof Capra's The Tao of Physics and Gary Zukav's The Dancing Wu-Li Masters, where the authors take a rather hand-waving explanation of quantum physics (about all you can do if you remove the math), draw some comparisons to Taoist and Buddhist philosophy, and forthwith conclude that the success of quantum physics as a model shows that Taoism and/or Buddhism is the real explanation for everything we see.

Confusing the model for the reality is a hazard on a lot of levels, and I had to watch that constantly when I was teaching.  I had a number of analogies I used -- the Krebs Cycle as a merry-go-round where two kids get on and two kids get off on every turn, active transport gateway proteins as revolving doors you have to pay to use, DNA as a universal recipe book.  I tried to keep the comparisons so silly that there was no way anyone would think they were real, but I still remember the student who started an essay, "So, antibodies are trash tags..."

But the comparison between the cosmic filaments crossing and generating galaxies at each intersection, and the magical Net of Indra spanning the cosmos with a reflecting jewel everywhere the threads cross, was just too pretty not to mention.  I hope it won't get in the way of your appreciation of the actual research, though, which is even more beautiful.  It's astonishing that sitting here, on this little spinning ball in the outer reaches of a quite ordinary galaxy, we've been able to learn about the structure of the universe from the very largest scales to the very smallest.  So whatever else you can say about human accomplishments, you have to admit that one is pretty impressive.

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This week's Skeptophilia book recommendation is by the team of Mark Carwardine and the brilliant author of The Hitchhiker's Guide to the Galaxy, the late Douglas Adams.  Called Last Chance to See, it's about a round-the-world trip the two took to see the last populations of some of the world's most severely endangered animals, including the Rodrigues Fruit Bat, the Mountain Gorilla, the Aye-Aye, and the Komodo Dragon.  It's fascinating, entertaining, and sad, as Adams and Carwardine take an unflinching look at the devastation being wrought on the world's ecosystems by humans.

But it should be required reading for anyone interested in ecology, the environment, and the animal kingdom. Lucid, often funny, always eye-opening, Last Chance to See will give you a lens into the plight of some of the world's rarest species -- before they're gone forever.

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