Top Ten Observatories

This is a list of the 10 greatest modern astronomical observatories ever imagined. Some are being built presently, some are scouring for funding, and some are dreams. They are in no precise order, but I have tried to place them according to their extremeness with respect to scientific impact, cost, technology, and size.

1. Laser Interferometer Space Antenna

LISA is in a class of its own.  In some sense it does not belong on this list because it literally transcends every other observatory on this list by monitoring the universe through gravitational waves and not electromagnetic waves.  If LISA is successful it will be the first direct observation (unless a project like advanced LIGO beats it to the punch) of gravitational waves which are predicted by Einstein's theory of General Relativity. LISA will detect the variation in distance of three spacecraft flying in an equilateral triangle formation. The LISA instruments are classic interferometers sensitive to gravitational  waves which distort the space-time between the spacecraft by as little as just tens of pm. Soon the LISA Pathfinder mission will be launched to prove the concept and technology necessary for the complete observatory. LISA is a profound step forward for humankind, like an infant opening its eyes for the first time.

2. Terrestrial Planet Finder

The TPF is visionary space mission which will likely consist of two observatories in space a coronagraph and an interferometer array.  The TPF will search for extrasolar terrestrial planets around relatively close stars like the Alpha Centauri system and systems where the probability to find an extra solar planet is high.  The coronagraph would be a very large optical telescope, at least three times that of Hubble, that would also have special optics to occult the light of bright stars in order to see the dim planets next to their brilliant host stars.  The interferometer, illustrated above, would consist of several small infrared telescopes orbiting in formation; the interferometric technique would allow the telescopes to obtain a resolution of a much larger telescope.

3. James Webb Space Telescope

The JWST is considered the successor to the Hubble Space Telescope.  It will study galaxy, star and planet formation in the Universe with supreme depth and precision.  Just imagine the James Webb Ultra Deep Field. The telescope engineering is impressive.  The telescope's primary mirror will consist of a 6.5 m (about 6 times the area of Hubble) gold coated beryllium refelector composed of 18 hexagonal segments which will unfold in space. The mirror is made of such special materials because of the need for specific thermal and reflective properties. For example beryllium is the metal with the greatest heat dissipation characteristics per unit weight and further its relatively low coefficient of thermal expansion imparts stability to the mirror.  JWST is designed to observe very distant objects such that much of their light will be in the infrared when it reaches the telescope and therefore JWST will be an infrared telescope, hence the gold coated reflecting surface.  JWST is packed with advanced technology like hemispherical resonator gyros which should last longer than the traditional mechanical gyroscopes which were on Hubble and needed servicing during missions. This is necessary because JWST will be far from earth at Lagrange point two, some 1.5 million km from Earth and not close enough for simple repair missions. If all this sounds ambitious and outlandish that is because it is, but the science that the JWST will produce will certainly justify the effort.

4. Overwhelmingly Large Telescope

The OWL is the most unlikely telescope on this list; the project has been eclipsed by the European Extremely Large Telescope, the EELT, on all practical accounts. The OWL would be a unrealistically large 100 m telescope allowing it to observe objects as faint as an apparent magnitude of 38.  In order to control costs the OWL would be based on mass production of major cost items like the structural components and segmented mirrors, but a review panel determined the cost would be at least 1.2 billion Euros. This cost is considered unacceptably high.

5. The Square Kilometer Array

The SKA will be a radio telescope with a million kilometers of collecting area. It will be the largest telescope ever created and perhaps the most expensive at 1.5 billion Euro. The SKA will probe the gaseous component of the early Universe with sensitivity 50 times greater than the Very Large Array. This sensitivity and a wide field of view will also allowing the SKA to probe general relativity by monitoring the timing of a network of pulsars. Like the VLA the SKA will be an interferometric array consisting individual antenna stations working together to synthesize an aperture with a diameter up to several thousand kilometers.  Many things about the final design for the SKA are uncertain, in fact factions within astronomy have threatened to doom the entire project. The disagreements stem from different opinions on what the primary scientific objectives should be for the project. Currently it is planned that approximately 50% of the collecting area would be contained in a dense central array of 5 km in diameter to provide high brightness sensitivity at arc-second scale resolution for studies of faint spectral lines from structures in the early universe. Another 25% of the collecting area would be located within a diameter of 150 km; the image above shows a possible layout for the array with arms in a spiral pattern with a diamter of 150 km. The remainng 25% of the collecting area would be at baselines of 3000 km or greater. The distribution of antennas directly impacts what kind of science can be accomplished. The video below shows a possible layout for the SKA in dramatic fashion.

6. European Extremely Large Telescope

The EELT is the realistic result of the OWL telescope proposal. The primary mirror will be 42 meters consisting of 984 1.4 meter segments of only 50 mm thickness.  The mirrors are thin in order to have excellent thermal properties. The EELT will have an adaptive optics system which will perform active adjustment of a 2.5 meter mirror to compensate for atmospheric affects which distort images. There will be 5000 actuators supporting this mirror which precisely adjust the mirror's shape thousands of times per second in order to correct images.  The reality is that the limiting effect on all large ground based telescopes is atmospheric seeing, therefore all the ground based optical telescopes on this list use some kind of adaptive optics.

7. Large Synoptic Survey Telescope

The LSST is an 8-meter telescope with a 3 degree field of view (consider that the moon is only half a degree in the sky).  This design configuration allows the LSST to implement an observing program that detects near-Earth objects which are small and faint in exposures of 10 or 20 seconds, and it allows images to be stacked for deep and wide imaging for star and galaxy surveys. The science mission drivers of LSST include the nature of dark energy, the solar system, optical transients, and galactic structure. It is the LSST technology and the rate at which it will produce data that makes it so remarkable. The LSST camera is 3200 Megapixels (it is a giant array of 189 CCD chips) and will create 400,000 sixteen Megapixel images per night (resulting in about 30 TB) for a total of 60 PB of raw data over 10 years. The total data volume after processing will be over 100 PB requiring 250 TFlops of computing power for processing. LSST will be wide, fast, and deep. It should be ready for first light by 2014.

8. Thirty Meter Telescope

The TMT is another extremely large ground based telescope. Its design calls for a collecting area that is thirty meters or about 100 feet in diameter. In order to better explore the early universe it will be sensitive to light in the optical near infrared. Relative to the Hubble the TMT will have 144 times more collecting area and a factor of 10 better spatial resolution in the near-infrared. The TMT will have a primary mirror composed of 492 segments with a rotating tertiary mirror (as seen in the above image, a Ritchey-Chretien telescope) in order to direct light onto multiple instruments and it will of course use adaptive optics to correct for turbulence in earth's atmosphere. The TMT will implement a scaled of version of the segmented mirror technology of the Keck telescopes at a size which will produce significant science at a reasonable cost.

9. Giant Magellan Telescope

The GMT differentiates itself from the other giant ground based telescopes on this list in that its primary mirror will not be segmented in the standard manner, but will instead consist of seven monolithic 8.4 m mirrors.  Because six of the mirrors are off-axis (they don't focus light to a point directly above them, but rather to a point off to their side; see image above) they present a unique engineering challenge that will synthesize a telescope with a resolving power of a single 24.5 m mirror.  Currently the first mirror has been cast at the Steward Observatory Mirror Lab as a proof of concept that an acceptably accurate shape can be achieved.

10. Atacma Large Submillimeter Array

ALMA is probably the most practical observatory on this list and it is almost already completed (located in the Atacama desert), whereas many of the other observatories on this list are only the twinkle in astronomer's eyes. It is currently under construction in the thin (altitude of 5,000 m or 16,000 feet), dry air, of northern Chile. ALMA is not actually a single telescope, but an array of 50 (this number may change and has already been reduced once) antennae working in unison. It merits a place on this list because it will revolutionize astronomy by providing a senstive eye on mm wavelength light where early universe star/planet formation can be viewed best. Each of its 12 m antennas will observe in bands ranging fom 30 Ghz to 1 Thz and the array will have specialized telescope transporters which will enable baselines ranging from 150 m to 16 km. ALMA is only practical in respect to the grandiose telescopes on this list; it the the most ambitious ground-based telescope ever built and costs in excess of one billion US dollars.

The future of great astronomical observatories

This list is merely my musings on astronomical observatories. There are more productive observatories that have already built, or will be built, but these are the most exciting in my humble opinion. This list does not include even more speculative projects such as plans for a lunar radio telescope or an extremely sensitive and larger LISA. There are other planned observatories not mentioned, like IXO, that just didn't make the list.

It is of note that there is an over arching principle of segmentation present in all of these observatories; these telescopes use multiple almost identical components working in unison in order to gather signal. LISA, the SKA, TPF, and ALMA use interferometry or correlation to observe. The EELT, TMT, JWST, use segmented primary mirrors. GMT uses several identical mirrors to simulate one primary mirror. LSST uses a massive array of CCD detectors. Modern technology and the economic/complexity benefits of reproducible industrial construction make this possible, but it takes modern computing to gather the data from the individual receiving elements and produce coherent observations and science.

To Hold The Sky

Galaxy Zoo 2

Galaxy Zoo is the worlds largest astronomy collaboration with over a hundred thousand collaborators. I mentioned Galaxy Zoo some time ago, but since then they have doubled the number of papers published from their collaboration and launched Galaxy Zoo 2. I want to discuss the impetus, implementation, and some of the results of the project here. It begins with the desire of astronomers to classify galaxies. And why would you want to classify galaxies? Well in order to learn about the cosmos, that is to learn about the properties of merging galaxies in the local universe, to learn about galaxy star formation, or to learn about the intrinsic spin of galaxies in our universe you may need to classify galaxies. The Galaxy Zoo collaboration has implemented the citizen science or crowd sourcing model in order to classify the million or so images of galaxies taken by robotic telescopes (like the Sloan Digital Sky Survey, SDSS, which produces images just like those seen here). Many years ago astronomers only had to inspect astronomical images by eye from photographic plates. The digital revolution has brought computers to bear on the problem as astronomers have implemented machine learning techniques such as neural networks in order to identify spiral from elliptical galaxies, but approaches like nueral networks are still limited by their training set size and are prone to errors. So as robotic survey telescopes have allowed us to gather a fantastic amounts of data technology has not been so successful at making sense of that data.

There have been several successful models for citizen science at home such Seti at Home and Folding at Home, but the most powerful computational device most people have at home is their own mind. The wisdom of crowds had already come to bear on one astronomical project, Stardust at Home, so galaxy classification was a natural application for citizen science. The Galaxy Zoo team had a simple approach to galaxy classification they implemented in Galaxy Zoo 1. They offer the user a single image, like those seen above, of a galaxy and 6 buttons:

The buttons are as follows: 1) Elliptical galaxy, 2) Clockwise spiral, 3) Anti-clockwise spiral,  4) Spiral Galaxy Other e.g. Edge on, Unsure, 5) Star or Don't Know, 6) Merger.  The system receives back a classification, but they show the same galaxy to many users such that they get multiple classifications for a single galaxy. The result of the multiple classifications for each galaxy is is statistical certainty. Even trained astronomers make mistakes and disagree on the classification of some galaxies therefore having many amateurs classify a galaxy is better than a few professional astronomers. The system they have developed is also quite sensitive to user idiosyncrasy with respect to the fact that they monitor user performance for individual tasks such as ability to identify galaxy bulges or spiral arms and then weight that user's responses according to their accuracy and consistency for each task. The great thing about having people's eyes on the data is that unexpected and unique discoveries are made possible. Computers make errors not discoveries.  The fantastic support for the project is very encouraging. They did a survey of over 10,000 users to discover their motivation. The most important motivator across all age groups was:

I want to contribute to science

The Cosmos isn't strange people are strange

All those good willed people, what could possibly go wrong? The Galaxy Zoo published a paper on the Chiral correlation function of galaxy spins, that is they investigate if spiral galaxies have a tendency to spin clockwise or counterclockwise, and they discovered more about people than galaxies. If galaxies had a spin tendency it would quite simply undermine physics because chirality is a fundamental property of particles and cosmology. Indeed they found a tendency for galaxies to spin counterclockwise, but when they began to display the mirrored images of the galaxies (expecting to receive more clockwise responses this time) they found the users behavior to be inconsistent.  This indicates that either people are strange or the user interface of Galaxy Zoo is strange. They sum up the results in their abstract:

After establishing and correcting for a certain level of bias in our handedness results we find the winding sense of the galaxies to be consistent with statistical isotropy. In particular we find no significant dipole signal, and thus no evidence for overall preferred handedness of the Universe.

This may seem like an obvious result because it is intuitively correct, but it is important to verify observationally what seems intuitively correct and further previous studies had found evidence for non statistical isotropy.

Hanny's Voorwerp

The unique discovery of Hanny's Voorwerp was made possible only by the citizen scientists of the project. Hanny's Voorwerp is a green amoeba like blob next to a spiral galaxy that was discovered by a galaxy zoo volunteer, Hanny van Arkel, and hence the name of the object.  It appears green in some optical images because of bright emission lines that dominate in the SDDS g band. Spectral analyis has shown that it is a highly ionized region leading to the hypothesis that it is the result of a powerful transient outburst because whatever energized the blob is now gone. Researchers hypothesize that Hanny's Voorwerp is a quasar light echo:

Hanny’s Voorwerp, is bright in the SDSS g band due to unusually strong [OIII] 4959, 5007 emission lines. We present the results of the first targeted observations of the object in the optical, UV and X-ray, which show that the object contains highly ionized gas. Although the line ratios are similar to extended emission-line regions near luminous AGN, the source of this ionization is not apparent. The emission-line properties, and lack of x-ray emission from IC 2497, suggest either a highly obscured AGN with a novel geometry arranged to allow photoionization of the object but not the galaxy’s own circumnuclear gas, or, as we argue, the first detection of a quasar light echo. In this case, either the luminosity of the central source has decreased dramatically or else the obscuration in the system has increased within 10⁵ years. This object may thus represent the first direct probe of quasar history on these timescales.

Galaxy Zoo 2: Mergers

The result of users classifying galaxies as mergers were 3000 prime candidates with which they wanted to compare to simulations. The goal of Galaxy Zoo 2 is to understand cosmic mergers. They use the crowd source model again because this allows exploring the entire parameter space quickly whereas a machine may often find a local solution, but would be limited in knowledge of  unique solutions. Galaxy Zoo 2 presents you, the user, with a 3x3 grid of galaxies. At the center is a real image of a galaxy and surrounding it are 8 simulated galaxies. You must select which simulations match the real image best. If you don't like any of your options you can click a button at the top and you get a slot machine effect of 8 new galaxies.  It is very satisfying to demand random sets of galaxies and wait for a winner that matches what you are looking for. I found myself looking at upwards of 500 galaxies for each galaxy merger I classified which sounds absurd until you try it and see how easy it is. After selecting a few galaxies you can fine tune your selected simulations within parameter space and then select your final best simulation. The entire application runs the simluations locally on the user's machine in Java so the Zoo leverages everything a user has to offer from their computer's CPU to their brain.

Science Zoo

There are more Zoos in development. Moon Zoo is coming soon which will be like Galaxy Zoo for classifying features on the lunar surface using high resolution images from the Lunar Reconnaissance Orbiter Camera. Other fields will also be using the Zoo model, but surely astronomy offers the most exciting and beautiful possibilities. Astronomy is facing a flood of data soon with next generation projects like the Large Synoptic Telescope coming online in a few years. LSST will produce some 30 terabytes of data a night. This may be such a large amount of data that volunteers wont be able to sift through it all. In this case volunteers could provide the training sets for machine learning systems that could accurately classify data. The Zoo model will continue because people want to contribute to science.


References:

Anze Slosar, Kate Land, Steven Bamford, Chris Lintott, Dan Andreescu, Phil Murray, Robert Nichol, M. Jordan Raddick, Kevin Schawinski, Alex Szalay, Daniel Thomas, & Jan Vandenberg (2008). Galaxy Zoo: Chiral correlation function of galaxy spins MNRAS, 392 (1225) arXiv: 0809.0717v2

Chris Lintott, Kevin Schawinski, William Keel, Hanny van Arkel, Nicola Bennert, Edward Edmondson, Daniel Thomas, Daniel Smith, Peter Herbert, Matt Jarvis, Shanil Virani, Dan Andreescu, Steven Bamford, Kate Land, Phil Murray, Robert Nichol, Jordan Raddick, Anze Slosar, Alex Szalay, & Jan Vandenberg (2009). Galaxy Zoo : 'Hanny's Voorwerp', a quasar light echo? MNRAS arXiv: 0906.5304v1

The Large Hadron Collider

The Large Hadron Collider, the LHC, has booted up. Today they circulated two counter-rotating beams and detected particle collisions in various detectors. This is great news and honestly I have been reluctant to mention too much about the LHC only for fear of disappointment, but I think this time it is the real deal. It is hard not to get excited about the LHC. It is not an exaggeration to claim that the LHC is the largest and most complex machine ever built by humans. Here is a brief introduction to the LHC through some media:

BBC Horizons: The Six Billion Dollar Machine

Also see part 2 and part 3 of the documentary.

3D tour of LHC

A 3D virtual tour of the LHC by Peter McCready begins to give an impression of the scope of the machine.

Brian Cox on CERN's Supercollider

Brian Cox gives a particularly smooth discussion for the impetus for the LHC in this TED talk:

Catastrophic Failure

I am not talking about microscopic black holes and the destruction of earth or all that nonsense, but various failures of the experiment itself. The reason I am hesitant about the LHC is because it is a complicated experiment so expecting proper performance and much less results any time soon is unrealistic. Last September the LHC broke down while ramping up current in the superconducting magnets that guide the beam. Precisely what happened leading to catastrophic failure was rather simple. There are connections between the superconducting magnets which can hold up to 12000 amps and their resistance is maintained at one billionth of an ohm, however, the resistance was some 200 times larger on the failed conductor connection. An electric arc broke out and the super fluid helium coolant was heated. A pressure wave resulted as and the helium warmed and expanded inflicting collateral damage on 53 (of 1232 total) other magnets nearby. There are 20,000 such connectors to rely on to ensure the proper function.  The LHC news explains:

Future Discovery

In the future I would like to discuss some of the implications of what the LHC may find. Consider this though: not finding what we are looking for, namely the Higgs boson, may be the most exciting discovery of all.

Landing on Titan

This strange movie is a visual aggregation of the data which the Huygens lander gathered when landing on Saturn's moon Titan on January 14th 2005. Huygens is part of the wildly succsesful Cassini-Huygens mission. Cassini is still taking fantastic pictures of Saturn and its moons while Huygens ended its journey on a methane riverbed and claims honors as the most distant touch-down ever made by a human built spacecraft. To the right here you can see the orange image that Huygens had as it came to rest stranded on the cold world; the rocks in the image are actually water ice. And further to the right is the grey image of a similary scaled image for comparison to the Moon's surface. I was struck by the flashing lights and strange sounds in the video. Every detail of the video expresses some aspect of the spacecrafts data aquisition. For a complete description of the data try this and here is an explanation for the sounds.

Sounds from a left speaker trace Huygens' motion, with tones changing with rotational speed and the tilt of the parachute. There are also clicks that clock the rotational counter, as well as sounds for the probe's heat shield hitting Titan's atmosphere, parachute deployments, heat shield release, jettison of the DISR cover and touch-down.

 Sounds from a right speaker go with DISR activity. There's a continuous tone that represents the strength of Huygens' signal to Cassini. Then there are 13 different chimes - one for each of DISR's 13 different science parts - that keep time with flashing-white-dot exposure counters.

A man of Seville

A man of Seville is shaved by the Barber of Seville if and only if the man does not shave himself. Does the barber shave himself?

Image from LOGICOMIX by Apostolos Doxiadis.

Leonids

The Leonids meteor shower by RG Photo.

The Leonid meteor shower peaks tonight in the early hours of this Tuesday morning.  The Leonids result from the earth's passage through debris left from comet Temple-Tuttle.  I would go into all this further, but the forecast for Seattle is rainy and cloudy for the next week, but perhaps you will have more luck observing the Leonids.  It should be a sight, around 500 meteors per hour, but it wont compare to the 1833 Leonid meteor shower:

One estimate was that over 240,000 meteors fell during that period, so many meteors in the sky at a time that many people were woken from their beds and stared at the sky in panic, believing the sky to be on fire. Many feared that it was the end of the world and dreaded what they would see at daybreak.

Update: I should clarify that when I refer to debris left by Temple-Tuttle I am referring to debris left by Temple-Tuttle's previous close passages to the sun which may have occurred long ago. For example the most recent close passage of Temple-Tuttle to the sun was 1998, but most of the meteorites seen in this shower were left by debris trails originating from passages in 1466 and 1533.  And finally here is a cool meteor detector that works by detecting reflected radio waves from the ionized trails created by particles of rock entering the upper atmosphere.

Invictus

Out of the night that covers me,
Black as the Pit from pole to pole,
I thank whatever gods may be
For my unconquerable soul.

In the fell clutch of circumstance
I have not winced nor cried aloud.
Under the bludgeonings of chance
My head is bloody, but unbowed.

Beyond this place of wrath and tears
Looms but the Horror of the shade,
And yet the menace of the years
Finds and shall find me unafraid.

It matters not how strait the gate,
How charged with punishments the scroll
I am the master of my fate:
I am the captain of my soul.

Detexify: Dymistify your LaTeX symbol

I write a lot in LaTeX and I forget a lot of obscure symbols I need. The solution: Detexify.  Detexify will discover the LaTeX formatting of any symbol you can manage to scrawl with your mouse. If you don't know what LaTex is then your probably not in academia, a student, or a publisher; it is a digital typesetting package.  Ignore this then and move along, otherwise I ask you...
How else would you learn about: \bat

Or have a little: \Heart

Or make real numbers: \Re

Or that one symbol you can't remember: \Denarius

And who can remember angstroms: \aa


Detexify is the work of Daniel Kirsch.  There is an iphone app too, but I am trying to figure out who has LaTex on their iphone?

Punctuation, Grammar, Style

I place content over punctuation, grammar, or style. I say who cares if their not using they're grammar correctly if your not using you're grammar correctly? Well, today I am grading students midterms and I find it amazing how some insist on using MLA style to hide answers. Why can't they just write the number down? Perhaps, because the MLA has strict rules for these cases:

• If your topic makes little use of numbers, "you may spell out numbers written one or two words" (Gibaldi 98). Otherwise, use arabic numerals. 

• If your writing contains the recurrent use of numeric statistical or scientific data, use numerals for those numbers but write out other numbers in the text if you can do so in one or two words. 

• Do not mix numbers that are spelled out with symbols, write out the term for the symbols as well. For example, write: 45%, or forty-five percent; $20 or twenty dollars.

There are times and places where formal punctuation, grammar, or style are not called for and I think those times include numerical responses and singing.

The Jodcast

I want to give a shout out to The Jodcast.  The Jodcast is an audio podcast about astronomy by astronomers at the University of Manchester's Jodrell Bank telescope. It discusses current science in twice-monthly shows.  They are great for listening to during commute or whenever, and you can subscribe for free of course on their website or here.  If you are a scientist and want to stay up on astronomy news, this is a powerful resource, so powerful that if you follow it regularly you will probably be more broadly aware of astronomy news than most astronomers.  Enjoy.

Explosive Morals: War Profiteer

Image from The Hurt Locker.

Jim Mitchell is a war profiteer.  He is the head of London based ATSC which sells, basically, dowsing rods for finding explosives.  The Iraqi government is spending millions to purchase the devices for use at military checkpoints.  The devices really are quite magical, from the New York Times:

ATSC’s promotional material claims that its device can find guns, ammunition, drugs, truffles, human bodies and even contraband ivory at distances up to a kilometer, underground, through walls, underwater or even from airplanes three miles high. The device works on “electrostatic magnetic ion attraction,” ATSC says.

I am incensed by this electrostatic magnetic ion attraction device's outrageously unrealistic claims.  I would go into the physics of magnetic ions, but if you have ever used an Ouija board you understand already.  The real forces at work here are sociological, variable reinforcement conditioning is a powerful way to shape behavior; it is the reason that baseball players have absurd rituals before games and why even apparently logical people have illogical superstitions.  In this case if the device doesn't work it is explained as user error and when it does work it is the life saver.  In reality Iraqi soldiers are simply relying on their intuition to perceive threats.  Studies show the device performs no better than random chance.  People are dieing and we can do better.  Let's get the word out about this situation.  The people profiting from this need to get what is coming to them.  I have a feeling there will be blood before the dust settles. More from the article:

Despite major bombings that have rattled the nation, and fears of rising violence as American troops withdraw, Iraq’s security forces have been relying on a device to detect bombs and weapons that the United States military and technical experts say is useless.

The sensor device, known as the ADE 651, from $16,500 to $60,000 each. Iraq has bought more than 1,500 of the devices.
The small hand-held wand, with a telescopic antenna on a swivel, is being used at hundreds of checkpoints in Iraq. But the device works “on the same principle as a Ouija board” — the power of suggestion — said a retired United States Air Force officer, Lt. Col. Hal Bidlack, who described the wand as nothing more than an explosives divining rod.

Still, the Iraqi government has purchased more than 1,500 of the devices, known as the ADE 651, at costs from $16,500 to $60,000 each. Nearly every police checkpoint, and many Iraqi military checkpoints, have one of the devices, which are now normally used in place of physical inspections of vehicles.

With violence dropping in the past two years, Prime Minister Nuri Kamal al-Maliki has taken down blast walls along dozens of streets, and he contends that Iraqis will safeguard the nation as American troops leave.

But the recent bombings of government buildings here have underscored how precarious Iraq remains, especially with the coming parliamentary elections and the violence expected to accompany them.

The suicide bombers who managed to get two tons of explosives into downtown Baghdad on Oct. 25, killing 155 people and destroying three ministries, had to pass at least one checkpoint where the ADE 651 is typically deployed, judging from surveillance videos released by Baghdad’s provincial governor. The American military does not use the devices. “I don’t believe there’s a magic wand that can detect explosives,” said Maj. Gen. Richard J. Rowe Jr., who oversees Iraqi police training for the American military. “If there was, we would all be using it. I have no confidence that these work.”

The Iraqis, however, believe passionately in them. “Whether it’s magic or scientific, what I care about is it detects bombs,” said Maj. Gen. Jehad al-Jabiri, head of the Ministry of the Interior’s General Directorate for Combating Explosives.

Dale Murray, head of the National Explosive Engineering Sciences Security Center at Sandia Labs, which does testing for the Department of Defense, said the center had “tested several devices in this category, and none have ever performed better than random chance.”

Read on...

Eve of All Hallows

Olaf Breuning with skeletons in the garden of Villa Medici, Rome (2002).

Gamma Ray Bursts Place Limit on Quantum Gravity

The right-most panel shows the discovery image made using the UKIRT Wide Field Infrared Camera with the K filter (centred at 2.15 μm) at a mid-time of about 30 min after the burst. The other three images (Y, 1.02 μm; J, 1.26 μm; H, 1.65  μm) were obtained approximately 1.5 h after the burst using Gemini North's Near Infrared Imager and Spectrometer (NIRI). The main panels are 40 arcsec to a side, oriented with north to the top and east to the left. Insets, regions around the GRB, smoothed and at higher contrast. The absence of any flux in Y implies a power-law spectral slope between Y and J steeper than F_ν  ∝ ν^-18 and, coupled with the blue colour at longer wavelengths (J-H(AB) ≈ 0.15 mag), immediately implies a redshift greater than about 7.8 for GRB 090423. Image credit: Nature.

In June the Fermi telescope detected a distant gamma ray burst (GRB) at a redshift of 8.2 which was called at the time the most distant object ever observed.  Today Nature has published papers on some of the results from the Fermi team. Here is a quick look at them; first up is that distant object GRB 090423, A gamma-ray burst at a redshift of  z=8.2.

Long-duration γ-ray bursts (GRBs) are thought to result from the explosions of certain massive stars, and some are bright enough that they should be observable out to redshifts of z > 20 using current technology. Hitherto, the highest redshift measured for any object was z = 6.96, for a Lyman-α emitting galaxy. Here we report that GRB 090423 lies at a redshift of z  ≈ 8.2, implying that massive stars were being produced and dying as GRBs ~630 Myr after the Big Bang. The burst also pinpoints the location of its host galaxy.

Another paper published today explores a tantalizing prospect for physicists: the unification of general relativity and quantum field theory, which seem to be fundamentally incompatible.  The observation of a single photon at ~31 GeV from GRB 090510 places limits on quantum gravity which predicts that Lorentz invariance breaks down at the Planck length.  This would cause different energy photons to travel at different speeds.  Observations of varied speeds of photons from GRB 090510 were not convincingly seen putting a damper on quantum-gravity theories. The Fermi team has gone on to derive A limit on the variation of the speed of light arising from quantum gravity effect .

A cornerstone of Einstein's special relativity is Lorentz invariance—the postulate that all observers measure exactly the same speed of light in vacuum, independent of photon-energy. While special relativity assumes that there is no fundamental length-scale associated with such invariance, there is a fundamental scale (the Planck scale, l_Planck  ≈ 1.62 ~ 10^-33 cm or E_Planck = M_Planckc² ≈ 1.22 x 10¹⁹ GeV), at which quantum effects are expected to strongly affect the nature of space–time. There is great interest in the (not yet validated) idea that Lorentz invariance might break near the Planck scale. A key test of such violation of Lorentz invariance is a possible variation of photon speed with energy. Even a tiny variation in photon speed, when accumulated over cosmological light-travel times, may be revealed by observing sharp features in γ-ray burst (GRB) light-curves. Here we report the detection of emission up to ~31 GeV from the distant and short GRB 090510. We find no evidence for the violation of Lorentz invariance, and place a lower limit of 1.2E_Planck on the scale of a linear energy dependence (or an inverse wavelength dependence), subject to reasonable assumptions about the emission (equivalently we have an upper limit of l_Planck/1.2 on the length scale of the effect). Our results disfavour quantum-gravity theories in which the quantum nature of space–time on a very small scale linearly alters the speed of light.

And that isn't all!  There is yet another interesting Fermi paper just out, The Fermi Haze: A Gamma-Ray Counterpart to the Microwave Haze.  This has implications for WIMP dark matter models which would explain the observation, though this is only a speculation, but it is exciting to speculate...

UPDATE: This video really nails what is going on here:

Goethe and Hemingway: Quantified

Photo by Martin C. Eisenloeffel 

Welcome to the digital Weimar. The theme: linking art and science. How does art influence science? How does science influence art? Beauty, elegance, simplicity? Lets ask Goethe, Goethe, the last great polymath!

The Perimeter Institute's Quarks to the Cosmos festival presents Quantifying Goethe. Now experience simultaneously the Penderecki string quartet's quantum computer inspired music and an excerpt from Milan Kundera's Immortality chapter 17:

Strolling down a road in the other world, Hemingway saw a young man approaching him from a distance; he was elegantly dressed and held himself remarkably erect. As this dandy came closer, Hemingway could discern a slight, raffish smile on his face. When they were separated by just a few steps, the young man slowed his walk, as if he wanted to give Hemingway a last opportunity to recognize him.
    "Johann!" Hemingway exclaimed in surprise.
    Goethe smiled with satisfaction; he was proud that he head succeeded in producing such an excellent dramatic effect. Let's not forget that he had long been active as a theatrical director and had a sense of showmanship. He then took his friend by the arm (interestingly, even though he was now younger than Hemingway, he still behaved with the indulgence of the elderly) and took him on a leisurely walk.
    "Johann," said Hemingway, "today you look like a god." His friend's good looks caused him sincere joy, and he laughed happily: "Where did you leave you slippers? And that green eye shade? "And after he stopped laughing, he said, "That's how you should come to eternal trial. To crush the judges not with arguments but with you beauty!"
    "You know, I didn't say one single word at the eternal trial. Out of contempt.  But I couldn't keep myself from going there and listening to the proceedings. Now I regret it."
    "What do you want? You were condemned to immortality for the sin of writing books.  You explained it to me yourself."
    Goethe shrugged and said with some pride, "Perhaps our books are immortal, in a certain sense. Perhaps." He paused and then added softly, with great emphasis, "But we aren't."
    "Quite the contrary,"  Hemingway protested bitterly.  "Our books will probably soon stop being read. All that will remain of your Faust will be that idiotic opera by Gounod.  And maybe also that line about the eternal feminine pulling us somewhere or other..."
    "Das Ewigweibliche zieht uns hinan," recited Goethe.
    "Right. But people will never stop prying into your life, down to the smallest details."
    "Haven't you realized yet, Ernest, that figures they talk about have nothing to do with  us?"
    "Don't tell me, Johann, that you bear no relation to the Goethe about whom everybody writes and talks. I admit that the image that remained behind you is not entirely identical to you. I admit that it distorts you quite a bit. Still, you are present in it."
    "No, I'm not," Goethe said very firmly. "And I'll tell you something else. I am not even present in my books. He who doesn't exist cannot be present."
    "That's too philosophical for me."
    "Forget for a moment that you're an American and exercise your brain: he who doesn't exist cannot be resent. Is that so complicated? The instant I died I vanished from everywhere, totally. I even vanished from my books. Those books exist in the world without me. Nobody will ever find me in them. Because you cannot find someone who not exist."
    "I'd like to agree with you," said Hemingway, "but explain this to me: if the image you've left behind has nothing to do with you, why did you lavish so much care on it while you were still alive? Why did you invite Eckermann to join you? Why did you start writing Poetry and Truth?"
    "Ernest, resign yourself to the idea that I was as foolish as you. That obsession with one's own image, that's man's fatal immaturity. It is so difficult to be indifferent to one's image. Such indifference is beyond human strength. One becomes capable of it only after death. And even then it doesn't happen at once, but only a long time after death. You still haven't reached that point. You're still not mature. And yet you've been death... how long, actually?"
    "Twenty-seven years," said Hemingway.
    "That's nothing. You'll have to wait at least another twenty or thirty years before you become fully aware that man is mortal and be able to draw all the consequences from that realization. It won't happen any sooner. Just shortly before I died I declared that I felt such creative power within me, it was impossible for it to disappear without a trace. And of course I believed that I would live in the image I left behind me. Yes, I was just like you. Even after death it was hard to me to accept the idea that I no longer existed. You know, it's really very peculiar. To be mortal is the most basic human experience, and yet man has never been able to accept it, grasp it, and behave accordingly. Man doesn't know how to mortal. And when he dies, he doesn't even know how to be dead."
    "And do you know how to be dead, Johann?: asked Hemingway, in order to lighten the gravity of the moment. "Do you really believe that the best way to be dead is to waste time chatting with me?"
    "Don't make a fool of yourself, Ernest," said Goethe. "You know perfectly well that at this moment we are but the frivolous fantasy of a novelist who lets us say things we would probably never say on our own. But to conclude. Have you noticed my appearance today?"
    "Didn't I tell you the moment I set eyes on you? You look like a god!"
    "This is how I looked when all Germany considered me a pitiless seducer," Goethe said with an almost grandiose air. Then, moved, he added, "I wanted you to take me with you into your future years in precisely this way."
    "Hemingway looked at Goethe with sudden, gentle indulgence: "And you, Johann, how long have you lived since your death?"
    "One hundred and fifty-six," Goethe answered with some embarrassment.
    "And you still haven't learned how to be dead?"
    "Goethe smiled. "I know, Ernest. I've been behaving differently from what I've been telling you just a moment ago. But I permitted myself this childish vanity, because today we are seeing each other for the last time," And then, slowly, as one who would speak no more, he said these words: "You see, I have come to the definite conclusion that the eternal trial is bullshit. I have decided to make use of my death at least and, if I can express it with such an imprecise term, to go to sleep. To enjoy the delights of total nonexistence, which my great enemy Novalis used to say has a bluish color."

The entire Perimeter institute performance of Quantifying Goethe is shown below. The video above is an excerpt from the 29th minute.

Other Worlds: Rare Astronomical Works

Image courtesy of the Harry Ransom Center at The University of Texas at Austin.

The Harry Ransom Center is a bastion of books. It is a research library located at the University of Texas at Austin; I used to work there and I must say it is a bibliophiles obsession. I remember that in the labyrinth of rare book stacks the fire alarms had signs posted saying something to the effect of, 'Warning: In case of fire the oxygen in this room will be removed' and below one of these warnings a page from the days of yore had scrawled, 'No one hears you scream in the stacks'. And they were right. There are so many books, so many rooms, and so many floors that I don't think anyone would hear you scream. But the authors in those books are a silent shout at an enduring literary, scientific, and artistic history.

The center is becoming something of a paragon in its field. And it is odd to ponder why do the archives of so many great writers end up in Texas? D. T. Max discusses the question in this article from the New Yorker. They also have a picture slide show on the tools of the trade.

Other Worlds: Rare Astronomical Works is a current exhibition showing at the center. They don't have an extensive web exhibition up for this collection (although they do have several other delightful online exhibits), but they do have a video discussing the collection and a nifty online preview which you may spin to visualize the Coronelli Celestial Globe. Their official blurb is below.

The Harry Ransom Center, a humanities research library and museum at The University of Texas at Austin, will present the exhibition "Other Worlds: Rare Astronomical Works," showcasing items from the center's science collection that survey some of the most important astronomical discoveries of the last 500 years.

Coinciding with the International Year of Astronomy, "Other Worlds" displays how the historical role of astronomy has come to influence the way the modern world is perceived.

With more than 40 rare editions of works by astronomers such as Johannes Kepler and Tycho Brahe, "Other Worlds" includes works by the individuals whose ideas revolutionized astronomical thought. From Nicolaus Copernicus's "De Revolutionibus," the first text to promote a heliocentric view of the solar system, to atlases of stars and constellations, the exhibition illustrates how early hypotheses laid the foundation for modern theories of the universe and its origins.

The exhibition also features items from the Ransom Center's papers of the Herschel family, a 19th-century English family of influential astronomers, including William Herschel, discoverer of the planet Uranus, and his sister Caroline Herschel, one of the first female astronomers. Highlights from the Herschel collection include the family's catalog of thousands of stars in the universe, William Herschel's 1836 account of Halley's Comet and a handmade astronomical device for locating heavenly bodies.

"Other Worlds" also examines the range of astronomy's influence on the broader culture, reflected in depictions of the moon and other worlds in literature, photography and popular works. From Jules Verne's novel "From the Earth to the Moon" to the 1923 moon illustration guide "Hutchinson's Splendour of the Heavens," the exhibition spans genres in revealing the breadth of astronomy's impact.

Read on...

Coronelli celestial globe, ca. 1688. Photo by Pete Smith. Image courtesy of
the Harry Ransom Center.

Smithsonian Air and Space Posters

The Smithsonian National Air and Space Museum has digitized their poster collection online. Above are some of my favorite picks and below a blurb about the posters.

Throughout their history, posters have been a significant means of mass communication, often with striking visual effect. Wendy Wick Reaves, the Smithsonian Portrait Gallery Curator of Prints and Drawings, comments that "sometimes a pictorial poster is a decorative masterpiece-something I can't walk by without a jolt of aesthetic pleasure. Another might strike me as extremely clever advertising … But collectively, these 'pictures of persuasion,' as we might call them, offer a wealth of art, history, design, and popular culture for us to understand. The poster is a familiar part of our world, and we intuitively understand its role as propaganda, promotion, announcement, or advertisement."

Reaves' observations are especially relevant for the impressive array of aviation posters in the National Air and Space Museum's 1300+ artifact collection. Quite possibly the largest publicly-held collection of its kind in the United States, the National Air and Space Museum's posters focus primarily on advertising for aviation-related products and activities. Among other areas, the collection includes 19th-century ballooning exhibition posters, early 20th-century airplane exhibition and meet posters, and twentieth-century airline advertisements.

The posters in the collection represent printing technologies that include original lithography, silkscreen, photolithography, and computer-generated imagery. The collection is significant both for its aesthetic value and because it is a unique representation of the cultural, commercial and military history of aviation. The collection represents an intense interest in flight, both public and private, during a significant period of its technological and social development.

Hip-Hop Physics

The Ising and Hubbard models are really clever physical approximations from statistical physics. The Wikipedia page on the Ising model is extensive and every physicist should preform the 1D solution at some point in their life, and for others just taking a look at these models and considering their application to the social sciences is worth considering. Anyways onto Hip-Hop Physics from the American Scientist (by Brian Hayes who also runs the bit-player) which discusses the challenges inherent in solving even these simple mathematical models (I first saw this link on 3QuarksDaily and have shamelessly reproduced it here, but good science writing must be propogated):

Mathematical models and computer simulations usually begin as aids to understanding, introduced when some aspect of natural science proves too knotty for direct analysis. Facing an intractable problem, we strip away all the messy details of the real world and build a toy universe, one simple enough that we can hope to master it. Often, though, even the dumbed-down model defies exact solution or accurate computation. Then the model itself becomes an object of scientific inquiry—a puzzle to be solved.
A good example is the Ising model in solid-state physics, which attempts to explain the nature of magnetism in materials such as iron. (I wrote about the Ising model in an earlier Computing Science column; see “The World in a Spin,” September–October 2000.) The Ising model glosses over all the intricacies of atomic structure, representing a magnet as a simple array of electron “spins” on a plain, gridlike lattice. Even in this abstract form, however, the model presents serious challenges. Only a two-dimensional version has been solved exactly; for the three- dimensional model, getting accurate results requires both algorithmic sophistication and major computer power.

Read on...

Space Exploration Missions

The image above is a link to a huge diagram showing space exploration missions. I have no idea how comprehensive of missions it is. I think the original source was National Geographic so it must be rather complete. Regardless the image is stunning in a visual design sense and it makes a good desktop background. Enjoy.

Wanted

A Dream

In a deserted place in Iran there is a not very tall stone tower that has neither door nor window. In the only room (with a dirt floor and shaped like a circle) there is a wooden table and a bench. In that circular cell, a man who looks like me is writing in letters I cannot understand a long poem about a man who in another circular cell is writing a poem about a man who in another circular cell . . . The process never ends and no one will be able to read what the prisoners write.

A Dream by Jorge Luis Borges (Translated, from the Spanish, by Suzanne Jill Levine.)

En un desierto lugar del Irán hay una no muy alta torre de piedra, sin puerta ni ventana. En la única habitación (cuyo piso es de tierra y que tiene la forma del círculo) hay una mesa de madera y un banco. En esa celda circular, un hombre que se parece a mí escribe en caracteres que no comprendo un largo poema sobre un hombre que en otra celda circular escribe un poema sobre un hombre que en otra celda circular . . . El proceso no tiene fin y nadie podrá leer lo que los prisioneros escriben.
Un Sueño por Jorge Luis Borges

Planck is Alive

Planck Status: Routine Operations (First All-Sky Survey)
Location: in orbit around L2

The Planck satellite after its successful launch a few months ago has first light! I am busy observing at APO (read waiting for the weather to clear) so I don't have time to write more, but I just wanted to drop this news as it breaks.

1/48-scale model of an F-18 aircraft

I stumbled upon Cabinet magazine recently. It is a quarterly print magazine of art and culture. The current issue No. 34 is about testing or sort of the intersection of culture and scientific testing. There is a great article available online (you will have to pick up a physical copy to read the other articles, but I did and it was worth it) about games of chance, but it was the cover image that really caught my attention:

This image shows a plastic 1/48-scale model of an F-18 aircraft inside the "Water Tunnel" more formally known as the NASA Dryden Flow Visualization Facility. Water is pumped through the tunnel in the direction of normal airflow over the aircraft; then, colored dyes are pumped through tubes with needle valves. The dyes flow back along the airframe and over the airfoils highlighting their aerodynamic characteristics. The aircraft can also be moved through its pitch axis to observe airflow disruptions while simulating actual flight at high angles of attack.

The Water Tunnel at NASA's Dryden Flight Research Center, Edwards, CA, became operational in 1983 when Dryden was a Flight Research Facility under the management of the Ames Research Center in Mountain View, CA. As a medium for visualizing fluid flow, water has played a significant role. Its use dates back to Leonardo da Vinci (1452-1519), the Renaissance Italian engineer, architect, painter, and sculptor. In more recent times, water tunnels have assisted the study of complex flows and flow-field interactions on aircraft shapes that generate strong vortex flows. Flow visualization in water tunnels assists in determining the strength of vortices, their location, and possible methods of controlling them.

The design of the Dryden Water Tunnel imitated that of the Northrop Corporation's tunnel in Hawthorne, CA. Called the Flow Visualization Facility, the Dryden tunnel was built to assist researchers in understanding the aerodynamics of aircraft configured in such a way that they create strong vortex flows, particularly at high angles of attack. The tunnel provides results that compare well with data from aircraft in actual flight in another fluid-air. Other uses of the tunnel have included study of how such flight hardware as antennas, probes, pylons, parachutes, and experimental fixtures affect airflow. The facility has also been helpful in finding the best locations for emitting smoke from flight vehicles for flow visualization.

Hubble's New Look

A servicing mission was planned for the 19-year-old Hubble Space Telescope years ago, but after the instrument command and data handling module failed the repair mission was postponed so that an even more comprehensive repair mission could be undertaken. Three months ago the space shuttle Atlantis launched and successfully repaired the telescope. The instruments on the telescope which were repaired or replaced include the Wide Field Camera 3, the Advanced Camera for Surveys, the Cosmic Origins Spectrograph, and the Space Telescope imaging Spectrograph. So NASA is patting its back right now on a job well done and releasing an entire gallery of press images for the publicity, but there are real promises for science to come.

My favorite image is that of Planetary Nebula NGC 6302 (which could easily be called the Butterfly Nebula, but the name is taken), but the comparison of Stephan's Quintet taken by Hubble to the image I took using the Harlan J. Smith Telescope at the McDonald observatory is laughable.