Quick question: what do black holes and your laptop's WiFi connection have in common? A recently honored astronomer and engineer named John O'Sullivan has the answer. There are lots of astronomy related prizes out there, but the 2009 Australian Prime Minister's Prize for Science, awarded to O'Sullivan, is noteworthy because its impact has been felt far beyond the field of astronomy and astrophysics.
See, way back in 1977, O'Sullivan co-authored a technical paper about how a set of equations known as Fourier transforms could be used to improve the optical images from telescopes that had been distorted by the atmosphere. Fourier transforms are central to modern digital signal processing: they essentially take complex wave signals and break them down into their component parts. Once the "recipe" is known, it is possible to rebuild the signal, or build a signal that effectively cancels out the noise in collected data. Fourier transforms can be applied to any wave: sound waves, water waves, and light waves.
O'Sullivan developed his techniques because he was searching for radio waves emitted by exploding black holes -- a phenomenon predicted by Stephen Hawking in 1974. O'Sullivan didn't find those objects, despite his success cleaning up the distorted inter-galactic radio waves; the remnants of those radio emissions were simply too faint. But his techniques are now central to the wireless Internet revolution, making it possible for us to surf the Web without those pesky cable hookups -- and relatively free of distortion and interference from other radio sources.
So I congratulate O'Sullivan on being so honored, and thank him not just for my wireless connection, but also for improvements to radio astronomy that have yielded images like those below of the galaxy at the center of the Perseus cluster, courtesy of the Chandra Observatory. (The first is a composite image combining optical, x-ray and radio wave imaging; the second is the isolated radio wave image.)
Via io9 and uber-fanboy Phil Plait, here's a genuine treat: actress and all-around Web goddess Felicia Day (Dr. Horrible's Sing-Along-Blog, The Guild) shows off her science chops in a new PSA from the Spitzer Science Center on behalf of the Spitzer Space Telescope. Apparently there was a bit of public consternation earlier this year when the folks at Spitzer announced the "imminent" collision of two distant galaxies.
Our intrepid heroine battles condescension and sarcasm from a highly misguided director -- not to mention awkward cameo voice-overs from Sean Astin -- to reveal the far less scary truth about what really happens when galaxies collide. "Once again, Felicia Day sucks all the fun out of our film," the director snipes; she clearly finds truth to be a buzzkill.
But wait! Maybe it's not entirely the director's fault! Consider the slightly sensational tenor of the opening paragraphs of the press release the Spitzer folks issued back in March:
A new image from NASA's Spitzer Space Telescope offers a rare view of an imminent collision between the cores of two merging galaxies, each powered by a black hole with millions of times the mass of the sun. The galactic cores are in a single, tangled galaxy called NGC 6240, located 400-million light years away in the constellation Ophiuchus. Millions of years ago, each core was the dense center of its own galaxy before the two galaxies collided and ripped each other apart. Now, these cores are approaching each other at tremendous speeds and preparing for the final cataclysmic collision. They will crash into each other in a few million years, a relatively short period on a galactic timescale. [emphasis mine]
No wonder the Spitzer Science Center found they needed a PSA to correct public misconceptions. The universe is an awe-inspiring place, and I'm all for punching up the prose stylings a bit when communicating science broadly. But if you describe colliding galaxies as "cataclysmic," don't be surprised if there are a few directors out there who get the wrong idea. As Felicia herself points out (in the name of Joss Whedon), real science is pretty darn cool all on its own. You don't need to punch up the verbiage quite that much.
There's nothing quite like taking science to the people in the form of their local pub, particularly if it's part of the ongoing Quantum to Cosmos Festival, hosted by the Perimeter Institute in Waterloo, Canada. Last night I joined physicists Lee Smolin (a founding member of Perimeter, Jazz Whisperer, and author of The Trouble of Physics, among other books) and Cliff Burgess (McMaster University and All-Around Mensch) to chat with our fellow imbibers about the Large Hadron Collider, the Standard Model of particle physics, what one might do with an old, outdated accelerator, and after the alcohol took effect, we even delved a bit into quantum gravity (Lee's bailiwick). Good times!
The festivities were hosted by ringmaster Wilson da Silva, Awesome Dude -- also editor ofCosmos magazine. Those Aussies know how to bring science where it counts. There are photographs of the event, oh yes, and there was supposed to be a podcast suitable for downloading, but apparently we didn't speak loudly enough and there were "technical issues" as a result. No matter. A good time was had by all, especially the panelists.
The evening's title was "The Biggest Gamble in Physics?" because Wilson believes in bringing the controversy right out of the gate. The Large Hadron Collider is a huge machine, very powerful, very expensive -- is it worth the price tag for whatever we're likely to discover (if anything)? Cliff quickly established himself as the optimist among us, convinced we will not only find the Higgs boson when the LHC (finally) turns on, but a few other exciting things too. He's expecting surprises, and looking forward to them.
I conceded that it might be difficult for the average Person on the Street to justify spending that kind of money on a big machine to explore the Big Bang when people are losing their jobs and homes in droves (especially in the US), but pointed out that there are economic benefits as well: the LHC generates jobs and spinoff technologies, many of which we can't even envision yet. And Lee brought some much-needed perspective by quoting Eric Weinstein: "For the cost of bailing out one bank, we put a man on the moon." (And that's not counting all the hefty bonuses announced this past week.)
We also commiserated about the difficulty in summing up the Standard Model of particle physics for a general audience. Wilson claims he once tried to write a short sidebar summary for a Cosmos feature, "and 748 words later, I was finally finished." I marvel he could do so in under 1000 words. I like to use the analogy of a big noisy family of particles, akin to the loud Greek relatives in the film My Big Fat Greek Wedding: there are all kinds of cousins, second cousins, aunts and uncles, half of whom are named Nick, and even the occasional crazy grandparent making a rare appearance. It's tough to keep them all straight. So with the Standard Model. Lee says his goal is to reduce the model down to something more manageable, along the lines of Goldilocks and the Three Bears. It would be easier to just have a Papa Bear, Mama Bear and Baby Bear.
That complexity, of course, is why it proved so difficult to dispel the myth that the LHC will create a big black hole that will destroy the world. No major media outlet could resist the temptation to play the Doomsday card, although the Daily Show gets kudos for ridiculing the mastermind behind the hysteria. I argued that, as annoying as the media coverage became, the LHC was the third biggest news story of 2008. The LHC has fantastic name recognition, even if it's as a Doomsday Machine.
Afterwards, we repaired to Perimeter's famed Black Hole Bistro -- it seemed fitting, if the LHC is going to make a black hole to destroy the world -- where we hobnobbed with fellow panelists, and I got to hover shyly near author Neal Stephenson (Anathem, The Baroque Cycle, and my favorite, Snow Crash) as he chatted with MIT's Neil Gershenfeld and others. Even I have my Fangrrl moments. All in all, it was an amazing festival experience, and I'm sorry I could only take in such a small part of it.
Could there be a potential black hole lurking in your bathtub? I guess it depends on how you define black hole, but over the past few years there have been numerous stories in the science press about researchers creating "analogs" to black holes in their labs. After all, to a cosmologist, a singularity might lie at the center of a black hole, and represent a point of infinite density, but mathematically, this just means that the equation blows up to infinity. In that sense, the singularity may be nearer than we think.
Physicist Michael Berry (University of Bristol in England) has been saying for decades that
not all singularities are evil. He frequently writes about the
mathematical equivalent of such singularities in light, showing up in
rainbows, at the bottom of swimming pools, even in teacups. And Bill Unruh, a physicist at the University of British Columbia, proposed the notion of creating analog black holes way back in 1981.
Back then, Unruh talked about so-called "dumb holes," thus named because instead of light not being able to escape, sound waves were trapped: this is a black hole that can't speak not a black hole that can't shine. It turns out that rotating black holes exhibit a pattern of wave amplification that is also found in the surface waves of water swirling down a bathtub drain.
The same equations describe both phenomena. Per this article in Physics World:
"[Unruh] imagined fish trying to swim upstream away from a waterfall, which represents a black hole. Beyond a certain point close to the waterfall, the current becomes so strong -- like an event horizon -- that fish cannot swim fast enough to escape."
Replace "fish" with "sound", and you get the basic idea.
Both Berry and Unruh were essentially engaging in thought experiments, but their experimental colleagues have caught up with them. Fast forward to 2008, and we have Ulf Leonhardt and his cronies at the University of St. Andrews in Scotland touting their creation of a black hole analog from a length of optical fiber and laser light -- similar to what Berry has described. It's so much easier to study a black hole analog in a tabletop experiment than the enormous real-world counterparts lurking mysteriously at the centers of galaxies. (Earlier, his team had also worked with creating black hole analogs in moving fluids, akin to the fish analogy cited above.)
And in June came news that physicists at The Technion in Israel had successfully created Unruh's "dumb hole" in the lab -- a sonic black hole from which any sound that crosses its "event horizon" cannot escape. They used a Bose-Einstein condensate (BEC) -- two clouds of atoms cooled to just a few degrees above absolute zero -- to create a "well" into which air flows faster than the speed of sound. Sound "falling" into the well can't keep up with this fast-moving air, and thus cannot escape.
Sean Carroll (a.k.a., my Spousal Unit) at Cosmic Variance has an excellent post explaining what this all means when you bring in quantum mechanics and start thinking about analogs for, say, Hawking radiation and quantum gravity. But I just think it's a cool notion that we can simulate black holes in the lab -- or in our bathtubs.
Black Hole Week is still going strong here at Twisted Physics. There's no end to surprising facts about these enigmatic objects. One of my favorite black hole discoveries of the last few years was the 2003 detection of a "singing black hole" at the center of a galaxy in the Perseus Cluster, some 250 million light years from Earth. It's not actually trilling its way through a famous operatic aria like "Nessun Dorma" -- Luciano Pavarotti's reputation is secure -- and it only sings one note: B flat. But it is the lowest possible B flat ever detected.
The Cambridge University scientists used the middle C note on a piano keyboard as a reference point when determining where the droning note emitted by the black hole would fall on the musical scale. On a keyboard, the B Flat nearest middle C is 1-1/2 steps away.
The black hole's B Flat, however, is a whopping 57 octaves below middle C -- one million, billion times lower than what the human ear can detect. That gives the sound waves a frequency of 10 million years, compared to 1/20th of a second.
They are the result of the sound waves, transmitted through the bits of dust and gas that make up the interstellar medium. Chandra saw lots of concentric ripples in the interstellar medium -- ripples the size of 30,000 light years. The actual ripples are caused by gravitational effects from all those galaxies clumped together in the Perseus Cluster. The black hole pulls matter in, but in the process jets of material shoot out around it, creating pressure waves. And to scientists, pressure waves are just sound waves. Anyway, it was this X-ray radiation that NASA's Chandra X-Ray
Observatory detected in 2003, providing indirect evidence of a
"singing" black hole.
Because they carry acoustical energy, those sound waves keep the gas dispersed throughout the cluster warmer than it would otherwise be. It's not just a bizarre acoustical curiosity, either: those warmer temperatures regulate the rate at which new stars form, so the sound waves could prove to be critical to our understanding of how the universe's structure evolves.
Our musical black hole in the Perseus cluster might be a one-note wonder, but Pavarotti never promised to unlock the secrets of galaxy formation. We're just sayin'....
Image: Sound waves from a black hole in the Perseus Cluster. Source: NASA/Chandra.
Some 10 billion light years away is a mysterious "X ray source" that dates back to a mere 3 billion years after the Big Bang -- right when lots of galaxies and blacks were forming. It seems to be a kind of "cosmic ghost" lurking around a distant black hole, according to scientists with NASA's Chandra X-Ray Observatory mission. We're not talking "ghost" as in that 1990s Patrick Swayze movie; this is lingering evidence of a huge eruption from a black hole.
That's what Cambridge University's Andy Fabian thinks, anyway. "We'd seen this fuzzy object a few years ago but didn't realize until now that we were seeing a ghost," he says. "It's not out there to haunt us, rather it's telling us something -- in this case, what was happening in this galaxy billions of years ago."
Sounds kind of like an "actual" (and I use that term loosely) ghost to me -- they're always trying to solve their own murders or reveal secrets of the past. In this case, the "ghost" is the X-ray remnant "afterglow" of a power explosion from the central black hole -- so big, it would have been the equivalent of a billion supernovae. That is one violent event.
This kind of outburst produces a huge amount of radio and X-ray radiation that usually dies down after a few million years. So why are we seeing this ghostly X-ray remnant? Fabian explains that the cosmic microwave background is to blame -- another glowing artifact, this time from the actual Big Bang. Less energetic electrons can still produce x-rays, it seems, because they keep colliding with photons in the CMB. This gives them a boost of extra energy so they emit faintly in the X-ray regime of the spectrum. The result is a lingering X-ray source that can last as long as 30 million years after the initial radiation has died away.
That's not all: HDF 130 might not be the only object being haunted. Fabian and his co-author, Caitlin Case, figure that the night sky is actually filled with these sorts of "ghosts"; black holes apparently erupt more often than you might think. So long as they're the "good" kind of "ghost" that helps us solve the mysteries of our early universe, that's probably okay.
Image: HDF 130 as seen in the Chandra Deep Field North, one of the deepest X-ray images ever taken. NASA/Chandra X-Ray Observatory
Welcome to Black Hole Week at Twisted Physics: Part Deux. We think of black holes as a 20th century invention, dating back to 1916, when Einstein published his theory of general relativity and fellow physicist Karl Schwarzschild used those equations to envision spherical section of spacetime so badly warped around a concentrated mass that it is invisible to the outside world. But the true "father" of the black hole concept was a humble 18th century English rector named John Michell -- a man so far ahead of his scientific contemporaries that his ideas languished in obscurity, until they were re-invented more than a century later.
Born in 1724, Michell attended Cambridge University and wound up teaching there for a time, before becoming rector of Thornhill, near the town of Leeds. He is described somewhat unflatteringly in contemporary accounts as "a little short man, of black complexion, and fat," who was nonetheless "esteemed a very ingenious Man, and an excellent Philosopher." For a small-town rector, he had some pretty impressive scientific connections: Benjamin Franklin, Joseph Priestley and Henry Cavendish all visited him at some point in his career.
Michell's research interests were all over the map. He started out looking into magnetism, then made a few waves after the big Lisbon earthquake of 1755, proposing that earthquakes propagate as waves through solid earth -- thereby helping establish the field of seismology.
He conceived and designed the experimental apparatus later used by Cavendish to measure the force of gravity between masses in the laboratory to get the first accurate value for the gravitational constant ("G"). And he was the first to apply statistical methods to astronomy, studying how stars were distributed in the night sky and arguing that there were far more "pairs" or groups or stars than would happen with random alignments. His analysis provided the first evidence for binary stars, and star clusters.
But it was a paper Michell wrote in 1783 that proved the most revolutionary. He didn't set out to "invent" black holes; he was just casting about for a handy method to figure out the mass of a star.
This was before scientists knew that light was both particle and wave, and Michell sided with the pro-particle Newton. And since light was made of particles, he figured that when they were emitted by a star, that star's gravitational pull would reduce their speed -- much like what happens when you toss an apple into the air. He thought he could measure how much the speed of light was reduced and from that, calculate the mass of a star.
It was a sensible enough scheme: Ole Roemer had measured the speed of light the century before, so Michell had a ballpark figure with which to work. He also understood the concept of "escape velocity" -- namely, any light particle must move faster than a certain critical speed in order to escape from a star's gravitational pull. And that critical speed would be determined by the mass and size of the star.
Here's where Michell found himself pondering an intriguing "what if?" scenario: what would happen if a star was so massive, and its gravity so strong, that the escape velocity was greater than the speed of light? Well, what happens when you throw an apple into the air without sufficient velocity to escape the Earth's gravity? It falls back down to Earth. Michell figured the same thing would happen to particles of light emitted by a super-massive star more than 500 times the mass of the sun: it would fall back to the surface, rendering that star invisible to astronomers.
Michell even thought it might be possible to indirectly detect such "dark stars" if they had a luminou "twin" circling them -- a binary star system -- making him doubly prescient. It's one of several different methods modern astronomers use to infer the existence of black holes.
Today we define black holes as volumes of space in which gravity is so strong, not even light can escape. It might be said that John Michell, that short, fat rector, was born under a dark star. He never achieved sufficient escape velocity for his ideas to break out of Thornhill. He died in quiet obscurity, and his notion of a "dark star" -- that Newtonian precursor to our modern notion of a black hole -- was forgotten until his writings re-surfaced in he 1970s. Consider it a form of conceptual Hawking radiation: eventually, his ideas found their way into the light.
Image: Title and excerpt from Michell's 1783 paper in which he first described the concept of a "dark star." Source: Philosophical Transactions of the Royal Society of London, Vol. 74, p.35, 1783.
It's Black Hole week here at Twisted Physics, primarily because my fodder file is choked to the brim with various collected items related to these gravitational bad boys of physics. How bad are they? Michael Jackson "Beat It" bad. In fact, a couple of months ago, scientists at the Harvard-Smithsonian Center for Astrophysics warned of rogue black holes rum amok in the Milky Way, ready to gobble up any random bits of matter that stumble into their path, just like the army of zombies in "Thriller."
Fortunately, our pretty blue planet doesn't hang out in those sorts of neighborhoods -- ours is more of a gated community type of planet, where the neighbors keep the lawns well-tended and everyone's kids attend private school. The closest rogue black hole should be several thousand light years away. And it's just a theoretical prediction right now. So these objects are mostly of interest to astrophysicists who like to walk on the wild side of their research now and then. Rogue black holes are remnants from the days when the early universe was just starting to form galaxies, like our Milky Way, so studying them could provide clues to the mechanisms underlying galaxy formation.
HSCfA's Ryan O'Leary and Avi Loeb say that rogue black holes probably started out with some small-time, juvie stuff: individual black holes lurking at the centers of tiny galaxies with very little mass, waiting for trouble to find them. Turf wars were almost inevitable in the roiling days of the early universe: these tiny galaxies would occasionally collide (rumble!), and every time this happened, the black holes at the center of each would join forces and merge to form a gang single "relic" black hole.
Where might we find these rogue black holes today? Probably in the outer reaches of the Milky Way. That's because when two black holes merges, they would emit a powerful kick of gravitational radiation and recoil in response. It would be strong enough to propel the new relic black hole to the outer edge of the galaxy, but not strong enough to leave the state completely. They should still be lurking there: hundreds of them, each with a mass ranging from 1000 to 1000,000 times the mass of our sun.
Not that we'd be able to see them. They're more like rogue ninjas in that respect, only visible in the act of consuming -- or, as astrophysicists call it, "accreting" -- matter. But Loeb and O'Leary think that there might be another telltale sign of a rogue black hole's existence: highly compact star clusters. Apparently rogue black holes travel with a posse of hangers-on. When the black hole recoils out of the dwarf galaxy, it takes a small retinue of stars with it, just those nearest to the Great Gobbler.
Such a cluster would be small enough, and dense enough, that it might look to us like a single star. Astronomers would need to study the spectrum of stars in existing sky surveys carefully to determine if there were one, or multiple stars. Either way, "The surrounding star cluster acts much like a lighthouse that pinpoints a dangerous reef," says O'Leary. We can find a rogue black hole by the dense company it keeps.
Image: David Aguilar, Harvard-Smithsonian Center for Astrophysics.
Terminator: Salvation, the fourth film in the hugely successful franchise, opened pretty strong a few weeks ago at the box office, but faced some criticism for abandoning the time travel underpinnings of its earlier installments, and focusing instead on a futuristic war with the machines. If you look at the progression of themes in the franchise, however, it's clear this was a natural choice for the filmmakers to follow.
In the original, of course, Ah-nold is the bad guy, a robot killing machine machine who travels back in time to take out the mother of the future leader of the resistance -- before she has a chance to meet the father of her child. The robot fails; the future is secure. Terminator 2, easily one of the best sequels in cinematic history, took the point one step further, with a toughened-up Sarah Connor trying to stop Armageddon and making this her mantra: "No fate but what we make." That is, the future isn't written in stone; if we can change the course of events. And she succeeds -- temporarily.
In Terminator 3, we get another interesting twist. Despite all these attempts to rewrite history, the apocalypse still happens in the end -- just not in quite the same way it was supposed to happen. The implication? The future is inevitable, no matter how much one tries to change it. So the focus in T4 shifts to that inevitable future, choosing instead to ruminate on a new question: what makes us human.
Certain physicists like to nerd-gas about violations of physics in time travel movies. My own spouse, Sean, recently posted some helpful "Rules for Time Travelers" over at Cosmic Variance, outlining his pet peeves about how the topic is often portrayed in film. Three in particular are worth singling out because they relate to characters wanting to travel back in time in order to change the past.
The problem with this, as Sean points out, is that "If something happened, it happened." Based on everything we know thus far about relativity, quantum mechanics, and the like, even if one could travel backwards in time -- and this is a very difficult feat to accomplish -- it would not be possible to change the past, because the past already happened. For much the same reason, you can't travel back in time to a point where your spiffy time machine hasn't been invented yet. This is known in hip physics circles as the "chronology protection conjecture."
But then Sean comes through for sci-fi fans and includes a loophole: you can't change the past unless you go to a parallel universe. I've written about the "Many Worlds" theory before, and these days the notion of a multiverse is no longer grounds for automatic dismissal as a crackpot by the physics community.
Here's the gist: If you travel to a parallel universe, you can change your past, or at least experience a different outcome, because what you're actually doing is traveling to a different branch of the wavefunction. It's not really "your" past; you can only experience one branch of reality at a time. But things may have turned out differently for you in a parallel universe. And thus launched a thousand new sci-fi subplots.
That's certainly the approach taken on Fringe during its season finale: [SPOILER ALERT!] Olivia starts dimension-hopping as a result of all that messing with her brain and taking some sort of weird (and totally fictional) mind-control drug called cortexifan as a kid. So she's shunting back and forth between her reality and an alternate Earth where Boston is a bombed-out ruin and the inhabitants are preparing to go to war with the "other" Earth. Or something. Also? Main character Olivia's phone is black in one dimension, red in the other, and her co-worker's desk has been moved. ZOMG! Alert the media! As io9 snarkily concludes, "So things are more dangerous and stylish in Parallel Earth."
Who knows what those crazy kids behind the wackiness that is Fringe will come up with next? Now that they've found a semi-plausible means of side-stepping the chronology protection conjecture, Olivia is free to make her own fate -- or rather, to choose the branch of the wavefunction with the best outcome, from her perspective. I hope it's one where Walter Bishop remains his zany, brilliantly wacky self, since an alternative in which he's a buttoned-down, respectable member of the scientific establishment would be too, too dreary....
For the first time in many, many years, I was unable to attend the annual April Meeting of the American Physical Society, held this past weekend in Denver -- technically in May, but who's quibbling? So I missed out on some of the latest news in astrophysics, cosmology, high energy physics, nuclear/particle physics, and so forth -- including a round-up of talks covering the first data results collected from the Fermi Gamma-ray Space Telescope (a.k.a., "The Telescope Formerly Known as GLAST") launched last June to great fanfare. It's been merrily orbiting away ever since, some 350 miles above Earth, surveying the entire sky every three hours or so.
The Fermi Telescope is specifically looking for gamma ray bursts, mysterious yet spectacular displays that release more energy in just a few seconds than our Sun will emit over 10 billion years. In fact, Charles Meegan of USRA -- one of the physicists speaking at the APS meeting -- reported the detection of a GRB with more energy than roughly 9000 supernovae. GRBs are so bright astronomers can detect GRBs that are billions of light years away. Scientists think these bursts are caused by the collapse of massive stars, and the hope is that by studying the light from GRBs, we can learn much more about the first generation of stars at the birth of the universe.
The most violent displays are called blazars: distant galaxies that emit highly variable amounts of energy originating from supermassive black holes at their centers. Like many active galaxies, a blazar emits jets of particles and light as clouds of dust, gas and sometimes even an errant star fall into those supermassive black holes. In the case of blazars, the galaxy is oriented in such a way that we're looking right down the jet -- staring down the barrel of a gun, as it were, that fires high-energy gamma-ray bursts.
The Fermi Telescope has already discovered more blazars in its first nine months of operation than the instrument aboard NASA's aging Compton Gamma Ray Observatory has detected in 10 years, according to James Chiang of the SLAC National Accelerator Laboratory/Kavli Institute for Particle Astrophysics and Cosmology. One such blazar is PKS 2155-304, located 1.5 billion light-years away in the southern constellation of Piscis Austrinus. Normally it's fairly faint gamma-ray source, but in 2006 it got a bit frisky, producing a major burst of energy and briefly becoming the brightest detectable source in the sky.
Personally, my favorite outcome of the Fermi Telescope's first nine months is the movie NASA debuted in April -- an animation showing gamma rays from sources all across the visible universe as blazars fade in and out, so that the sky resembles a bubbly froth. The movie, made from the first 87 days of data, shows the entire sky as northern and southern halves, with the plane of the Milky Way running along the circular edges. Add it to the growing collection of "space porn": nifty animations of space science, like this one, deftly explaining the mission of the Fermi Telescope when it was still going by the moniker GLAST:
Photo: Artist's conception of a blazar emitting a gamma ray burst pointed toward Earth. Source: NASA Goddard Space Center.
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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