Features

It seems, early on its life, our Universe was a place of extremes.

That’s the conclusion scientists are drawing from new infrared observations of a very distant, unusually bright and massive elliptical galaxy.

This galaxy [in the white square above] was spotted 10 billion light years away, and gives us a glimpse of what the Universe looked like when it was only about one-quarter of its current age.

Measurements show that the galaxy is as large and equally dense as elliptical galaxies that can be found much closer to us. Coupled with recent observations by a different research team - which found a very compact and extremely dense elliptical galaxy in the early Universe - the findings deepen the puzzle over how ‘fully grown’ galaxies can exist alongside seemingly ‘immature’ compact galaxies in the young Universe.

‘What our observations show is that alongside these compact galaxies were other ellipticals that were anything up to 100 times less dense and between two and five times larger – essentially ‘fully grown’ – and much more like the ellipticals we see in the local Universe around us,’ explains Michele Cappellari of Oxford University’s Department of Physics, an author of a report of the research in The Astrophysical Journal Letters.

‘The mystery is how these two different extremes, ‘grown up’ and seemingly ‘immature’ ellipticals, co-existed so early on in the evolution of the Universe.’

Elliptical galaxies, which are regular in shape, can be over ten times as massive as spiral galaxies such as our own Milky Way and contain stars which formed over 10 billion years ago. One way of checking the density of such galaxies is to use the infrared spectrum they emit to measure the spread of the velocities of their stars, which has to balance the pull of gravity.

Measurements of a distant compact elliptical galaxy have shown that its stars were dispersing at a velocity of about 500 km per second, consistent with its size but unknown in local galaxies.

The new study, using the 8.3-m Japanese Subaru telescope in Hawaii, found a ‘fully grown’ elliptical with stars dispersing at a velocity of lower than 300 km per second, much more like similar galaxies close to us.

‘Our next step is to use the Subaru telescope to find the relative proportion of these two extremes, fully grown and compact ellipticals, and see how they fit in with the timeline of the evolution of the young Universe,’ Michele tells us. ‘Hopefully this will give us new insights into solving this cosmic puzzle.’

Dr Michele Cappellari is based at Oxford’s Department of Physics.

The research was conducted by an international team led by Masato Onodera, CEA/Saclay, France.

What with ash clouds and elections the Large Hadron Collider has been out of the headlines recently.

So I enjoyed this update from Paul Rincon at BBC News online who spoke to Tony Weidberg of Oxford University's Department of Physics about the LHC's ATLAS experiment.

ATLAS is looking for new discoveries in the head-on collisions of protons at very high energy inside the machine. Tony explains that within a few months it could be sensitive enough to probe the 1,000 gigaelectronvolt [GeV] mass scale where particles, such as W prime and Z prime bosons, are thought to exist.

Why do these funny-sounding particles matter?

Well, whilst we already know about their lighter cousins (normal w and z bosons are found at 100 GeV) finding these supersized particles could reveal some strange new physics and help us understand the forces that control our universe.

One possibility is that the 'lighter' bosons, which physicists describe as 'left-handed', could be one of a pair.

Tony tells BBC Online: 'We're into speculation here, but one possibility is that the Universe is really symmetric at high energies and that there are right-handed W bosons as well... For some reason, they happen to be much heavier than the left-handed W bosons we know.'

Of course symmetry is just one thing on the minds of LHC scientists.

As OxSciBlog previously reported Oxford's ATLAS team are exploring a range of phenomena with Caterina Doglioni amongst those looking to 'rediscover' the Standard Model, and assess how it fares in this new high-energy world, and Hugo Beauchemin leading the hunt for early evidence of new physics beyond the Standard Model.

Meanwhile Oxford's Cigdem Issever is planning to use ATLAS to find mysterious (but surprisingly non-threatening) 'mini' black holes.

Exciting stuff. The one downside is that, according to Tony, it's likely to be 2011 at the earliest before researchers can start looking for the biggest piece missing from the physics jigsaw: the Higgs boson.

With new fossil fuel power stations being built every week, and the idea of burying CO2 [carbon sequestration] regarded by many scientists as unproven or even unworkable, coming up with an alternative solution to what to do with CO2 is more pressing than ever.

What chemists dream about is turning CO2 from a dangerous greenhouse gas into a useful fuel. But to make this dream a reality will take more than clever chemistry.

That’s why a team at Oxford University is bringing together expertise in chemistry, materials science, engineering and the social sciences to tackle one of the grand challenges of the 21st Century.

A simple recipe
Peter Edwards of Oxford University’s Department of Chemistry, one of the leaders of this team, starts by telling me about the simplest recipe for turning CO2 into fuel: just add hydrogen, then inject some energy from sunlight and you can produce methanol – a versatile feedstock that can be made into all kinds of fuels.

It’s a nice idea, but there’s a big problem. ‘Where do you get the hydrogen from?’ Peter asks. In fact, he explains, 98 per cent of the world’s hydrogen comes from another fossil fuel, methane: and not only is this a finite resource but turning methane into hydrogen takes additional energy and emits more CO2.

'Back in the 1990s chemists had a thought: what if we could bypass hydrogen and make methane and CO2 react to produce methanol,’ he tells me, an idea given a further green boost by the growing resources of sustainable biomethane, especially in India and China.

The new recipe would see this biomethane added to the CO2 that otherwise would be sent up the power station chimney and would harness the existing heat of this CO2-rich ‘flue gas’ to help make the reaction more energy-efficient.

‘It’s all about the energy balance,’ Peter says, ‘if we can use natural gas or biomethane in this process rather than just burning it we’re winning in terms of the energy we get out and the emissions we eliminate.' Now we’re cooking!

Mix with realism
Yet while this sort of chemical recipe was already shown in the 90s to work with a ‘pure’ gas, the sort of emissions that come from a fossil fuel power station are typically full of impurities.

‘Real flue gas is made up of nitrogen oxide (NOx), nitrogen, and oxygen as well as CO2,’ Peter tells me. Up until now dealing with this sort of realistically ‘dirty’ chemical cocktail of gases has been an almost impossible hurdle – especially as scrubbing out the impurities would use up more energy and generate more CO2 emissions.

And if that wasn’t bad enough NOx is a poisonous pollutant that it takes a lot of effort to remove.

Yet the Oxford team - Peter, Tiancun Xiao and Zheng Jiang (the first-ever John Houghton Fellow at Oxford) and colleagues - believe the key to making their CO2-into-fuel dreams a reality lies in new catalyst technology and a different way of thinking.

Instead of getting rid of the NOx the team believe they can use it as a catalyst to help power the reaction. They also cite the fact that the latest technology makes it possible to work with the sort of ‘dirty’ nitrogen-rich gas mix produced in a power station.

To be able to turn the CO2 in this mixed gas and methane into methanol in a power station without an accumulation of carbon causing everything to grind to a halt will take a new generation of nanoscale-structured magnetic catalysts.

Because such catalysts, based on metallic compounds like cobalt oxide, are magnetic they can be moved around by strong magnetic fields, agitating or ‘stirring’ them to ensure that the reaction is more efficient and doesn’t snuff itself out. It’s a novel approach that will require new research in materials science, chemistry and physics to work.

A good result
In the end though, even overcoming these challenges will come to nothing if the new approach isn’t economically viable and environmentally beneficial.

‘There are a lot of broader questions we need answers to: such as, how much natural gas or biomethane is there in the world? And can our solution have a real impact on overall carbon emissions?’ Peter tells me.

But, the team feel, this is where Oxford has an advantage calling on the expertise of the Department of Engineering Science, Begbroke Science Park, the Smith School of Enterprise and the Environment, and Rutherford Appleton Laboratory, as well as partners in the UK and China.

The Oxford team believe that by working on the whole challenge – not just the scientific or technological aspects – they can help to crack one of the world’s biggest and most intractable problems: how to make the CO2 we produce work for us and the planet.

A field in Chilbolton, Hampshire, could help unlock the secrets of peculiar rotating neutron stars known as pulsars.

It's here that an international team, including Oxford University scientists, are building an array that, linked up with stations in the Netherlands, Germany, and France will form LOFAR, one of the world's most powerful radio telescopes.

I asked LOFAR scientist Aris Karastergiou of Oxford's Department of Physics about the new telescope, the search for pulsars, and how games console hardware could help decode their enigmatic signals...

OxSciBlog: What makes pulsars so challenging to study?
Aris Karastergiou: In a sense it is amazing that we can study pulsars at all, as they are compact objects around 10-20 km in diameter. However, they emit very bright beams of light (in the radio frequencies) from their two magnetic poles, which sweep through space as the pulsar rotates.

If Earth happens to be in the path of these sweeping beams of a pulsar, we can point a radio telescope towards it and collect this light. Even then, however, the fact that the most scientifically interesting pulsars rotate over 100 times a second means that observations require not only high sensitivity but also very fast recorders, capable of sampling the incoming light at extremely short intervals.

The fact that pulsar light travels through the Galaxy before reaching us adds further challenges to pulsar studies, as radio waves interact with electrons in the medium between the stars.

OSB: What is LOFAR and how can it help with these studies?
AK: LOFAR (the Low Frequency Array) is a brand new telescope, made up of a large number of receiving elements organised in so-called stations. The core of this telescope is located in the Netherlands, while outer stations are located in Germany, France, the UK and elsewhere. Unlike other radio telescopes, LOFAR is not made up of parabolic reflectors (like satellite dishes), but of little radio antennas.

To point the telescope at a star in the sky, we electronically combine the signals from these antennas with a certain set of time delays LOFAR is a very sensitive telescope and we expect to discover a large number of new pulsars by surveying the northern sky. Compared to the existing giant radio telescopes, pulsars are brighter at LOFAR radio frequencies.

Observing at low frequencies will give us better understanding of the radio emission mechanism, and also shed light on the physical processes associated with the propagation of pulsar light through our Galaxy.

OSB: What difference will the new Chilbolton facility make?
AK: Each of the international LOFAR stations, including Chilbolton, contributes to LOFAR by increasing the capability to tell apart objects in the sky that appear very near to each other. If we imagine that LOFAR can take photographs of the sky, the most distant stations are necessary to reduce the pixel size and make images of greater detail.

On the other hand, the international LOFAR stations are very sensitive telescopes in their own right and can be used independently from LOFAR. They can observe large fields in the sky with large sensitivity and very fast sampling of the incoming radiation, making them very useful instruments for searches of bursty signals like giant radio pulses from pulsars.

We are enhancing the LOFAR station at Chilbolton to take full advantage of these capabilities, and we aim to transform it into a fantastic instrument of discovery.

OSB: How does the sort of hardware found in games consoles help you analyse signals?
AK: Modern games consoles use very powerful graphics processors to deliver stunning images and animation. The secret behind this lies in the enormous computing power of these processors at performing certain simple calculations in parallel. When searching for bright, short duration radio pulses of astronomical origin, we need to counter the effects of propagation of light through the Galaxy. This process involves a simple, repetitive algorithm that can be easily run in parallel on graphics processors.

We are currently building a computer cluster based on graphics processing units, which will be capable of performing a real-time search for bright, short duration astrophysical radio pulses in the data from the Chilbolton station.

Dr Aris Karastergiou is based at Oxford University's Department of Physics where he is a Leverhulme Early Career Fellow.

To help mark the centenary of Dorothy Hodgkin's birth a special play will be performed next week at Oxford University's Lady Margaret Hall.

The play, 'Hidden Glory: Dorothy Hodgkin in her own words', is a one-woman show starring Miranda Cook and written by Georgina Ferry, Writer in Residence at OUMNH and Hodgkin's biographer. I asked Georgina about Hodgkin, her achievements and bringing an Oxford legend to life:

OxSciBlog: Why is Dorothy Hodgkin such an important figure?
Georgina Ferry: Dorothy Hodgkin is the only British woman to have won a science Nobel prize. Only 15 women have ever won the prize for physics, chemistry or medicine. By any standards that makes her exceptional. Her significance as a scientist lies in her great skill in pioneering the technique of X-ray crystallography to study the three-dimensional arrangement of atoms in biological molecules. Today, using modern equipment that is many times more powerful, fast and accurate than was available in her time, studies of molecular structure underpin much of biomedical science.

OSB: What were her key achievements at Oxford?
GF: For the first two decades of her career at Oxford, Dorothy's X-ray lab was a basement in the corner of the University Museum of Natural History. There she resolved a debate between the organic chemists about the structure of penicillin, a discovery that contributed to the later development of other antibiotics. She went on to solve the structure of Vitamin B12, which prevents pernicious anaemia. Later she moved with her group to laboratories elsewhere in Oxford's Science Area, and completed her life's work - solving the structure of the protein insulin, which controls sugar in the bloodstream - in 1969.

OSB: Why did you decide to write a play about her?
GF: The Oxford University Museum of Natural History was planning to celebrate Dorothy's centenary this year by unveiling a bust of her in its court, alongside the statues of Newton, Darwin, Galileo and all the other great men of science. I thought it would make the evening more of an event if there were some kind of performance to accompany the unveiling, and that a play with Dorothy as the central character would bring her to life as nothing else could. I'm thrilled that the Museum, with help from the EPA Cephalosporin Fund and Diamond Light Source, decided to support the project.

OSB: What was the most difficult aspect of trying to tell her story?
GF: I wrote Dorothy's biography some years ago, which ran to some 400 pages (and could have been twice as long if I had used all the material available). But I knew that a one-woman show could not be longer than about 40 minutes. So the challenge was to select what to include, making sure there was enough to get across her character and her passion for solving scientific problems, but not so much that people would get bogged down in the detail.

OSB: What lessons can today's scientists learn from her life?
GF: Dorothy grew up believing that it was important to try and make a difference, whatever your chosen field. She was extremely determined without ever being aggressive; she was very good at finding the right people to ask for help, and was never shy about doing it; she was always supportive to her junior colleagues but expected them to stand on their own two feet. She was never motivated by competition with others, only by the challenge of solving nature's secrets.

'Hidden Glory: Dorothy Hodgkin in her own words'  will be performed at the Simpkins Lee Theatre, Lady Margaret Hall on Thursday 13 May at 7:30pm. Tickets are available here.