By Hamish Johnston

Physicists were buzzing last month when scientists at the OPERA experiment in Italy hinted that neutrinos may move faster than the speed of light. If you missed all the excitement, the experiment measured the time it takes the particles to travel 730 km from CERN in Switzerland to Gran Sasso in Italy – and came up with a relativity-defying result.

Although there was much coverage of the “Was Einstein wrong?” sort in the popular media, I suspect that most physicists were quietly thinking “there must be something wrong with the experiment”. Others have been more vocal, with nuclear-physicist-turned-TV-presenter Jim Al-Khalili famously declaring that he will eat his boxer shorts if it turns out to be true.

Well, it looks like Jim won’t be tucking into his briefs any time soon because new data from OPERA’s sister experiment ICARUS have failed to yield any evidence for superluminal neutrinos. More precisely, ICARUS has shown that neutrinos travelling from CERN to Gran Sasso do not emit electron–positron pairs. Emission of such pairs is expected if the neutrinos travel faster than the speed of light, according to a preprint published recently by Andrew Cohen and Sheldon Glashow.

The emission of electron–positron pairs would have a noticeable effect on the energy distribution of neutrinos arriving at both OPERA and ICARUS, but now neither experiment has seen evidence of it.

OPERA’s superluminal result is based on the time it took for neutrinos to travel the 730 km – and now this speed measurement contradicts both the OPERA and ICARUS energy-distribution measurements.

I should point out that the Cohen–Glashow paper has yet to pass peer review (as far as I can tell). However, the preprint seems to meet with the approval of physicists who have blogged about it – and the ICARUS collaboration repeatedly uses the word “must” to describe the effect. And the fact that one of the authors is a Nobel laureate must give it additional kudos.

If you haven’t yet had your fill of superluminal neutrinos, the BBC will be airing a television programme on that very subject tonight. It will be hosted by the mathematician Marcus du Sautoy and you can find more details here.

UPDATE: The Cohen-Glashow paper has been accepted for publication in Physical Review Letters.

By Hamish Johnston

If you happened to be listening to BBC Radio 4 last night, you would have heard interviews with two famous American physicists. First up was Lawrence Krauss of Arizona State University, who is in London to give a lecture on Sunday about our relationship with the cosmos.

Krauss chatted with Quentin Cooper – host of Radio 4’s Material World science programme – about physics in the news, including dark energy, superluminal neutrinos and quasicrystals. You can listen to the programme here and Krauss appears after about 15 minutes.

Next up was cosmologist Lisa Randall (right) of Harvard University, who spoke with Radio 4’s Andrew Marr on his Start the Week programme – which this week was entitled “God and science” and also featured Richard Dawkins and the Chief Rabbi of England, Jonathan Sacks.

Dawkins kicked off with a discussion of his new book entitled The Magic of Reality: How We Know What’s Really True, which aims to show children and their families that the myths surrounding phenomena such as earthquakes and rainbows pale in comparison with the magic and wonder of science. Particularly interesting was Dawkins’ argument that space aliens must have eyes.

Randall speaks about her latest book Knocking on Heaven’s Door about 25 minutes into the programme, which you can listen to here. Earlier this year, she also spoke to our very own Michael Banks, and you can listen to that interview here.

Physics World podcasters. Left to right: Margaret Harris, James Dacey, Matin Durrani

By James Dacey

Followers of this blog may remember that a little over a month ago, I wrote an entry about how I had just been in the studio with my colleagues, Matin and Margaret, to record a special podcast about physics books. The theme of the podcast – our first ever – was “women in science” because all the books that we discussed were in some way connected to this theme. Well, after various discussions and good chunk of time spent in the editing suite, the programme is finally available to listen to online. You can also subscribe to our podcast service.

In the show, we discuss the following titles:

The Madame Curie Complex by Julie Des Jardins;
Discoverers of the Universe: William and Caroline Herschel by Michael Hoskin;
Science Secrets: the Truth About Darwin’s Finches, Einstein’s Wife and Other Myths by Alberto Martinez; and
Soft Matter: the Stuff that Dreams are Made Of by Roberto Piazza

In our next podcast, to be released in December, we will be discussing a selection of our favourite books reviewed in 2011, and announcing Physics World’s top 10 books of the year. In the meantime, you can continue to read book reviews each month in Physics World and on physicsworld.com.

By Matin Durrani

The guys who in 2008 came up with the annoyingly catchy “There’s no-one as Irish as Barack O’Bama” – more than a million hits on YouTube and counting – have re-recorded their song with new lyrics describing the latest mystery in particle physics.

Jumping on the huge interest in claims that neutrinos may travel faster than light, the musicians, known as the Corrigan Brothers and featuring someone called Pete Creighton, have called their new version simply “The neutrino song”.

The song’s not bad if cheesy synths and breezy pop are your thing, although it does that awful thing of going up a key near the end, which is a pet hate of mine.

But as I’ve learned to expect from a string of recent physics-meets-pop disasters, it’s the lyrics that will make your toes curl up.

I won’t spoil the lyrics by reprinting them here in full except to warn you of what is possibly the worst rhyme ever in the history of physics:

Now physics for ever may not be the same
And boffins are gonna be driven insane
If light’s not the fastest
What can this mean-o
And is something faster than the neutrino.

By James Dacey

As you may have just read in Tushna Commissariat’s account, on Monday and Tuesday scientists gathered at the Royal Society’s headquarters in London for a meeting about the Earth‘s climate history. One of the speakers at the event was James Hansen, a highly respected US space scientist, who is also well known for his advocacy of action to limit the impacts of climate change. In his talk, Hansen argued that – based on recent observational data – rapid reduction of fossil fuel consumption is essential if we are to avoid environmental catastrophe.

Following his talk, Hansen was asked the inevitable question of whether he saw any conflict of interest in his taking a transatlantic flight to deliver a lecture on the importance of cutting greenhouse gas emissions. His response was to say that at this stage it is already too late for this sort of minor sacrifice to make a significant difference, and that the more important thing is to communicate the message that urgent government action required. Hansen argued that the key to avoiding further rapid warming is for policy makers to establish high taxes on carbon emissions, which would act as an incentive for the development of green energy technologies.

But we want to know your opinion on this in relation to your professional life. Would you consider not attending a conference because it would involve a flight?

Yes. I would not attend, even if it could hurt my career.

No. My sacrifice would have no useful impact.

Possibly. I try to significantly limit my air travel.

I would take another means of transport, even if it drastically increased my travel time.

Please have your say by visiting our Facebook page and taking part in this week’s poll. And feel free to post a comment on the poll to explain your answer.

In last week’s Facebook poll we looked at the issue of financing large-scale science projects such as CERN’s Large Hadron Collider or the ITER project – the world’s largest experimental tokamak nuclear-fusion reactor, under construction in the south of France. We asked whether, in general, you think that “big science” facilities are value for money? 49% of respondents answered that yes they are worth the money, with just 3% answering no. The remaining 48% selected the measured option of “depends on the project”.

Craig Levin, one of our Facebook followers based in Chicago, Illinois, who voted yes, believes that funding agencies must look beyond the scientific goals of a project when making decisions. He commented that “one also has to take into account the return on investment and economic impact that these programmes can have on the economy, not just the scientific discoveries”. Marios Barlas, a follower based in Patrai, Greece, who also voted yes, takes a more Promethean view of science, commenting that “science never goes to waste. Be it theoretical or applied medical or humanitarian. There is always something to gain even out of utter failure.”

NASA’s Dr James Hansen (Courtesy: Greenpeace)

By Tushna Commissariat

This Tuesday I was in London meeting some exciting and important people in science. While you will have to wait until tomorrow to find out who I met with in the morning, in the afternoon I went along to the closing lecture at Royal Society’s paleoclimate conference Warm Climates of the Past – a Lesson for the Future?. The lecture was given by Dr James Hansen – the head of the NASA Goddard Institute for Space Studies who has been very vocal on the subject of climate change since the 1980s.

In “Earth’s climate history: lessons for the future” Hansen spoke about how observations of past climates coupled with current-day observations suggest that hard-hitting and immediate measures need to be put in place to avoid further global destruction. Rapid reductions in the use of fossil fuels are the best way to do so, he argued.

Hansen began his talk by saying that our basic understanding of the Earth’s paleoclimate history should depend more on global “real-world” geological observations, rather than climate models and theories. He feels that the Earth’s history provides the information that is necessary to better understand climate change today and that researching “climate sensitivity” at any given point depends on the timescale taken into consideration and the “climate state” at that given time.

Hansen went on to say that when some generally “intelligent people” say that the Earth has been a lot colder or warmer in the past, he is quick to point out that he doesn’t think that the global mean temperature was ever more than a degree higher, as far back as the last glacial period.

He categorized the three main factors affecting the global climate over the past 65 million years and presented the amount of warming change they would cause in Watts/m²:

*external effects (solar irradiance): +1 W/m²

*surface effects (continental location – geological changes): ~1 W/m²

*atmosphere (CO₂ change): >10 W/m²

He pointed out that the natural change in CO₂ has been steady at about 0.0001 ppm/year, whereas the human-generated rate today is at about 2 ppm/year. He also showed that the sea level has been rising at about 3 m per millennium, as compared with the near-constant level it has maintained for the past 6000–7000 years. His hard-hitting statement that “Humans could produce ‘a different planet’” makes it clear that he feels very strong measures need to be put in place to preserve the planet as we know it.

His main suggestion to achieve a more stable climate was a drastic cut in the use of fossil fuels worldwide, by levying high taxes on their use. “We cannot burn all the fossil fuels and yet our governments go along with that,” he said. “A solution has to be a gradually rising carbon tax.” He went on to explain that such a tax would mean that fossil fuels derived from tar sands, for example, would almost immediately stop as it would not make economic sense and that coal would follow soon after. He also feels that such a tax would go a long way toward making clean fuel sources the norm. “Rapid reduction of fossil-fuel emissions is required to succeed in preserving a planet resembling the one that civilization developed,” he said.

On a similar note, a recent Physics World opinion piece, titled “How big is your footprint?” and written by astrophysicist Phil Marshall of the University of Oxford, talks about how physicists carry the responsibility to reduce their own carbon footprints. These can be considerable when you consider the amount of energy that is required to run physics facilities or fly across the Atlantic frequently for conferences. For example, he points to CERN’s Large Hadron Collider energy bill – estimated at about €10m per year – comparable to that of all the households in the region around Geneva. He estimates that US astronomers use an additional 130 kWh per day more than the average citizen.

Marshall also talks about a workshop in Lund, Sweden, this week, where researchers are discussing energy for sustainable science to identify ways to do large-scale physics research with a reliable, affordable and sustainable energy supply that is “carbon neutral”. To read about that and maybe take a look the wiki Marshall runs for green-minded astronomers, take a look here.