Features

Could the problem of global warming be solved simply by making fossil fuels more expensive?

Writing in The Guardian Ashley Seagar reports that as the price of oil goes through the roof solar power is seen as increasingly attractive. This is especially so in Germany where feed-in tariffs oblige utilities to buy in renewable energy at above the market rate.

It poses some interesting questions about whether economic or technological efficiencies are actually slowing the spread of renewables. As I've mentioned before Oxford researchers are amongst those looking at how to improve energy generation from solar power.

Yet, whilst we can expect improvements in solar power (and other renewables), as was pointed out at a recent debate on energy at Oxford electricity is only part of the story. Over half of the energy we use is expended on heating space and water - something the electricity supplied by solar cells would be particularly ill-suited to.

Are we ready and willing to rip out all our gas boilers and replace them with inefficient electric heating? Can we afford the trillions needed to transform our energy infrastructure from a centralised model in which energy flows out to one in which a large portion is drawn in from here, there and everywhere?

There's another sting in the tale for people who say renewables are a 'magic bullet' for our energy woes. As the price of oil rises so nuclear energy, just like solar and wind, will start to seem more attractive too...

What makes galaxies stop producing stars? Contrary to what you might think galaxies don't just run out of star-forming gas, there has to be something that's dispersing the gas or there'd be many more stars in the sky.

Scientists believe two mechanisms play a role in 'quenching' star formation: exploding supernovae and Active Galactic Nuclei (AGNs) - the stormy centres of galaxies powered by supermassive black holes.

At a recent AAS meeting, Sugata Kaviraj of Oxford's Department of Physics presented the first observations showing the role of AGNs. What these observations show is that AGNs take over from exploding supernovae as the main mechanism by which gas is dispersed as galaxies reach the critical size of 10 billion times the mass of the Sun.

'Our models of galaxies are all based on the notion that Active Galactic Nuclei are involved in ‘snuffing out’ – quenching – star formation in galaxies which are too large for mechanisms based on supernovae to explain,' Sugata tells us.

'Astronomers believe that the jets produced by Active Galactic Nuclei are powerful enough to ‘blow away’ star-forming gas from even the largest galaxies but up until now we have not had the observations to back this up.'

'Our observations using ultraviolet light show, for the first time, the relationship between the mass of a galaxy and whether supernovae or Active Galactic Nuclei play a dominant role in quenching star formation.'

Quantifying the role that AGNs play in quenching is of prime importance to astronomers and astrophysicists as it would enable them to calibrate their models of galaxies.

The observations used in the study were of nearby galaxies, the challenge now is to widen the scope of the work to include a representative sample of galaxies.

If you’re as absent-minded as I am, then it may be of comfort that Oxford researchers have shed some light on how memory is encoded in the brain.

All the information we take in, store, and then recall is somehow held in a complicated net of connections between neurons in the brain.

‘We know a lot about the hardware the brain uses to store memories and information – the different types of cells and how they are connected,’ explains Ole Paulsen of the Department of Physiology, Anatomy and Genetics. ‘But we have very little insight into the software – the programs the brain uses and the way its code works.’

Memories appear to be written into patterns of activity across our complex neural networks. Some connections between nerve cells are strengthened while others are weakened. Confusingly, both strengthening and weakening require the same molecule to operate. ‘This had been quite a conundrum,’ Ole says. ‘How does one molecule lead to both behaviours?’

Ole Paulsen and Antonio Rodriguez-Moreno, now in Spain at the Universidad Pablo de Olavide in Seville, have now solved this memory puzzle. Their results are published in Nature Neuroscience.

The molecules that manage the strengthening and weakening of nerve connections are called NMDA receptors. A connection between neurons works in only one way, so that there will be a ‘sender’ neuron and a ‘receiver’ neuron. Both have NMDA receptors but which receptors are active determines the result. If they are active on the receiver side, the connection will be strengthened and if they are active on the sender side, the connection will be weakened.

The researchers studied one specific type of connection in the brain, but they hope the solution to this particular puzzle will hold more widely.

‘If this is true more generally, then it is a fundamental result that will change the way we look at how memory is stored,” Ole says.

I can't resist highlighting this National Geographic article about desalination and the Middle East.

The Middle East, as we know, is short of fresh water but awash with salt water lakes and seas. The obvious solution is to build desalination plants to turn salt water into fresh water: this is exactly what Israel is doing with five state-of-the-art plants on the way.

Yet, the article suggests, whilst this approach may provide a short-term solution to one problem it may open up a watery Pandora's Box of others, here are a few examples:

Energy: Desalination plants use massive amounts of energy 24/7. With the region's present power infrastructure this energy will surely come from burning large amounts of fossil fuel. More carbon into the atmosphere speeds up climate change and makes drought situations worse.

Purity: The water produced may be 'too pure' with high boron levels that could be harmful to wildlife and reduced calcium and carbonate concentrations making it acidic enough to damage pipes.

Waste: Finding somewhere to dump super-salty, chemical-heavy waste water is also an issue (do we want another Dead Sea?).

Security: Desalination plants would become a major terrorist target: one expert estimates six or seven Hezbollah rockets could knock out the entire water supply system.

Could the downsides of these plants perhaps be mitigated by research into salt-tolerant cropsor more-efficient solar power? Let's hope so because, as one researcher comments: 'At the end of the day, water is life... if this is the only alternative and it can help us to avoid future conflicts, we will go for it.'

Spare a thought for Luna 5: it was on this day in 1965 that it attempted a 'soft' landing on the Moon but, due to a combination of gyroscope failure and human error, smashed into the surface.

It languishes in that limbo reserved for journeyman space missions between Luna 2, the first spacecraft to impact on another planet, and Luna 9, the first craft to make a controlled 'soft' landing on another world.

Luna 2 discovered that the Moon has no magnetic field. Luna 9 sent back three panoramic images of the lunar surface. Luna 5, like so many of its brethren into which so much technical know-how, energy, money and national pride was invested, just plain crashed. 

The Planetary Society give a full roll-call of successful and failed lunar missions but this is history still being written. As Oxford's own Chris Lintott (he of Galaxy Zoo fame) reported in a recent Sky at Night NASA's LCROSS craft will be sent hurtling into a crater near the lunar South Pole in 2009. A follow-up satellite will fly through the plume of ejected material to examine lunar soil and, significantly, look for water ice.

The results from LCROSS could help inform the efforts of NASA's LRO, which will be carrying a 'water diviner' instrument developed with the help of Fred Taylor and colleagues at Oxford's Department of Physics. The hope is that LCROSS's smashing exit will lead to scientific excitement not frustration.