Scottish Scientists Slow down Light Particles - Photons

The speed of light is a limit, not a constant, that's what researchers in Glasgow, Scotland, say. A group of them just proved that light can be slowed down, permanently.

Scientists already knew light could be slowed temporarily. Photons change speeds as they pass through glass or water, but when they exit the other side and return to a vacuum (like outer space) they speed back up.

In a new experiment at the University of Glasgow, however, scientists were able to permanently manipulate light's speed by passing photons through a device that alters their structure. The device, created in collaboration with researchers at Heriot-Watt University in Edinburgh, is a filter of sorts that the scientists refer to as a mask.

"That mask looks a little bit like a bull's-eye target," researcher Miles Padgett told reporters. "And that mask patterns the light beam, and we show that it's the patterning of the light beam that slows it down.

"But once that pattern has been imposed, even now the light is no longer in the mask, it's just propagating in free space, the speed is still slow," Padgett added.

In other words, the beam of light is reorganized in a way that slows down each individual photon. When tested in a vacuum next to a regular light beam.

Photons that had been filtered through mask were milliseconds behind in a sprint to the end of the vacuum racetrack.

Researchers, whose latest work was published this week in the journal Science Express, say the findings prove the speed of light is not an absolute, more like a ceiling.

Miles Padgett

The work was carried out by a team from the University of Glasgow’s Optics Group, led by Professor Miles Padgett, working with theoretical physicists led by Stephen Barnett, in partnership with Professor Daniele Faccio from Heriot-Watt’s Institute of Photonics and Quantum Sciences.

Daniele Faccio

Professor Faccio said, “The speed of light is a universal constant and plays a central role in our understanding of the Universe and Einstein's theory of relativity."

"The exciting discovery here is that this speed is the true speed of light only for plane waves, that is waves that are perfectly flat."

"In everyday situations however, we interact with light that is not a plane wave but has some kind of structure on it."

"The presence of this structure (think of the light beam emitted from a laser pointer) forces the light to actually move slower."

"There are lots of technicalities involved in the actual experiments used to measure this slow-down, but the result is widely applicable. A very appropriate discovery for the 2015 international year of light".

Professor Padgett added, “It might seem surprising that light can be made to travel more slowly like this, but the effect has a solid theoretical foundation and we’re confident that our observations are correct.

“The results give us a new way to think about the properties of light and we’re keen to continue exploring the potential of this discovery in future applications."

"We expect that the effect will be applicable to any wave theory, so a similar slowing could well be created in sound waves, for example.”

More Information
Spatially structured photons that travel in free space slower than the speed of light - Science Magazine January 22 2015 - Science DOI: 10.1126/science.aaa3035

ESO VLT: Hosting unique intergalactic GPS instrument to map the stars

Artist's impression of the MOONS instrument. Credit: STFC

A €9M contract is announced today for Scottish engineers and designers to build a unique and powerful instrument that aims to tackle some of the most compelling astronomical puzzles, such as how stars and galaxies form and evolve, and probing the structure of our own Milky Way.

A project team from the Astronomy Technology Centre (ATC) in Edinburgh will lead this international project to develop and build MOONS for the European Southern Observatory's (ESO) Very Large Telescope (VLT) in northern Chile, already the world's most productive ground-based astronomical facility.

MOONS (Multi-Object Optical and Near-infrared Spectrograph) will allow astronomers to see obscured areas in the Milky Way at a distance of around 40,000 light years away, and enable them to create a 3D map of our galaxy.

This is difficult to do as the Earth is in the middle of the Milky Way's disc, so the process is like trying to map a forest of densely-packed trees from the inside.

Director of the ATC, Professor Gillian Wright, said "The team at ATC in Scotland have an opportunity with this project to enable all of us to understand why the Milky Way looks the way it does."

"This instrument will act as an intergalactic GPS to help us to navigate through the billions of stars in our galaxy and create a comprehensive map of its structure."

Conceived at the ATC, part of the Science and Technology Facilities Council (STFC), MOONS is scheduled to become operational by 2019.

Building such an ambitious and powerful new device, which will be about the size of a transit van, will take around 200 staff-years of effort, with the hardware alone costing €9M.

The full project will cost around €23M. The ATC will lead the Project Office managing the multinational consortium that will construct MOONS, and will also play a vital design role for key components and ensure the project's benefits extend throughout UK industry.

ESO's VLT platform. (Credit: ESO)

Like any spectrograph, MOONS will use the colour of light emitted by objects to reveal their chemical composition, mass, speed and other properties.

Breaking new ground by simultaneously observing 1000 objects using fibre-optic cables to feed their visible and infrared light into the instrument, it will survey large samples of objects far faster than any existing instrument and conduct surveys that would be virtually impossible using today's technologies.

Not surprisingly, the design will pose extraordinary technical demands. For example, each of the 1000-plus fibres will have to move into position very quickly, with great accuracy and without colliding with each other.

The ATC will develop the most innovative component, the individual motorised systems allowing each fibre to move rapidly into position; it will also develop the cryostat system (used to cool MOONS down to -170°C) vital to enabling the infrared observations needed to penetrate galactic and intergalactic dust clouds.

The University of Cambridge will take the credit for developing complex cameras capable of meeting the instrument's demanding performance requirements.

Partnerships with a range of UK equipment suppliers will also contribute across the project, helping the UK to further strengthen its cutting-edge scientific capabilities in the relevant fields.

Scottish Research: Milky Way Galaxy is smaller than believed

The Milky Way is smaller than astronomers previously thought, according to new research by Dr Jorge Penarrubia of Scotland's Edinburgh University.

For the first time, scientists have been able to precisely measure the mass of the galaxy that contains our solar system.

Researchers have found that the Milky Way is approximately half the weight of a neighbouring galaxy, Andromeda, which has a similar structure to our own.

The Milky Way and Andromeda are the two largest in a region of galaxies which astronomers call the Local Group.

Scientists say that Andromeda's extra weight must be present in the form of dark matter, a little-understood invisible substance which makes up most of the outer regions of galaxies.

They estimate that Andromeda contains twice as much dark matter as the Milky Way, causing it to be twice as heavy.

Researchers say their work should help them learn more about how the outer regions of galaxies are structured. Their findings also provide further evidence in support of a theory which suggests that the universe is expanding.

Although both galaxies appear to be of similar dimensions, until now scientists had been unable to prove which is larger.

We always suspected that Andromeda is more massive than the Milky Way, but weighing both galaxies simultaneously proved to be extremely challenging. 

Our study combined recent measurements of the relative motion between our galaxy and Andromeda with the largest catalogue of nearby galaxies ever compiled to make this possible. - Dr Jorge Peñarrubia, Edinburgh University, School of Physics and Astronomy.

Previous studies were only able to measure the mass enclosed within both galaxies' inner regions. In this new study, researchers were also able to work out the mass of invisible matter found in the outer regions of both galaxies, and reveal their total weights. They say 90 per cent of both galaxies' matter is invisible.

An image of the Andromeda galaxy, Messier 31.

Credit: Malyshchyts Viktar / Fotolia

A team of scientists led by the University of Edinburgh used recently published data on the known distances between galaxies, as well as their velocities, to calculate the total masses of Andromeda and the Milky Way.

Journal Reference: Jorge Peñarrubia, Yin-Zhe Ma, Matthew G. Walker, and Alan McConnachie. A dynamical model of the local cosmic expansion. Monthly Notices of the Royal Astronomical Society,, 2014; 443: 2204-2222 DOI: 10.1093/mnras/stu879

Scottish scientists use Backpacks to monitor personal air pollution

Scientists in Edinburgh are using hi-tech backpacks to study personal exposure to air pollution.

Air pollution is routinely measured by a network of urban monitors at fixed locations across Scotland.

But these are unable to provide a detailed picture of an individual's exposure throughout the day.

Scientists at the Centre for Ecology & Hydrology have provided volunteers with backpacks fitted with particle monitors and GPS satellite tracking technology.

Graph on laptop, showing David’s exposure to air pollution in Edinburgh

The volunteers wear the small backpacks throughout the day and sleep with them beside their beds at night.

The results are then analysed to assess exposure to tiny particles, mainly from combustion, known as particulate matter.

Doctors say there is a strong link between exposure to particulate matter and the risk of heart attack.

Dave Newby

Professor Dave Newby, of the University of Edinburgh and the British Heart Foundation, said: "We all think that when we breathe in air pollution, it must provoke pneumonia, or asthma or lung problems. But actually, it kills far more people from heart disease.

"What we've found is that the biggest trigger is the particulate matter that we breathe in. In the urban environment, the biggest contributor to that is diesel engines."

Dr Stefan Reis

The research investigating personal exposure to air pollution is being led by Dr Stefan Reis.

He believes the development of mobile air pollution monitoring equipment will be cheaper and more effective than investing in a larger network of fixed monitoring stations to cover whole cities.

He told reporters: "It's always easy to call for more monitoring but what we are trying to achieve is getting smarter monitoring.

"We're not trying to cover the whole countryside or city with many, very accurate monitors, which are very expensive, but using the combination of personal sensors, monitors on buses or trams, together with existing networks to get a much better picture of the actual exposure of people in the city."

The Scottish government has rejected criticism from environmentalists, who say ministers are failing in their duty to reduce air pollution levels.

Paul Wheelhouse

Environment minister Paul Wheelhouse said: "Working in partnership with local authorities, we've developed a network of monitoring sites, there's over 90 of them in Scotland, and we're using those to develop our strategy at a local level.

"In some cases, where they fail to meet the Scottish standard, which is a tough standard, they identify an air quality management area and that then triggers between the Scottish government and the local authority, who have a duty to deliver good air quality locally, to tackle that."

Roadside air pollution monitoring station

But Green MSP Patrick Harvie argues air pollution levels will remain too high until there is a fundamental change in transport policy in Scotland.

He said: "This locked-in pattern that we have to high transport demand is expensive, it's inefficient, it's unhealthy and it contributes to local and global pollution.

"Unless we see change in transport policy, we are not going to see change to the pollution levels in our cities and we'll be here in another 10 years listening to another environment minister saying much the same thing."

Scottish Cybraphon Sings - Video

Cybraphon Demo Song (The Balkan Bazaar) from Cybraphon on Vimeo.


Cybraphon is the latest project from Edinburgh-based artist collective FOUND (Ziggy Campbell, Simon Kirby and Tommy Perman).

Inspired by early 19th century mechanical bands such as the nickelodeon, Cybraphon is an interactive version of a mechanical band in a box. Consisting of a series of robotic instruments housed in a large display case, Cybraphon behaves like a real band.

Image conscious and emotional, the band’s performance is affected by online community opinion as it searches the web for reviews and comments about itself 24 hours a day.

This website documents the progress of the project as Cybraphon is comes to life at the Edinburgh Sculpture Workshop (ESW).

Cybraphon is funded by the Alt-w Production Award administered by New Media Scotland and will be unveiled at the Edinburgh Arts Festival on 5 August 2009 in InSpace Gallery.

Dusty Stellar Nurseries from the Dark Side of a Galaxy

The red colours in this image show the galaxy M66 as it appears at the sub-mm wavelength of 850 microns, while the white background shows the galaxy as it appears in visible light. 

Regions of cold dust that appear as dark streaks in the white image glow brightly in the red image. 

The center of the galaxy contains much more dust than is obvious from looking at the visible image and the sub-mm image also picks out an unusual compact cloud in the southern part of the galaxy that is a prime site for future star formation. Credit: VLT/ESO, JAC, G. Bendo.

One of the world's most powerful cameras, SCUBA-2 is producing its first detailed images of our neighbouring galaxies, revealing previously undetected vast pockets of star formation where the next generation of stars is being created.

The light from these stars is usually obscured by dust, but at the sub-millimetre wavelengths that the camera is designed for, these dust lanes actually glow brightly. The images are revealed in the week of the 25th anniversary of the James Clerk Maxwell Telescope, in Hawaii on which SCUBA-2 is mounted.

"This exquisite image from the galaxy M66 in the constellation Leo is exactly the promising start we were hoping for," said Dr. Stephen Serjeant, the team's co-leader from The Open University. "This is a wonderfully exciting taste of things to come."

When looking up at the Milky Way, an irregular pattern of dark regions obscures the light of the stars. The dark patches are caused by clouds of dust trailing through the spiral arms and blocking out the starlight that would otherwise reveal vast pockets of star formation, or stellar nurseries. These dark lanes are not exclusive to the Milky Way, but can be found in all spiral galaxies.

SCUBA-2, led by STFC's UK Astronomy Technology Centre in Edinburgh is the most powerful camera ever developed for observing light at sub-milimetre wavelengths, 1000 times longer than we can see with our eyes.

This makes it possible to detect stellar nurseries usually obscured by dust that are so remote the light they emit left them within the first billion years after the big bang.

University of Edinburgh astrophysicist Professor James Dunlop said: "These beautiful new images from SCUBA-2 show energy conservation in action, as the same dust which absorbs the blue optical light (obscuring the stars in the optical images) can be seen to re-emit at the much longer wavelengths accessible to SCUBA-2."

This image promises to be the first of many stunning results from the James Clerk Maxwell Telescope Nearby Galaxy Legacy Survey (NGLS). The main aim of the survey is to understand how the broader environment of a galaxy affects its gas and dust content.

For example, galaxies in dense clusters can lose their gas and dust through interactions with other galaxies in the cluster or simply by the head wind they feel while moving through the hot gas trapped inside the cluster.

The NGLS is an international collaboration led by astronomers from Canada, the Netherlands, and the United Kingdom which is using SCUBA-2 to observe 150 galaxies in the local universe.

The NGLS team has spent much of the last five years studying molecular hydrogen emission using another instrument on the James Clerk Maxwell Telescope.

"It is very exciting to now see the first results from the SCUBA-2 side of our programme starting to come in," says Professor Christine Wilson, the Principal Investigator from McMaster University in Canada.

"We have a unique sample of galaxies that we are studying and having SCUBA-2 data will let us measure their gas and dust content. Gas and dust usually go hand-in-hand in galaxies, but from time to time, you find a surprise."

STFC is the UK sponsor of astronomy and operates the Joint Astronomy Centre in Hawaii.

STFC: SCUBA-2 reveals wild youth of the Universe

A team of astronomers from the UK, Canada and the Netherlands has begun a revolutionary new study of cosmic star-formation history, looking back in time to when the Universe was still in its lively and somewhat unruly youth.

The consortium, co-led by University of Edinburgh astrophysicist Professor James Dunlop, is using SCUBA-2, the most powerful camera ever developed for observing light at ‘sub-mm’ wavelengths (light that has a wavelength 1000 times longer than we can see with our eyes).

Prof. Dunlop presented the first results from the survey at the UK National Astronomy Meeting on 27 March 2012.

The development of SCUBA-2 was led by STFC’s UK Astronomy Technology Centre in Edinburgh and the revolutionary camera was unveiled in December 2011 (link opens in a new window).

It is mounted on the world's largest sub-mm telescope, the 15-metre James Clerk Maxwell Telescope in Hawaii.

The new project, named the SCUBA-2 Cosmology Legacy Survey, will run for three years and will use the camera to provide the clearest view to date of dust-enshrouded star-forming galaxies.

These objects are so remote that the light we detect left them billions of years ago, so we see them as they looked in the distant past.

With SCUBA-2 astronomers are able to study objects that existed as far back as 13 billion years ago, within the first billion years after the Big Bang.

Because stars form inside clouds of gas and dust, much of the ultraviolet light from young galaxies is absorbed by this cosmic dust which is then heated to a few tens of degrees above absolute zero (-273 degrees Celsius).

The ‘warmed’ (but still rather ‘cool’) dust then emits the absorbed energy at far-infrared wavelengths, which is then further redshifted to longer sub-mm wavelengths en-route to the Earth by the expansion of the Universe.

The first image presented here is made using the SCUBA-2 camera at a wavelength of 450 microns.
(Credit: Jim Dunlop)

Detecting such emission is a challenge, both because Earth-based telescopes are warm and hence glow at sub-mm wavelengths and because water vapour in the atmosphere both absorbs and emits light in this waveband.

To get around the problems of the atmosphere, the latest sub-mm surveys have recently been conducted from space, using the Herschel Space Observatory.

However, the relatively small size (3.5-metre diameter) of Herschel’s telescope means that the images it produces cover large areas but are rather fuzzy.

The James Clerk Maxwell Telescope primary mirror is 20 times larger in area and can provide a much sharper view of the sub-mm sky.

Prof. Dunlop is delighted by these first deep SCUBA-2 images and looking forward to more results over the next few years: “Edinburgh scientists and engineers worked hard to construct this revolutionary new instrument and, together with our colleagues in Canada and the Netherlands, we’re now seeing the fruits of our efforts.

With SCUBA-2 we can study the most violently star-forming galaxies in the young Universe, and slowly but surely start to understand how the primitive cosmos evolved into the Universe we live in today.”

Edinburgh bright sparks solve our internet problems ... with the flick of a light switch

Edinburgh bright sparks solve our internet problems ... with the flick of a light switch - Herald Scotland

For what a world it would be if we could all access the internet not through clunky wireless routers and the millions of miles of spaghetti-like cables buried under our streets and fields, but through the golden rays of the electric light bulbs that are in every room in every one of our homes.

Scientists working at Edinburgh University have discovered a way of transmitting wireless data through lightbulbs, an invention that could revolutionise the way we receive the internet.

The discovery is called D-Light (data light) and uses the new light-emitting diode (LED) bulbs that are expected to replace the incandescent models in use. The traditional bulb is banned in parts of the EU due to its wasteful use of energy.

As well as revolutionising internet reception, it would put an end to the potentially harmful electromagnetic pollution emitted by wireless internet routers and has raised the prospect of ubiquitous wireless access, transmitted through streetlights.

The idea is so significant that a Nobel prize-winning physicist has named it among the 100 inventions likely to change everyday life in the next century.

Dr Harald Haas, reader in wireless communications at Edinburgh University, is leading the project.

He claimed the invention could soon be in use all over the world, bringing significant economic benefits to Scotland – and reaffirming the country’s position as one of the world’s leading nations when it comes to scientific innovation.

Dr Haas said: “Engineering and development have, in my opinion, been left out in this country for too long. Lord Mandelson has recently put forward his idea for the digital economy but it needs to be filled with life. This could be one pillar to that economy.

“It should be so cheap that it’s everywhere. Using the visible light spectrum, which comes for free, you can piggy-back existing wireless services on the back of lighting equipment. Power lines are there, which can transmit data, so all you need is a central modem, which would then distribute data into the lightbulbs and then to mobile devices in the home.”

The invention allows data to be transmitted through light, using flickering – imperceptible to the human eye – to send 100 megabits of data a second. That is twice as fast as current wireless routers and matches the speed of the broadband network which could get up to 100 megabits per second by 2017.

At that speed a file of an entire movie could be sent through a lightbulb in only a few minutes. But Dr Haas hopes to be able to send one gigabit a second, which is more than 10 times the speed the network can currently manage.

Wireless communication is a sector growing at an exponential rate, but the infrastructure is struggling to keep up

Artistic Endeavour and Schizophrenia: The Connection found in Edinburgh

Salvador Dali's mental disorders were also the key to his creativity. (Image: Philippe Halsman)

We are all familiar with the stereotype view of the tortured artist. Salvador Dali's various disorders and Sylvia Plath's depression, spring to mind. Now new research seems to show why: a genetic mutation linked to psychosis and schizophrenia also influences creativity.

The finding could help to explain why mutations that increase a person's risk of developing mental illnesses such as schizophrenia and bipolar syndrome have been preserved, even preferred, during human evolution, says Szabolcs Kéri, a researcher at Semmelweis University in Budapest, Hungary, who carried out the study.

Kéri examined a gene involved in brain development called neuregulin 1, which previous studies have linked to a slightly increased risk of schizophrenia. Moreover, a single DNA letter mutation that affects how much of the neuregulin 1 protein is made in the brain has been linked to psychosis, poor memory and sensitivity to criticism.

About 50 per cent of healthy Europeans have one copy of this mutation, while 15 per cent possess two copies.

Creative thinking

To determine how these variations affect creativity, Kéri genotyped 200 adults who responded to adverts, seeking creative and accomplished volunteers. He also gave the volunteers two tests of creative thinking, and devised an objective score of their creative achievements, such as filing a patent or writing a book.

People with two copies of the neuregulin 1 mutation – about 12 per cent of the study participants – tended to score notably higher on these measures of creativity, compared with other volunteers with one or no copy of the mutation. Those with one copy were also judged to be more creative, on average, than volunteers without the mutation. All told, the mutation explained between 3 and 8 per cent of the differences in creativity, Kéri says.

Exactly how neuregulin 1 affects creativity isn't clear. Volunteers with two copies of the mutation were no more likely than others to possess so-called schizotypal traits, such as paranoia, odd speech patterns and inappropriate emotions. This would suggest that the mutation's connection to mental illness does not entirely explain its link to creativity, Kéri says.

Dampening the brain

Rather, Kéri speculates that the mutation dampens a brain region that reins in mood and behaviour, called the prefrontal cortex. This change could unleash creative potential in some people and psychotic delusions in others.

Intelligence could be one factor that determines whether the neuregulin 1 mutation boosts creativity or contributes to psychosis. Kéri's volunteers tended to be smarter than average. In contrast, another study of families with a history of schizophrenia found that the same mutation was associated with lower intelligence and psychotic symptoms.

"My clinical experience is that high-IQ people with psychosis have more intellectual capacity to deal with psychotic experiences," Kéri says. "It's not enough to experience those feelings, you have to communicate them."

Intelligence's influence

Jeremy Hall, a geneticist at the University of Edinburgh in the UK who uncovered the link between the neuregulin 1 mutation and psychosis, agrees that the gene's effects are probably influenced by cognitive factors such as intelligence.

This doesn't mean that psychosis and creativity are the same, though. "There's always been this slightly romantic idea that madness and genius are the flipside to the same coin. How much is that true? Madness is often madness and doesn't have as much genetic association with intelligence," Hall says.

Bernard Crespi, a behavioural geneticist at Simon Fraser University in Burnaby, British Columbia, Canada, is holding his applause for now. "This is a very interesting study with remarkably strong results, though it must be replicated in an independent population before the results can be accepted with confidence," he says.