Quantum Quest, an animated adventure

October 29, 2009 | 6:53 am

On Wednesday October 20, 2009, the Imagine Science Film Festival hosted the world premier of Quantum Quest: A Cassini Space Odyssey, an animated tale about a photon named Dave, who lives in the sun and is sent on a quest to save the telescope Cassini. Quantum Quest has all the ingredients for a good kids movie: funny and lovable characters throughout, a battle of good and evil, and a take-home message about believing in yourself. But more than anything, the film boasts quite possibly the most up-to-date and astounding animations of the solar system available. Astronomy lovers will weep.

Dave is a photon living in the core of the sun and mostly living a safe, normal life. He and the other photons look like humans, except that they’re glowing yellow and have odd body tattoos and tails down to their feet. And, of course, they talk. Living in the sun with the photons are neutrinos (also human-shaped but green, and with Tweety-bird-like heads) and protons (upright-walking lizards). Dave’s world is shaken up when he is given the task of carrying a vital message to Cassini in order to prevent its destruction by the armies of The Void and his right-hand man Captain Fear. His minions of dark matter threaten to gobble up anything living or light, and they hate knowledge–hence their desire to destroy Cassini.

While the film is cute, it’s no Pixar triumph, and packs the plot into very few words and very little time. Still, its characters got to me and I laughed at the jokes. Plus, it did a neat job of working some real science into a story of this kind (for example, the neutrino Reina can escape from the enemy because none of the fundamental forces affect her much). It did boast an unbelievable cast, which included two Captain Kirks (William Shatner and Chris Pine) and two Darth Vaders (James Earl Jones and Hayden Christensen).  It also included Jason Alexander, Sandra Oh, Abigail Breslin, Amanda Peet, Mark Hamill, Samuel L. Jackson, and others. Oh yeah, and Neil Armstrong.

But the film’s greatest achievement isn’t its story line or the acting–it’s the animations of the solar system that will captivate audiences both young and old. The film will have a major release in IMAX theaters in February 2010, where it will be shown in 3D (the admittedly unfinished draft we saw was only in 2D). Quantum Quest will probably appear mostly in science museums, and it represents a leap forward in movies of this kind. The imagery of the inner planets, the rings of Saturn, and the Kuiper belt near the edge of the solar system are stunning, and extremely accurate. Based on information from a variety of NASA missions, the film actually identifies on screen which mission provided information about which solar system body. Where was this movie when I was 12? I can easily see this production giving a big boost to kids’ curiosities about space.

At a panel discussion after the film, the writer and co-director Harry Kloor discussed how he got into science through science fiction. Kloor holds PhDs in both physics and chemistry, but has also written for Star Trek: Voyager. Someone asked how he decided when to use very accurate science in the film, and when to use science fiction; the audience member gave the example that Dave the photon and Reina the neutrino could hear each other talk in space. Kloor reminded the viewer that it was a leap to have the photon and neutrino talk at all, and in cases where the story was clearly fictionalized they didn’t worry about scientific details. But, he says, whenever science is presented as science, it’s totally accurate. Kloor said kids seem to know where the science and the science fiction split–it’s adults who can’t seem to separate them.  And perhaps Kloor is onto something in terms of combining science and fiction, by making it very clear when the film is discussing science and when it isn’t.

While I couldn’t quite figure out why (and was too happy to care) Kloor brought with him to the panel discussion four-time space shuttle astronaut Dan Barry. Barry has logged over 700 hours in space, with 25 hours in space walks working on the international space station. Over six feet tall and thin as a rail, Barry was a giant on the stage next to Kloor as they discussed science and entertainment. Barry discussed how he got into science through his desire to fly (“I was the kind of kid who jumped off everything…”), which eventually led him to a career as an engineer. In the Q&A, an audience member asked Berry about his experience in space, at which point he recounted, with awe and grace, the first time he looking down at the Earth on a space walk. He had made sure NASA bought him a new visor so he could see the whole thing clearly. His description of the colors, shapes, and gradients of the earth, compared to the pure blackness of space, had the whole audience silent. “You just can’t capture it with a camera,” he said. “You really have to go see it yourself.”

Quantum Quest is planned for wide release in February 2010.

Calla Cofield

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Gamma-ray burst restricts ways to beat Einstein’s relativity

October 28, 2009 | 1:00 pm

In this illustration, one photon (purple) carries a million times the energy of another (yellow). Some theorists predict travel delays for higher-energy photons, which interact more strongly with the proposed frothy nature of space-time. Yet Fermi data on two photons from a gamma-ray burst fail to show this effect, eliminating some approaches to a new theory of gravity. Click for an animation that shows the delay scientists had expected to observe. Credit: NASA/Sonoma State University/Aurore Simonnet

Sometimes a single photon can tell us a lot. Especially when it comes barreling toward us with extremely high energy from a gamma-ray burst billions of light-years away. If you catch just the right photon in just the right way, it might even tell you something about the fundamental structure of space-time and provide guidance toward unifying gravity and quantum physics.

In a paper first published on the arXiv on August 13, and then published in Nature today, the Fermi Gamma-ray Space Telescope team presents a reconstruction of the gamma-ray burst GRB090510, observed on May 10, 2009. The burst included a 31 GeV photon, one of the highest-energy photons ever observed from a gamma-ray burst. Although no grand sweeping statements can be made, this observation does place some limits on the kinds of theories physicists can develop about the nature of space-time.

This burst and photon have already received a lot of attention over the past few months and will get a lot more in the coming days, probably with a series of arguments and claims about how this kills or doesn’t kill various theories of quantum gravity. Based on what has already happened on the Web, the discussion is likely to become pretty rancorous with a small re-inflammation of the string wars on the way. But behind all the shouting, there is a lot of interesting science going on here and the real potential to increase understanding of astrophysics and provide some guidance for the future of quantum gravity theories.

What quantum gravity says about space-time

To set the scene, we need to know a little about quantum gravity. At this time, there is no complete theory of quantum gravity, but there are various frameworks for trying to understand the problem. String theory and loop quantum gravity are probably the best known of these, but there are many other attempts to build quantum physics and gravity into one theory.

Without going into details of specific frameworks, many quantum gravity frameworks adopt the idea that space-time itself might be quantized, or made up of some kind of fundamental unit or grainy structure, down on the level of billionths of billionths of the size of an atom’s nucleus. If that is indeed the case, there are many reasons to think that light moving through that quantized space-time might “feel” the quanta as it travels. One consequence could be that light of different energies would travel at different speeds.

The biggest problem is that no frameworks of quantum gravity really make concrete predictions of anything much. Instead, much of this research is phenomenology, a realm that sits somewhere in between fundamental theory and experimental observation. Phenomenological theories are designed to match experimental observation, and are often inspired by ideas from fundamental theory, but generally can’t be derived purely from fundamentals.

For example, some quantum gravity frameworks suggest that space-time is quantized. This could show up as the speed of light depending on the energy of the photons. But if it does, then the speed of light should vary with energy in some generic way that can described by an equation. In particular, it seems reasonable that the speed of light should be modified by a small correction that depends on the ratio of the energy of the light to some other energy scale. Quantum gravity frameworks suggest that the appropriate energy scale is called the Planck energy. And because energy scales and distance scales are related in these frameworks, that energy corresponds to a length called the Planck length, which is about the scale on which space starts to look like it is made up of little chunks rather than a continuum. The Planck length is about 10^-35 meters—a proton is about 100 billion billion times larger in diameter.

That equation that relates speed of light to energy can’t yet be deduced strictly from the fundamental quantum gravity ideas but these phenomenological equations should have the right structure and properties. Importantly, the equation can be tested against observation. If scientists could observe light of different energies traveling over long distances, they might be able to notice any differences in speed and see if the equation matches.

If that phenomenological equation does matches observation, it gives theorists a hint that their underlying theories could be on the right track and that the details should predict the kind of universe that equation describes. If not, then theorists had better look elsewhere.

Light from gamma-ray bursts

Physicists realized a decade or so ago that if light of different energies travels at different speeds, then the current generation of gamma-ray space telescopes might be able to observe those effects. What would be needed is to observe light coming from a compact source in a short burst a long way from us. By being compact and from a short burst, physicists could be confident that the light is all starting from the same place at the same time. By being a long way off, the light has enough of a chance to separate out, with the highest energy light being delayed slightly relative to the lower energy light. It might seem strange that it is the highest-energy light that is delayed, but a hand-waving argument for this is that the highest energy photons are more likely to interact with the graininess of space-time and so feel its effects more and are slowed most.

GRB090510 is precisely the kind of burst that physicists were hoping for to make this kind of measurement and test, and the Fermi telescope managed to collect good clean data to analyze.

Of course, nothing in astrophysics is as simple as it might sound, and the situation here is quite messy. For starters, nobody knows precisely what happens in a gamma-ray burst. Without knowing the mechanism of the burst, they can’t pin down precisely where and when the gamma-ray photons come from. That means physicists can’t just compare the arrival times as they depend on energy and calculate a speed. Instead, physicists can place some limits on how much quantum gravity effects could influence the speed working under a set of assumptions about the astrophysics involved. In particular, they can look at their phenomenological equation and see what the measurements say about the energy scale of quantum gravity.

The energy scale of quantum gravity

At what scale should quantum gravity become important? We mentioned earlier that the Planck energy and Planck length might be the reasonable scales. One key reason to choose these scales is that they occur naturally as scales defined by the other various constants of nature such as the speed of light and the strength of gravity. Indeed, one way to look at this is to say that any other choice of energy or length scale would require justification. That is precisely the position particle physicists find themselves in as they try to understand why particles have the masses they have and why various phenomena seem to occur at particular energies. Particle physics doesn’t seem to live in the simplest possible world, so to solve those issues physicists need to invoke ideas like symmetry breaking and other concepts more complicated than what the simplest possible universe would require.

Conceptual arguments and choosing the simplest path forward implies that the appropriate scale to observe effects seems to be this Planck scale, and it is often represented by the Planck mass in the equations. (The Planck energy, length, and mass are all related to each by multiplying or dividing by constants of nature.)

If the dependence of speed on energy has the simplest form possible, then the time delay between high- and low-energy photons depends on the energy difference between them and an appropriate mass scale for quantum gravity. So by measuring the time delay and energy difference, physicists can determine limits on this mass scale and see whether it matches up with the expected Planck mass.

What the measurement says about the mass scale of quantum gravity

When the Fermi team did the calculations, using the most conservative estimates for how astrophysics plays into this, they determined that the mass scale must be at least 1.2 times the Planck mass, and by using reasonable but less conservative assumptions, they derived lower limits on the mass scale of up to 100 times the Planck mass. One way to interpret this is to say that there is no variation of the speed of light coming from any quantum gravity effects at less than 1.2 times the Planck mass. And given that some quantum gravity frameworks predict that effects should be showing up at that point, perhaps those models are simply wrong, and there is no changing speed of light.

There are, however, quite a few caveats. The limit on the mass scale is only true if the quantum gravity effects show up in the simplest possible phenomenology where the time difference is proportional to the energy difference scaled by the quantum gravity mass. Some models suggest that the time difference might be proportional to the square of the energy difference scaled by the quantum gravity mass. That would be a much smaller time difference and not observable in this kind of experiment.

Additionally, other quantum gravity models could still have quantized space-time but wouldn’t show an energy-dependent speed of light in this form. Instead, speed might depend on the polarization of the light (called birefringence, like the optical property of calcite crystals which create two images when you look through them). There are other options floating around as well.

To be fair to the claim, though, ruling out the simplest dependence of speed on energy at the expected Planck scale is a significant constraint on future theories of quantum gravity.

The future of quantum gravity theories

In one sense, this result doesn’t change a whole lot. None of the quantum gravity frameworks were really predicting concrete results so it is not really an explicit test of quantum gravity, nor does it rule out any particular frameworks. It does, however, provide guidance to theorists about what kinds of theories might be viable as they develop their ideas further, and that is pretty important to the field. Any experimental constraints are good constraints, especially as string theory is now in a position of predicting almost anything and this result limits some of the versions of string-like theory. Meanwhile, loop quantum gravity had a class of ideas that have now been ruled out.

What is particularly clear is that the technique of observing gamma-ray bursts is powerful for placing real observational limits on the kinds of predictions that quantum gravity can get away with. The Fermi Gamma-ray Space Telescope likely to see many more bursts that can even more tightly constrain quantum gravity theories and some theorists have suggested that combining the observations of gamma-ray bursts with neutrino observations, it might be possible to develop tighter constraints or even measurements of how much light speed changes with energy if the speed of light does indeed depend on energy.

Read more

Fermi Telescope Caps First Year With Glimpse of Space-Time — NASA press release, October 28, 2009
Constraining Modified Dispersion Relations with Gamma Ray Bursts — BackReaction blog, June 26, 2009
Prospects for constraining quantum gravity dispersion with near term observations — Preprint by Giovanni Amelino-Camelia and Lee Smolin, June 23, 2009

Update: Some other news coverage that has appeared since this was published

An intergalactic race in space and time — Nature (news section)
Quantum gravity theories wiped out by a gamma ray burst — ars technica (looks like it got the embargo time wrong so it came out early)
Special relativity passes key test — Physics World

NASA’s Fermi Gamma Ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

David Harris

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America’s accelerator future

October 27, 2009 | 10:27 pm

Director of the DOE Office of Science William Brinkman addresses the Accelerators for America's Future symposium in Washington, DC.

The next big thing in particle accelerators may not be so big, and it might not have anything to do with research into the subatomic secrets of the universe. Instead it could offer a better way to slice silicon into chips, treat cancer, stop terrorist attacks, tap new sources of energy, reduce the world’s growing burden of nuclear waste or turn air pollutants into fertilizer.

More than 400 people are in Washington, DC, this week to draw up a list of possibilities for the Office of High Energy Physics in the DOE’s Office of Science, which builds and operates America’s major research accelerators and funds research on accelerator technology. Called “Accelerators for America’s Future,” it kicked off Monday with an all-day symposium and continued Tuesday and today with invitation-only working groups focusing on industrial applications and production, national security, energy and the environment, medicine and biology, and discovery science. They’ll report their findings later.

What the Office of Science hopes to get from all this is a sense of what these various accelerator users need, both now and in the future; the major cost, technical and policy barriers they face; which areas of accelerator R&D hold the most promise; and how to bridge what one speaker called “the valley of death” between basic research and deploying a new technology, according to Dennis Kovar, associate director of the Office of Science for High Energy Physics. (You can find slides from his talk and other presentations here. )

Most of the public buzz about accelerators these days is focused on the Large Hadron Collider, the big underground ring beneath the Swiss-French border that will bring particles into collision with seven times more energy than any machine before. Although it will ramp up much more slowly than expected due to an accident last year that did considerable damage to its magnets, crews there injected particles into the collider last Friday and Saturday and are on track to restart in November. And the accomplishments of other research accelerators are well known, from revealing the constituents of the atom and the forces that hold them together to creating more than 25 new chemical elements, investigating high-temperature superconductors, and creating conditions in the laboratory that have not existed since shortly after the big bang.

But behind the scenes, smaller and more modest accelerators have been cutting big swaths through the lives of ordinary Americans.

For instance, “The argument’s been made that accelerators have saved more lives than any other biomedical device,” with an estimated 10,000 of them being used to treat cancer, Tom Katsouleas of Duke University told the audience.

More than 18,000 industrial accelerators have been built over the past half-century and most of them are still in use, according to a commentary by Robert W. Hamm in the Oct 09 issue of symmetry; they sterilize medical supplies, analyze materials, toughen the rubber in tires, play a key role in manufacturing the semiconductor chips at the hearts of electronic devices, and even create shink-wrap, among many other things.

Meanwhile, work at synchrotron lightsources–accelerator rings that produce bright beams of X-rays–has illuminated the structures of the rhinovirus that causes colds and 50,000 of the proteins that carry out critical functions in every living thing; how nerve cells function and insects breathe; and, after a 30-year-struggle, the structure of the ribosome, an exceeding complex snarl of molecules within our cells that builds proteins based on instructions encoded in DNA. That last discovery earned the Nobel Prize in Chemistry for three biologists this year, and in fact lightsources have become all-purpose tools for research in a number of fields.

None of this would have been possible without advances in accelerator technology that went hand-in-hand with basic research, said Maury Tigner of Cornell University, who is leading the working group focused on discovery science: “This is really a case of science driving technology driving science driving technology, which is the way that most of these sciences go forward.” He likened accelerators to modern ships of discovery: “They take us where we cannot go unaided, enable us to see what we cannot see unaided.”

In today’s economic climate, however, it’s especially challenging to make the case that the technology and the basic science are worth supporting, not only for the discoveries they enable but for the role they play in driving innovation and keeping America competitive.

That challenge came into sharp focus earlier this month at a hearing of the Subcommittee on Energy and the Environment of the House Science and Technology Committee; the American Institute of Physics’ FYI bulletin summarizes the main points here. Chairman Brian Baird of Washington, who is considered a strong supporter of science, said US tax dollars allocated to research facilities such as the Large Hadron Collider and other “big gizmos” could have been used to address pressing societal needs, and asked scientists how they could justify those expenditures.

“All of us in this room need to help answer those questions,” Fred Dylla, executive director and CEO of the American Institute of Physics, told the symposium on Monday.

William Brinkman, director of the DOE’s Office of Science, said new approaches are needed to bring down the cost of accelerators and create new paths to discovery.

“I believe we’re pushing hard on the limits of conventional accelerators today,” he said. With the proposed International Linear Collider estimated to cost on the order of $20 billion, “It’s starting to get to the point where the scientific community can’t afford these things.”

Brinkman cited several promising approaches that DOE-funded researchers are investigating, including a muon-muon collider, superconducting radiofrequency cavities for propelling particles along, and plasma wakefield acceleration, which has been shown to accelerate electrons to high energies in very short distances. (See “Crashing the size barrier” in the Oct 09 symmetry.) Although plasma wakefield acceleration is still a decade away from practical use, several speakers mentioned it as a promising development that could greatly decrease the cost and size of future accelerators for research, medicine and other applications.

Monday’s keynote talk was given by Norman Augustine, the retired chairman CEO of Lockheed Martin Corp. and chairman of the committee that produced the report Rising Above the Gathering Storm: Energizing and Employing America for a Brighter Economic Future for the National Academies of Science.

While the DOE is now on track to double its budget after decades of relatively flat funding for physical sciences, he said, much of this year’s increase came in the form of one-shot stimulus funding. “That implies, of course, that we’re going to fall off a cliff in about a year–the asteroid is going to hit–if we don’t make the case” that the physical sciences are critical for research in all fields, Augustine said.

With industry cutting back on basic research and universities facing draconian budget cuts, he said, it’s more important than ever for the government to fund university research and maintain federal laboratories that can deal with large-scale problems, perform high-risk research, build large facilities, plan for the long term and foster research that cuts across disciplines.

“If science is the keystone to the quality of life in the future, that’s a message we need to convey,” Augustine said. “I think it’s important to point out how broadly that impact is felt. People take for granted their iPods, their GPS, their laptops. Most don’t realize that it was people years ago, working in the field of quantum mechanics, that made all this possible.”

Glennda Chui

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LHC’s CMS collaboration submits first detector performance results

October 27, 2009 | 5:34 am

Author lists for experiments at the LHC can include thousands of names.

The CMS collaboration at CERN’s Large Hadron Collider has posted its first detector performance results to arXiv.org, and the paper’s author list could run as final credits for a feature film.

The collaboration acknowledges 2443 collaboration members in a list that takes up almost as many pages as the text of the paper.

“It just reflects the fact that experiments at the LHC are complicated,” said Joel Butler, US CMS program manager. “The number of people involved in an effort like this is huge.”

The CMS detector is one of the two main detectors at the Large Hadron Collider at CERN.

The paper’s author list credits not only the physicists involved in the study but also the engineers and technicians who made the study possible by designing and building the detector.

Building and using the large, complex machines scientists need to conduct high-energy physics experiments requires the cooperation of thousands of collaborators. The challenge of choosing whom to give credit once the experiment yields results has been a source of discussion.

“Inside the field, this inclusive approach works very well,” Butler said. “If we need to know who did the specific work reported in the paper, we can ask. The problem is when people in the field of high-energy physics have to be compared to people outside the field.”

It could be difficult for a high-energy physicist sharing credit with thousands of other scientists to compete for a position at a university against a solid-state physicist on a small experiment sharing the credit with fewer than five collaborators.

CMS has begun highlighting individuals’ work through awards, including a thesis award for students and special service awards for students and post docs.

“The thesis award is very competitive,” Butler said. “People whose theses are even close to the top are very impressive. The winning thesis is always awesome.”

Hundreds of graduate students and post docs contribute to the CMS experiment. “Highlighting their accomplishments is important for their future and the future of our field,” Butler said.

This first paper is only the beginning of the huge number of publications to come from the CMS experiment. Collaboration members have another 22 papers in the pipeline based on cosmic ray data from 2008 alone, Butler said. They discuss alignment, calibration, background noise, and other detector issues scientists can address based on their experiences studying cosmic rays.

The CMS collaboration’s first cosmic run paper explains how scientists aligned the detector’s silicon tracker using data from passing cosmic rays. The Journal of Instrumentation Science and Technology is considering the paper for publication.

The collaboration recently completed its 2009 cosmic ray run and awaits the first particle collisions from the LHC. More publications trailing lengthy author lists behind them are sure to follow.

Kathryn Grim

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Beam is back in the LHC

October 26, 2009 | 11:29 am

The first ion beam entering point 2 of the LHC, just before the ALICE detector, on 23 October 2009. Courtesy CERN.

CERN reports that beams of protons and lead ions were injected into the Large Hadron Collider this weekend. The beams made a partial tour of the LHC in both directions before being dumped. This marks the first time in more than a year that particles have entered the LHC, and the first time ever that lead ions traveled through part of the LHC.

On Friday, protons and lead ions traveled clockwise through the LHC, passing through the ALICE detector before being dumped. On Saturday, protons traveled counterclockwise through the LHCb detector. These injection tests allow the scientists and engineers working on the LHC to check that the various sectors are prepared for the particle beam and that the beam is stable. Rama Calaga of Brookhaven National Laboratory was among the scientists monitoring the tests. Calaga noted that these tests were “a spectacular success and there were no surprises.”

The CERN news item also has a photo of the first beam of lead ions entering the LHC.

-Daisy Yuhas

Symmetry Intern

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Imagine Science Film Festival

October 23, 2009 | 2:17 pm

Sometimes life sends you down one path, only to reveal that it was just the beginning of another. Alexis Gambis was well into his PhD work in biology when he realized he had a passion for film. Rather than divorce the two, Gambis brought them together and began making movies in his fruit fly lab at Rockefeller University.

Now a film student at NYU and a science teacher on the side, Gambis is also the founder of the Imagine Science Film Festival–taking place in New York City between October 15 and 26. In only its second year, the festival is screening mostly short films that include some element of science. But don’t dismiss it as a collection of the same-old science documentaries–the submissions are mostly fiction and narrative, and they blend science with storytelling in astoundingly creative ways. Gambis says his goal is to encourage filmmakers to use science as an element in their work, and as it turns out there are plenty of them who already do. The festival received nearly 300 submissions this year and will screen 50 (including four feature-length films).

The films at the festival include some narrative and some documentary, some live action and some animated, and some that combine genres and styles in amazing ways. You can see the complete 2009 movie list here. The submissions include a story about a man who is receiving messages from robots on how to save the world; an animated film based on testimony from people who have survived deep mental illnesses; a documentary following a graduate student working at the LHC; a love story based in probability, where a phone number written on a twenty dollar bill accidentally makes its way back into circulation before the hero can call his true love back; a biography of Alan Turing; and a film who’s description simply says, “What do scientists dream of?”

In only its second year, the festival has received a tremendous amount of press in New York and beyond, as well as support from major science organizations and publications. The festival is now a non-profit organization which relies on sponsor support and public donations. We’ll have minor coverage of this year’s festival and can’t wait to see what fantastic works of art it brings to our attention. Watch the festival’s neat trailer here.

Calla Cofield

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Astrophysically acronymical

October 22, 2009 | 10:31 am

HETDEX is gonna get a VIRUS and that’s not something you want to hear over lunch. But with an expert at the table to calm our potentially troubled stomachs, a group of seven science writers at the Annual meeting of the National Association of Science Writers and the Council for the Advancement of Science Writing learned a lot about a project to explore the slightly less stomach turning topic of dark energy.

Karl Gebhardt of the University of Texas at Austin brought us up to speed on the development of the Hobby-Eberly Telescope Dark Energy Experiment, or HETDEX. It’s an interesting project that is looking to understand dark energy in a slightly different way to how the majority of dark energy telescopes approach the problem. It differs because it looks further back in time, by observing fainter astronomical objects, further away from us. It’s a challenging experiment, because dark energy plays its most significant role in the universe’s evolution relatively recently, but looking further back in time allow HETDEX to answer a few different kinds of questions about dark energy.

And the VIRUS? Well, that’s the Visible Integral-field Replicable Unit Spectrograph. It consists of over 100 identical small units that each captures light in an array of optical fibers. By building the detector as a set of repeating units, the researchers can save considerable money (up to 75% by the scientists’ estimates) and still get the performance they need. The savings come because a single unit can be prototyped, tested, and fully developed, and then economies of scale mean that unit can be replicated relatively cheaply. As Karl said at the lunch, after a certain number are produced, the rest come essentially free.

One of the lunchers was Robert Irion, director of the science writing program at the University of California, Santa Cruz, and past long-time journalist for Science magazine. Rob was having fun with the often-extreme acronyms that astronomers create for their projects with some light-hearted teasing about HETDEX’s VIRUS, and proposed that what we really need was GROG. Yes, you already knew that was a General Relativistic Overturn of Gravity, didn’t you?

But to illuminate his point about “astronyms”, Rob later sent the lunch attendees a piece he had written for Science about five years ago but which never quite, he observed, saw the light of publication, due to a lack of space. (Yep, I’m trying to see how many subtle puns on optical astronomy I can slip into one sentence.)

So read the text below and if you feel like it is tinged just slightly red, that’s because it’s coming from the past…

Reporters at the recent American Astronomical Society meeting in Atlanta needed SMARTS to interpret the witty acronyms invented by astronomers for their pet projects. A FIRST look at the abstract volume turned up some DIRT and some real GEMS, so one writer went on a QUEST for the best–or worst–creations.

The DEEP search exposed some clever IDEAS, from trees (ASPENS) to desert (MOJAVE), and from ocean (SCUBA) to movie EPICs (SAURON). Some scientists couldn’t quite spell (KASCADE), making one wonder whether they were on LSD. (At the very least, they were all WET.)

The ARCADE-like poster room was a veritable hall of BEASTs. One could GLIMPSE CANGAROOs, EGRETs, FLAMINGOS, GNATs, and even OGLE a fine BASS. A few astronomers, burdened by strained acronyms, stood at their posters with MACHO GLAREs. Others smiled to some internal MUSYC, confident in the DESTINY of their proposals.

When it came down to the WIRE, the writer blew a FUSE trying to pick the one acronym that really SINGS. For a COMPLETE list, SEGUE to this web page*. If that’s too much to ask, don’t shoot the MESSENGER.

* Editor’s note: This link doesn’t exist as the piece was never published, but it would have linked to the text below.

SMARTS: Small and Moderate Aperture Research Telescope System

FIRST: Faint Images of the Radio Sky at Twenty centimeters

DIRT: Dust InfraRed Toolbox

GEMS: Galaxy Evolution from Morphology and Spectral energy distributions

QUEST: QUasar Equatorial Survey Team

DEEP: Deep Extragalactic Evolutionary Probe

IDEAS: Initiative to Develop Education through Astronomy and Space science

ASPENS: Astrometric Search for Planets Encircling Nearby Stars

MOJAVE: Monitoring Of Jets in AGN with VLBA Experiments

SCUBA: Submillimeter Common User Bolometer Array

EPIC: European Photon Imaging Cameras

SAURON: Spectroscopic Areal Unit for Research on Optical Nebulae

KASCADE: KArlsruhe Shower Core and Array DEtector

LSD: Lenses Structure and Dynamics

WET: Whole Earth Telescope

ARCADE: Absolute Radiometer for Cosmic And Diffuse Emission

BEAST: Background Emission Anisotropy Scanning Telescope

GLIMPSE: Galactic Legacy Infrared Mid-Plane Survey Extraordinaire

CANGAROO: Collaboration of Australia and Nippon for a GAmma Ray Observatory in the Outback

EGRET: Energetic Gamma Ray Experiment Telescope

FLAMINGOS: FLoridA Multi-object Imaging Near-infrared Grism Observational Spectrometer

GNAT: Global Network of Astronomical Telescopes

OGLE: Optical Gravitational Lensing Experiment

BASS: Broadband Array Spectrograph System

MACHO: MAssive Compact Halo Object

GLARE: Gemini Lyman-Alpha at Reionization Era

MUSYC: MUltiwavelength Survey by Yale and Chile

DESTINY: Dark Energy Space Telescope (hey, what about INY?)

WIRE: Wide-field InfraRed Explorer

FUSE: Far Ultraviolet Spectroscopic Explorer

SINGS: SIRTF (now Spitzer) Infrared Nearby Galaxies Survey

COMPLETE: COordinated Molecular Probe Line Extinction Thermal Emission survey

SEGUE: Sloan Extension for Galactic Underpinnings and Evolution

MESSENGER: MErcury Surface, Space ENvironment, GEochemistry, and Ranging mission

Of course, I wouldn’t want to give the astronomers and astrophysicists too hard a time over their naming. Particle physicists are just as bad. Travel nearly five years back in time with symmetry magazine to read a feature about the woeful naming of projects in particle physics.

Thanks to Rob Irion for sharing this piece with us.

David Harris

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New print issue of symmetry, also online

October 21, 2009 | 11:39 am

In the October 2009 issue of symmetry, meet Ketino Kaadze, Mark Cooke, and Martina Hurwitz, three graduate students who recently left experiments at CERN's Large Hadron Collider to work on data-producing experiments at Fermilab's Tevatron.

The latest issue of symmetry is on its way to subscribers and the entire content of the issue is online.

This issue features many stories about accelerator development and comes out just before the Accelerators for America’s Future symposium next week in Washington, DC.

In the issue, read about how accelerators are being used to clean up sewage sludge and industrial flue gases, the range of industrial applications of accelerator technology, and steps toward the next generation of acceleration technology using plasma wakefields.

We show how the types and capabilities of accelerators have evolved over the past 80 years in an updated version of a classic graphical representation, introduce the making of shrink wrap as another unusual aspect of accelerator tech, and comment on how accelerators find themselves in an unusual place in science, straddling  basic and applied research.

There is plenty else to discover in the issue but let us know what you think!

David Harris

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Next-gen telescope to use new calibration techniques to extend science reach

October 19, 2009 | 1:46 pm

Editor’s note: The story previously published here under the headline “Next-gen dark energy telescope might deliver images in real time” has been removed. Following publication, other members, including the leadership, of the LSST collaboration informed us that the descriptions by a quoted LSST collaborator did not accurately reflect the project. As such, the main thrust and headline of the article are no longer supportable. There is some very interesting work taking place on LSST regarding new techniques for calibration of data to maximize the science reach of the survey, and we plan to cover that work in the future.

David Harris

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Galileo's "falling bodies" experiment re-created at Pisa

October 17, 2009 | 6:36 am

Perhaps the most famous experiment in physics is Galileo’s effort to demonstrate that the rate of falling of a body is independent of its mass by dropping objects from the top of the leaning tower of Pisa. Galileo might not have actually ever done the experiment but it’s a core part of the story of the history of physics.

Science writer Dan Falk attended physicist Steve Shore’s re-creation of the event at the tower and made the video below. He warned me that he gives a simplified explanation of the effects of air resistance; because of the link between the speed of a object and the amount of air resistance, a bowling ball would fall faster than a volleyball, contrary to what Dan suggests in his narration-but the thrust of the argument is OK.

So what will happen in real world conditions? Does the effect of mass cancel out as it would if there were no air resistance? Or does the way that the force of air resistance has a different dependence on mass to the force due to gravity mean that the heavier objects will fall faster? And what would happen when the objects are identical in shape but with different masses? In his experiment, Shore used bottles of different sizes, filled with water.

Make a prediction about the results before you watch the video. Whatever you predict, you know you’ll see a big splat at the end!

David Harris

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