Cosmology

"We Are All Connected"

October 28, 2009

Just to ease the mental anguish inflicted by the "science of homeopathy" video, here's a fantastic musical mashup called "We Are All Connected" -- not in any vague, New Age-y way, just by the fact that we're all made of "star stuff" forged in the explosions of supernovae, as Carl Sagan so eloquently put it when Cosmos first hit the airwaves. Sagan and Cosmos are sampled, naturally, along with Bill Nye the Science Guy, astrophysicst Neil de Grasse Tyson, the History Channel's Universe series, and a set of 1983 interviews with the late Richard Feynman. Get your physics groove on!

State of the Universe(s)

October 19, 2009

Last night I had the honor of moderating a fantastic discussion between three leading cosmologists: ASU's Lawrence Krauss (of The Physics of Star Trek fame), University of Michigan's Katie Freese, and Neil Turok, now the director of the Perimeter Institute, which organized the city-wide Quantum 2 Cosmos festival. The Q2C organizers have gone all out with the multimedia: most lectures and panels are available online, streaming live while in progress, along with a Twitter feed.

We covered a lot of ground in 55 minutes, discussing the unprecedented explosion in our scientific knowledge of the universe during the 20th century and looking to the future by exploring the mysteries currently facing cosmologists: dark matter, dark energy, gravitational waves, whether inflationary theory is correct, and what might have existed before the Big Bang? These are deep waters, Watson. Okay, I had to ask Krauss about the whole "red matter" scenario in the latest Star Trek reboot (he liked the movie, had little use for the "science"). But other than that, we stuck to the serious stuff. Mostly.Dn12996-1_500

I always learn something new when I talk to scientists, and this time was no exception, thanks to Katie Freese. She told me about "dark stars": not the precursors of black holes first hypothesized back in the 1700s, but a new kind of star that may have been the first type of star to form in the early universe. Freese and a few colleagues published the seminal paper on dark stars in January 2008 in Physical Review Letters, and she's still uber-excited about the possibilities for the existence of these objects -- as well she should be.

See, if these things turn out to exist, it would significantly change current theoretical models for star formation. Right now, scientists believe the first stars formed inside clouds of dark matter, in which hydrogen and helium cooled down sufficiently to make nuclear fusion possible. The only role dark matter plays in this scenario is to supply the gravity needed for the gases to clump together in the first place.

But if Freese and her colleagues are correct, then the concentrations of dark matter particles would be so high that those particles would collide with each other and annihilate, releasing energy, and keeping the almost-star too hot to collapse down to sufficiently high density for fusion to begin. In short, it's an entirely different fuel source than that which powers "normal" stars. The next step is actually detecting them, and Freese thinks the new James Webb Telescope slated for launch in 2011 will be able to see them, although she cautions that while dark stars may shine, "they will look different than stars that operate by fusion." Emissions of gamma rays, neutrinos or antimatter could all turn out to be "signatures" of dark stars.

Like any new idea, it has its skeptics in the scientific community. Freese et al's model does rely on some necessary assumptions that may turn out to be incorrect. Most notably, their calculations are based on a type of Weakly Interacting Massive Particle (WIMP) called a neutralino -- it's the leading candidate for dark matter particles, but it may not be the right one, or the only one. But it's not an implausible scenario either. Like so much in cutting edge cosmology and astrophysics, the excitement comes from exploring what we don't know, because that inevitably leads to new discoveries.

Anyway, we ran out of time before we could really discuss dark stars in detail during the panel, but we covered lots of other great topics, and we certainly didn't ignore the "dark side of the universe." That's where all the cosmological action is these days. You can watch the whole thing below. (Note: For some reason, the "embed" feature has been giving me grief. If it's not showing up in the post, you can still watch the entire panel discussion here.)

Yeah, There's an App for That

October 15, 2009

University of Washington physicist Dave Bacon, known to the blogosphere as The Quantum Pontiff (and often dubbed "His Holiness" as a result), has a bit of a fetish for random numbers. In fact, he's even created his own iPhone App, MakeRandom, giving the user access to "custom random lists, dice random numbers and random words." It's a cute app: as Bacon describes it, you simply set up your list of choice, shake your iPhone and voila! A random result ensues!

But gosh darn it if someone hasn't gone and done the Pontiff one better: now you can download a brand new App called Universe Splitter that takes random choices into the quantum realm, specifically, Many Worlds. Every time you're faced with your very own superposition of states, you can turn to your trusty iPhone (or iTouch) for help collapsing your wave function -- or perhaps just figuring out which branch of the wave function you want to be in. To wit:Universesplitter

Scientists say that every quantum event plays out simultaneously in every possible way, with each possibility becoming real in a separate universe. You can now harness this powerful and mysterious effect right from your iPhone or iPod Touch!

How? Whenever you're faced with a choice -- for example, whether to accept a job offer or to turn it down -- just type both of these actions into Universe Splitter©, and press the button.

Universe Splitter© will immediately contact a laboratory in Geneva, Switzerland, and connect to a Quantis brand quantum device, which releases single photons into a partially-silvered mirror. Each photon will simultaneously bounce off the mirror and pass through it -- but in separate universes.

Within seconds, Universe Splitter© will receive the experiment's result and tell you which of the two universes you're in, and therefore which action to take. Think of it -- two entire universes, complete with every last planet and galaxy, and in one, a version of you who took the new job, and in the other, a version of you who didn't!

Maybe there should be an App to help you decide whether to download MakeRandom or UniverseSplitter. The former is cheaper -- $0.99 on iTunes, compared to $1.99 -- but UniverseSplitter comes with full laboratory support in Geneva, plus a testimonial by surfer-physicist Garrett Lisi. If Many Worlds turns out to be true, we all downloaded both -- we just did so in separate universes.

When the Multiverse Collides

September 28, 2009

The season premiere of The Family Guy was even edgier than usual, exploring numerous alternate universes in an episode entitled "Road to the Multiverse." Resident genius toddler Stewie invents a device that enables him to travel between parallel universes with the family dog, Brian -- who tries to pretend he knows about Many Worlds as Stewie explains the concept. It's a nice brief summary of the basic concept.

Soon Stewie and Brian are popping in and out of alternate universes: one that is far more technologically advanced than ours; one where everyone has two heads; one that is based on ironic Washington Post political cartoons; one that is completely Disneyfied, with cheery songs about pie and a touch of anti-semitism; and finally, a universe where dogs rule the world and humans are the pets. That's where Stewie meets his Dog Self and discovers he's had the device on "shuffle" all along -- hence their random jumping around. Eventually they manage to get back to their reality, bringing Alternate Pet-Brian back with them -- who [SPOILER ALERT!] is promptly hit by a bus, because after all, can two Brians co-exist in the same universe?

Scientists don't really know what would happen in such an instance. One of the critical features of most multiverse theories is that the various parallel worlds never interact. In fact, there's no direct evidence for the existence of a multiverse -- and only a few proposals for how one might detect them if they did. For instance, we might see evidence of another bubble universe if it had collided with our own a long, long time ago -- except such a collision would pretty much destroy the fabric of spacetime in both bubbles.

The latest scheme for evidence of a multiverse comes a new paper on the arXiv by Anthony Aguirre of the University of California, Santa Cruz, and Matthew Johnson, a postdoc at Caltech. They think they've come up with a version wherein spacetime in two alternative universes could be preserved, assuming they didn't so much as collide, as sideswipe -- a sort of "cosmic scrape." Signs of a such a scrape would include a negative curvature to the universe, or the remnant patterns that could be observed in the cosmic microwave background. The latter has the advantage of possibly being detected from advanced telescopes. Even then, it would be a sliver of evidence, not definitive proof.

It's still tantalizing stuff. Maybe cosmologists in a technologically advanced parallel universe will beat us to it, and detect our presence first -- inspired by their version of The Family Guy. Because if there's a mutliverse, there's got to be a version of Seth MacFarlane out there somewhere out there, too.

Brain Drain

September 10, 2009

It's rare that Sean and I argue over who gets to blog about a particular topic, but when our pal Jim Kakalios, author of The Physics of Superheroes, told us about the latest issue of The Incredible Hercules #133, oh, it was on! Because the new arch-villain(s) of the story arc are Boltzmann Brains -- or rather, "freak observers fluctuated out of thermal equilibrium." Herc_001

So who would get to blog about it first? On the one hand, science and entertainment, including comic books and other aspects of pop culture, is pretty firmly my bailiwick, given that I wrote a book called The Physics of the Buffyverse and my current job is heading up the Science and Entertainment Exchange.

On the other hand, Sean has blogged extensively about entropy, quantum fluctuations and Boltzmann Brains, and just wrote an entire book about the arrow of time in which Boltzmann figures quite prominently -- so it's clearly his bailiwick as well. In the end I caved to his greater expertise: Sean's blog post about this exciting new trend in comics is here.

What exactly are Boltzmann Brains? I'll let Sean explain, since he really is the resident expert:

The Boltzmann Brain paradox is an argument against the idea that the universe around us, with its incredibly low-entropy early conditions and consequential arrow of time, is simply a statistical fluctuation within some eternal system that spends most of its time in thermal equilibrium. You can get a universe like ours that way, but you're overwhelmingly more likely to get just a single galaxy, or a single planet, or even just a single brain -- so the statistical-fluctuation idea seems to be ruled out by experiment.

Dennis Overbye wrote a very nice overview in The New York Times back in 2008 exploring the pro and con arguments surrounding Boltzmann Brains. I'm not sure I'm quite willing to accept that I'm nothing more than a "momentary fluctuation in a field of matter and energy out in space," popping into existence just long enough to look around and say, "Hey! There's a nifty universe here!" before annihilating back into the oblivion of thermal equilibrium. But it does make for an intriguing twist on Descartes' classic maxim: "I fluctuate, therefore I am... for a split second, anyway."

Things That Make You Go "Wow!"

August 28, 2009

Janna_Levin05 In need of some cosmic head candy for your weekend? Via Phil Plait, the baddest astronomer that ever there was, here's a fantastically concise explanation of the Big Bang and the birth of our universe, with a bit of speculation about a possible multiverse as well. It's a great example of what can be done even with a budget of, well, zero.

The video  features Janna Levin, an astrophysicist at Columbia University, who really should do more of this sort of thing. She's one of the hippest theoretical physicists you're ever likely to meet: married to a jazz musician, she's lived in funky bohemian lofts with a community of artists and dabbles in painting and philosophy, in addition to teaching, raising two children, and pursuing her scientific research. All that life experience combines to give her a truly unique voice. Levin is the author of How the Universe Got Its Spots and the award-winning A Madman Dreams of Turing Machines, both quirky, genre-busting works of popular science that are well worth a read.


Finding the Fractals

August 27, 2009

Last week NOVA aired a three-part series, Hunting the Hidden Dimension, in which yours truly made a brief cameo appearance. I thought the producers did an excellent job exploring the fascinating hidden world of fractal patterns, and PBS has an excellent affiliated Website set up, wherein you can design your very own fractal.

What exactly are fractals? They arise from chaos theory. To scientists, "chaos" denotes systems that are so sensitive to initial conditions that their output appears random, obscuring their underlying internal rules of order: the stock market, rioting crowds, brain waves during an epilectic seizure, or the weather. In a chaotic system, tiny effects are amplified through repetition until the system goes critical.Famo-01-l

The mathematical offspring of chaos theory is fractal geometry. Fractals may appear haphazard at first glance, yet each one is composed of a single geometric pattern repeated thousands of times at different magnifications, like Russian dolls nested within one another. A fractal pattern is what is left behind by chaotic activity. If a hurricane is a chaotic system, then the wreckage strewn in its path is its fractal pattern.

Some fractal patterns exist only in mathematical theory, but others provide useful models for the irregular yet patterned shapes found in nature – the branchings of rivers and trees, for instance. Mathematicians tend to rank fractal dimensions on a series of scales between 0 and 3. One-dimensional fractals (such as a segmented line) typically rank between 0.1 and 0.9; two-dimensional fractals (such as a shadow cast by a cloud) between 1.1 and 1.9; and three-dimensional fractals (such as a mountain) between 2.1 and 2.9. Most natural objects, when analyzed in two dimensions, rank between 1.2 and 1.6.

There is even a chance that all the matter in our universe is arranged in a fractal pattern, at least according to a study released last year by Italian physicists. Here's what New Scientist had to say about the work:

"Nearly all physicists agree that on relatively small scales the distribution is fractal-like: hundreds of billions of stars group together to form galaxies, galaxies clump together to form clusters, and clusters amass into superclusters. The point of contention, however, is what happens at even larger scales. According to most physicists, this Russian doll-style clustering comes to an end and the universe, on large scales, becomes homogenous."

Francesco Sylas Labini and Luciano Pietronero beg to differ. Their analysis of data from the Sloan Digital Sky Survey shows that instead of the fractal pattern smoothing out at scales of over 200 million light years, if the distribution does smooth out -- and they maintain this is still an "if" -- it would have to be at scales larger than 300 million light years across.

I expect they'll be debating this for years to come. The point is, fractals are cool, so check out Hunting the Hidden Dimension this weekend if you're looking to chill, and learn more about these amazing patterns.

Image: The most famous fractal, the Mandelbrot Set.

Things That Go Bang

August 26, 2009

There's an intriguing new paper on the arXiv this week that claims to have found a mathematical link between exotic "metamaterials" and the fabric of spacetime -- specifically, how both interact with light. This is more interesting than it might seem at first glance, because whenever you have two systems that are basically identical in terms of equations, you can measure the properties of one and deduce similar properties about the other -- even if that other thing is, well, the Big Bang itself.

Take the physics of superfluid helium and the theory of general relativity, for example. Scientists often use this as an analog to map general relativity into a condensed matter system; they solve the problems in the more accessible superfluid system and then extrapolate that to general relativity. And I wrote a few weeks ago about creating analogs of black holes and event horizons.

Now a physicist at the University of Maryland named Igor Smolyaninov has found a similar analogy between general relativity and metamaterials. These are an exotic class of materials first discovered about 10 years ago that have extraordinary capabilities to bend light in new ways (eg, they can be engineered to have a negative index of refraction). Scientists at UC-Berkeley and elsewhere have been using them to create rudimentary "invisibility cloaks", among other applications.

Smolyaninov thinks it's possible to use materials to essentially recreate how light behaves in different kinds of spacetimes -- say, two dimensions of space and two dimensions of time. According to the paper, this kind of system gives rise to the "birth" of a spacetime with two dimensions of space and one dimension of time, along with a bunch of elementary particles. He describes it as "a kind of toy big bang." So in addition to creating analogs of black holes in the lab, it might one day be possible to create an optical analog of the Big Bang in the lab and thus learn a great deal about what happened to our universe when it was born.

Or we can ask someone who was actually there: Crasher Squirrel! (I know, I know, but the meme isn't officially over until Crasher Squirrel gets a cameo with Stephen Colbert, like Keyboard Cat.)
 Squirrel-crahser-was-there-for-the-birth-of-the-21187-1250692542-20

The Pros and Cons of Many Worlds

August 20, 2009

Don't you just love a good scientific debate on cutting-edge physics theories? Yeah, me too. So I was pleased when Physics and Cake linked to this terrific BloggingHeads TV diavlog between physicist/bloggers Scott Aaronson (MIT; his blog is Shtetl-Optimized) and Eliezer Yudkowsky of the Singularity Institute and the blog Less Wrong. Among the topics under discussion: the Many Worlds theory of the universe. Eliezer is pro, Scott is mostly con -- as in, he thinks the theory is ridiculous while acknowledging it might still be right. A clip giving the "Pro" side is below. Head on over toe BloggingHeads.tv for the full diavlog and/or Scott's response. Enjoy!


In Praise of Insignificance

July 14, 2009

I just got back from The Amaz!ing Meeting in Vegas, baby! For those unfamiliar with this particular conference, it's sponsored by the James Randi Educational Foundation (JREF), founded by magician, escape artist, and scourge of fake psychics and pseudoscience around the globe James Randi. My pal Phil Plait of Bad Astronomy now heads JREF, and he invited me to be a speaker at TAM this year -- an honor I was happy to accept. This was my first time at TAM, and it is, indeed, an amazing meeting: I had many fascinating, thought-provoking discussions to mull over at my leisure.

Phil did manage to put me on The Most Intimidating Panel on the Planet: it is a surreal -- and humbling -- experience to share a dais with the likes of Bill Prady (executive producer and co-creator of The Big Bang Theory), Mythbusters' Adam Savage, and the incomparable Penn and Teller. But anyone who writes about space science and cosmology is comfortable with insignificance: the greatest among us, after all, is just a tiny speck, or momentary spark, in a roiling vast cosmos that just keeps getting bigger on time scales that dwarf a human lifetime.

Check out this image: see that tiny speck of light, inside the blue circle? That's Earth, as seen from the vantage point of Saturn. We are so much smaller even than that.

530px-PaleBlueDot

Sean reminded me of this famous photo when I told him about one conversation in particular I had after the panel. One young man mentioned that, as an atheist, he always feels at a disadvantage when talking to someone who believes in an afterlife: "Our outlook is just so... bleak in comparison."

I understand where he's coming from: many people think that a world view that doesn't involve an afterlife is a depressing option: why bother trying to be a decent, moral person, the reasoning goes, if there's nothing to look forward to after death?

We were interrupted before I could fully respond to this young man -- conferences are not an ideal format for these sorts of in-depth philosophical discussions  -- but I do not think the lack of an afterlife constitutes a "bleak" outlook at all. What frightens people about their own mortality is the thought of not consciously being, and from that, perhaps, springs the human need to invent belief systems that reassure them that their death will not be the end. That, and an unwillingness to admit to ourselves just how insignificant we really are.

We are born narcissists, almost by definition, since we can only experience the world around us from our own perspective. In that sense, the world revolves around us, and no wonder the prospect of having our consciousness snuffed out unsettles us. But empirically, it's a different story. Before Copernicus, pretty much everyone in Western Europe believed that the Earth was the center of the solar system, with the sun and all the other planets orbiting it, and man, made in the image of God, ruling over the whole shebang.

There was a very good reason people balked when confronted with scientific evidence to the contrary. Accepting Copernicus meant removing man from his place at the top of the cosmological food chain. “The world had scarcely become known as round and complete in itself when it was asked to waive the tremendous privilege of being the center of the universe,” Johann Wolfgang von Goethe later wrote of the implications of a heliocentric universe to 17th century believers. “Never, perhaps, was a greater demand made on mankind.”

Until the modern era of space exploration, however, when the Hubble Space Telescope took this famous image of the Ultra Deep Field:

600px-Hubble_ultra_deep_field_high_rez_edit1

You learn to redefine vastness when you're married to a cosmologist who thinks about these things for a living. Every speck in that image is an entire galaxy. Each one of those galaxies contains billions of stars, no doubt with countless undiscovered solar systems orbiting them. Somewhere in that vast expanse, floats our tiny blue planet. We are smaller now than ever.

If one embraces an atheist worldview, it necessarily requires embracing, even celebrating, one's insignificance. It's a tall order, I know, when one is accustomed to being the center of attention. The universe existed in all its vastness before I was born, and it will exist and continue to evolve after I am gone. But knowing that doesn't make me feel bleak or hopeless: I find it strangely comforting.

Nor does it make me feel like nothing I do could possibly matter -- quite the opposite: everything we do matters a great deal. That's the great paradox. It makes our short time here on Earth incredibly precious, in which every moment should be savored. I tell my husband I love him every single day, because those days are finite. Fifty years will be gone in an instant from a cosmological perspective. Our choices, our actions, how we choose to behave toward our fellow travelers -- random kindness to strangers -- all of this becomes tremendously important when one embraces insignificance... because this life is all we have.

Photos: (top) The Pale Blue Dot (Voyager mission). (bottom) Hubble Ultra Deep Field. Source: NASA/ESA. Public Domain.

about

Jennifer Ouellette is the author of "Black Bodies and Quantum Cats: Tales from the Annals of Physics" and "The Physics of the Buffyverse", holds a black belt in jujitsu, and lives in Los Angeles with a tall cosmologist named Sean.



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