Gareth Mitchell: Happy New Year and welcome to this the January edition of our Imperial College podcast. And I’m Gareth Mitchell of our Science Communication Group here at Imperial and I present Digital Planet on the BBC. Hello. And as for this podcast, well there’s lots for you this month including the Imperial scientist with an Earth shattering, well ice shattering, critique of a popularly held theory about the planet’s early history. That’s in just a moment. And also apart from some very opinionated staff what does the College have to offer postgraduates.

Voice 1: We are offering some of the best research teams in Great Britain in control and signal processing in micro-engineering and microsystems in electronics, intelligent and interactive networks.

Voice 2: It’s in London. Best city in the world. Lots to offer. Lots of experiences. And obviously one of the best universities in the world.

GM: I’ll be at the open day where the College tries selling itself to prospective students. And also this month, happy New Year and happy new job to one of our physics professors. A word with the new head of physics Joanna Haigh. And quite a promotion it is to in a field that’s often thought of as a boy’s subject. So does she agree?

Professor Joanna Haigh: I’m lucky enough. I’ve had a splendid career. I’ve really enjoyed myself and I haven’t, I don’t think, been subject to much discrimination or anything like that. But the sad state of affairs is that 18 year old or perhaps 16 year old girls don’t want to do physics.

GM: And the link between diabetes and abnormal sleep patterns. That’s just one of the stories in this month’s news roundup. It’s all coming up in this edition of our Imperial College podcast.

Professor Philip Allen on why 'Snowball Earth' theory should be thrown out

First though, millions of years ago there was an ice age so severe that the entire planet froze from pole to pole. Sounds a bit outlandish? Well, one of our scientists certainly thinks so. And in a journal article recently published he’s not holding back in criticising the so-called Snowball Earth hypothesis. It’s a fairly recent idea but it has become a popular notion and proponents of Snowball Earth say it’s backed up with good science.

But Professor Philip Allen of Imperial’s Department of Earth Science and Engineering is more than ready for a fight as he takes his ice axe to the theory. No worries for him that it might meet a frosty reception from some and possibly a heated reaction from many. Well, just as his article was published I caught up with Philip and I first asked him to sum up what the Snowball Earth theory says.

Professor Philip Allen: The hypothesis suggests that the Earth froze over absolutely completely from pole to equator either once or several times a long time ago. We call that deep time because it’s so far away from the present that it defies imagination. It’s six or seven hundred million years ago when life on this planet was barely recognisable from what we have today.

The idea is that the Earth froze over for maybe 20 or 30 million years and then it was very difficult to thaw from this deep freeze. And the reason that the Earth thawed, according to the hypothesis, is that volcanoes emitted the greenhouse gas CO2 into the atmosphere. This built up what might be called a super greenhouse. CO2 concentrations would have been hundreds of times higher than today rather than the twice which is what we fear with current global warming models and therefore it would have taken a long period of time for volcanoes to emit this CO2 to build up the super greenhouse. When the super greenhouse kicked in then it would have been a catastrophic melt back as this ice melted and filled the oceans.

GM: And eventually things stabilised I suppose as far as global temperatures were concerned?

PA: Things started to stabilise after that and that period of stabilisation is also when we get major evolutionary developments with diversification of life. And then we get a further diversification at about 543 million years ago and that’s where life starts to become modern in aspect. So we’re really talking about a period of time when things were widely varying. Climate was oscillating between very hot and very cold probably.

GM: And of course it does sound like a very credible, a very intuitive, hypothesis. It’s gained a lot of currency. Books have been written about it. And yet you’re taking the hypothesis on. In fact you’ve written a review article refuting it in the December edition of Nature Geoscience. So what’s your primary objection to the Snowball Earth hypothesis?

PA: We looked at the sedimentary rocks which were deposited at the actual time of the glaciations, six or seven hundred million years ago. This had really not been done in any detail when the hypothesis was actually made. The hypothesis, by the way, is only 10 or so years old. So by looking at the sediments that were deposited at the actual time of the glaciations we find that there must have been open ocean water. That glaciers must have moved down towards the ocean depositing sediment in the sea. And these glaciers advanced and retreated in cycles of cold and warm, cold and warm. Which is really rather like we have today or at least in the recent past and which would have typified, for example, the margin of the Antarctic ice sheet over the last 15 or 20 million years. So we see far from an Earth that was profoundly and fully glaciated. We see something much more like the more recent history of the Antarctic margin.

GM: But you’ve said yourself that we’re talking about a period in deep time. It’s such an unimaginably long time ago it must be very hard to be completely convinced that the sedimentary evidence that you have relates to that time. That 20 or 30 million year period, a blink of an eye in other words in the context of 700 million years, when it is said that the Snowball Earth effect happened.

PA: We can recognise certain characteristic rock types and we have a fairly sophisticated idea of how they were deposited and where. So these rocks, which I’ve looked at, they were deposited at the fronts of glaciers and they accumulated sediment from floating icebergs and ice sheets. So we’re fairly sure about what kind of environment they were deposited in but it’s another question about when, exactly when. And one has to use as many dating techniques as are available to do this. And we’re still not sure absolutely to the nearest million years when these glaciers existed. We so wish we could accurately date our glacial deposits and currently that’s a field of intense research activity. But one thing we are sure of is that these rocks are old and they’re somehow bracketed by a period of cold which actually we call the Cryogenian, which is a very appropriate label, which existed between about 850 million years ago and around about 635.

GM: So you’re saying that you have a w indow of investigation that pretty comfortably covers the period that advocates of the Snowball Earth hypothesis say the Earth was completely frozen?

PA: Yes, absolutely. You’ve put it very well. But having said that, within this interval there’s great controversy about how the glaciations join up. How the glacial sediments join up. And most consensus is on glaciation that appears to have terminated at about 635 million years ago. And we’ve got two data points for that, Namibia and South China and these glacial sediments have been dated and they appear to terminate at about 635. The jury is out on many of the other glacial successions.

GM: But the Snowball Earth hypothesis, as we’ve said, is incredibly popular and yet here you are writing I’m sure a pretty strongly argued article refuting it in a prominent journal. Do you think this is going to make waves, as it were, amongst the science and geological community?

PA: I certainly hope so. The theory is actually much more popular amongst lay people and amongst the media. It’s a darn good story. I think the flaw with the story is quite simply it’s wrong. So I hope to make waves in the hope that it will stimulate more research so that we can really work out what exactly happened.

GM: But the thing is when you say the flaw in this story is that it’s wrong that sounds incredibly dogmatic. And scientists aren’t meant to be that dogmatic. As a scientist you’re supposed to be open-minded and at least give some credence to the hypothesis before you can then refute it.

PA: Yes. When I say I think it’s wrong it’s that I feel that there is now sufficient volume of evidence that is so hostile to the hypothesis that it’s better to falsify the hypothesis than to build a new one. I think in scientific work one has to at a certain point recognise that a hypothesis is no longer working constructively. Then it’s counterproductive to fiddle around the edges continually changing it so that it morphs into something new with every new discovery. This is not a good way of doing science. We need to test a hypothesis. If it fails the test and if it fails the test on multiple occasions with different multiple sets of data the time comes when you have to say it’s not working or, as I said, it’s wrong let’s build a better one.

GM: It’s fascinating, isn’t it, as a case study as the philosophy of science?

PA: I think so. And there’s something else which is interesting here. The theory, the hypothesis, got into popular media at a very, very early stage. And maybe there’s a warning there that it’s very easy for very interesting unifying ideas like this to have media appeal at an early stage before it has really been subject to the scrutiny of testing with evidence, with data, with a lot of data.

GM: And just finally then, almost coming back to the hypothesis itself, what does it mean for the future of the planet? Because some people have used the Snowball Earth hypothesis to say that we may be kind of leading into that or there may be another Snowball Earth. If all the evidence that you’ve been rehearsing here is correct then how might that change the way we think about the future of the environment and the planet?

PA: Well the first thing I’d say is that if we are running and tuning and calibrating climate models to predict the future then we should not use the Snowball Earth. Climate models should instead, if they want to tune to an extreme climatic state, be going for a deep Earth scenario where there was open ocean. So that’s the first thing I’d say. The other thing I’d say is that it’s simply important to know about origins and the history of the Earth. The darkest history of the Earth is simply important to know about because it happened.

GM: Philip Allen there safe in the knowledge that he’s not exactly on the Christmas card list of Snowball Earth proponents. And in fact if you’re listening to this at the beginning of January you can hear him arguing more of his case on BBC Radio 4’s Material World programme. That’s on January 8th.

Headlines from around the College

Back to today though and let’s have a few headlines from around the Imperial.

High blood sugar and diabetes could be linked to a disruptive body clock and abnormal sleep patterns. That’s according to a study just published by researchers in Imperial’s Department of Genomic Medicine. And that implies that treating sleep disorders could be one way of controlling diabetes and other conditions associated with high blood sugar. Working with colleagues in France, Canada, Denmark and other institutions the team homed in on a genetic mutation associated with high blood sugar and increased risk of diabetes.

Now, the mutation is close to a gene involved with the body clock and sleep hormone melatonin. Spotting these neighbouring genetic attributes gives further evidence at the genome level of the link between abnormal sleep and diabetes. So armed with that insight not only can researchers consider ways of tackling high blood sugar and relative problems by focusing on a person’s sleep but they also have a means of identifying those at greater genetic risk of developing diabetes therefore allowing doctors to intervene earlier to improve health before patients develop the disease.

And Imperial College recently jointly hosted a conference on climate change and carbon storage. The thing is nobody actually turned up. Well, not in real life anyway. Appropriately for the subject, the participants reduced their carbon footprint by meeting up in the virtual world Second Life where people create 3D counterparts of themselves and interact with other citizens in the online world. A scientist attending a conference in First Life is responsible on average for 1.5 tonnes of carbon dioxide, equivalent to the emissions of a London commuter over an entire year.

Staff, or more correctly their avatars, from our Earth Science and Engineering Department joined up with colleagues at the Nature publishing group and proceedings were relayed live by video into lecture theatres across the United States and Imperial’s very own Grantham Institute for Climate Change. Other Second Life users were able to comment and ask questions and topics up for discussion included how to capture carbon from power stations and no doubt other things like, wow, you look great with pink hair and what button do I press again to make my avatar fly that way?

And that was the news. Of course you can stay up to date with what’s going on here at Imperial via our Press Office website and that’s at

Snapshot from Imperial's postgraduate open day

Okay then, so you’ve just done your first degree or maybe you’ve been out working in business or industry or teaching or research and you’re thinking I want to do some further study. Should I go to Imperial as a postgraduate? Well, there are lots of people in this room with that question on their lips. Because this is the postgraduate open day. We have them every year here at Imperial. And various departments and sections showing off their wares here. We’ve got the Careers Advisory Service over here on my left hand side. Surgery, oncology, reproductive biology and anaesthetics over here. Physics, chemistry, the Institute of Systems and Synthetic Biology to name just a few. But let’s home in on them and see what some of these people have to say about why you should come to Imperial as a postgraduate.

Well, here we are at the Electrical and Electronic Engineering stand. This has particular significance for me because I actually did electrical engineering at Imperial many, many years ago. And what are you offering postgraduates?

Voice: We are offering three different MSc courses. One in circuits, one in control and one in communication signal processing. That is for MSc. We are also offering some of the best research teams in Great Britain in control and signal processing, in micro-engineering and microsystems, in analytical digital electronics, intelligent and interactive networks.

GM: Where do your students end up, people who come in and do PhDs or MScs with you? Is it with industry, academia, across the board?

Voice: Well, they do just about everything. We have seen people who have been in academia. We tend to keep some of them, as many as we can. Some others go to other departments. There are entire departments at Imperial which have significant staffing of people who studied in our department. Many people go into industry. Some people found their own spin-off companies. And also some people eventually go and work as financial analysts for major banks and things like that. So it’s really across the spectrum. Government advisors. We’ve seen just about everything.

GM: Simon Leather is with the Biology Department. So what are you offering postgraduates?

Simon Leather: Well, I’m based at Silwood Park and I convene the MScs in entomology, conservation and forest protection, ecological applications and integrated best management and also have oversight over our MScs in conservation science and ecology, evolution and conservation. Basically we offer I guess the best training in all those areas and in particular in entomology which we are unique in the United Kingdom. We’re the only university in the whole of Britain that offers that particular MSc. So if you want to be an entomologist there’s nowhere else to go apart from Imperial. And conservation and forest protection, we are an accredited course. So the Institute of Chartered Foresters have accredited that so we are the only accredited course at Imperial in that subject area.

GM: Now, on this stand is the Imperial College Business School. Stefan Smith is here. So what do you have to offer to postgraduates?

Stefan Smith: We’ve a number of courses available. We’ve got four major Masters programmes based on finance, risk management and financial engineering, actuarial finance and management. We also offer international health management as well in our Masters programmes. In addition we have MBA. We’ve got an MBA programme with three streams. We’ve got a full time MBA. We have an executive MBA programme which runs week days and a weekend MBA programme.

GM: And why should they come to the Imperial College Business School in particular? There are plenty for them to choose from aren’t there? So why Imperial?

SS: I think the unique thing about Imperial’s Business School is it’s small in size. It’s quite intimate in regards to class sizes and interaction with the professors so you get to know them quite well.

GM: But of course Stefan we are in the midst of an economic crisis around the world so is this necessarily a good time to study business?

SS: It’s probably the best time to study business. I think with the changing environment and the landscape of economies worldwide as business changes so will Imperial College change as well in regards as to what they’re teaching and how they’re going to be teaching these students. I think it’s a very good time to embrace what’s happening now.

GM: And I guess when things are tough out there in the economy that’s where being competitive really has the edge. So a few qualifications under your belt may do no harm at all.

SS: Yeah, exactly. I think the better qualified you are in regards to what’s happening now and what’s going to be happening in the future is going to put you in good stead for the future obviously. I mean in 12 to 18 months’ time who knows what the economy of the world is going to be like.

GM: Finally I’m here at the Student Hub with Jo and Darrel. So Jo what’s the Student Hub all about?

Jo: The Student Hub is a one-stop-shop for students. So whereas before they had to walk around the campus to find all their different various answers to questions they come to one place and we’ll answer all their questions here.

GM: And Darrel is that just today for this fair or do you exist in general to advice students about what’s going on here at Imperial?

Darrel: No, the Student Hub is based at the Sherfield Building all year round. We deal with queries such as accommodation, tuition fees, admission queries and lots of general administrative stuff that students have to deal with during the course of the year. So we’re here all year round. Like Jo said, it’s a one-stop-shop for students.

GM: And Darrel tell us what’s the student experience like here at Imperial?

Darrel: Well it’s obviously very multicultural. We have a lot of overseas students and I think for a lot of students it’s a good experience to mingle with people from different backgrounds. Obviously it’s based in quite a central location in London so you’ve got all that London has to offer on your doorstep pretty much.

GM: Educational as well as the cultural. What do you reckon then Jo, why should students come to Imperial?

Jo: As Darrel said, it’s in London. Best city in the world. Lots to offer, lots of experiences and obviously one of the best universities in the world.

GM: Jo and Darrel of the Student Hub at the recent postgraduate study open day.

New head of physics Professor Joanna Haigh on the physics of Earth's climate

Well finally to physics. One of the more male dominated sciences so it’s pretty significant news in the community that the new head of physics at Imperial, one of the three biggest departments in the country, is a woman. Professor Joanna Haigh officially started in-post on January 1st. If the appointment encourages more girls to opt for careers in the physical sciences then nobody would be more delighted than Joanna.

But most of all she has her eyes on building on the many successes of the department that she now leads. In fact the last few months have been quite a rollercoaster for Joanna. When the top job came up she was just settling in to her post as the head of the Space and Atmospheric Physics Group, a role that she held for about 1 8 months before becoming head of department. So when I met her the other day we began by talking about the activities of that group.

Professor Joanna Haigh: Well, in the group we studied the physics of essentially the planetary system of the planets. The interplanetary magnetic field, the physics of the Sun and the physics of the Earth’s climate right the way down from the upper atmosphere down to the surface and the oceans. And we do that by using a range of techniques. We have instruments on satellites. A recent advance in space magnetometry has allowed a satellite to look around at the interplanetary magnetic field and understand how it’s structured and its interaction with the solar wind.

And we have people who are interested in the planetary atmospheres, upper atmospheres of particularly some of the planetary satellites like Titan. Looking at the ionised atmospheres of those planets. And then we have the people that are interested in the Earth’s atmosphere, particularly the physics of the Earth’s atmosphere. Clouds and radiation. Air pollution. Studies of the spectroscopy of the gases in the atmosphere. And the ocean circulations and the interaction between the oceans and the atmosphere and the heat and thermodynamic budgets of those.

GM: As for your own work, I know that you’re very interested, for instance, in clouds and the role that cloud plays either in warming the planet I assume by trapping in the warmth but also reflecting the Sun’s energy. I wonder if you can tell us more about that.

JH: The work I’ve been doing over the years has been in looking at these radiative processes in the atmosphere. Certainly the interaction of radiation with the cloud and also with gases, some of the greenhouse gases, also some of the gases that absorb solar radiation and how the heating that’s introduced by these gases and clouds and things into the atmospheric circulation might change climate and have an impact at the surface. So in the atmospheric physics group here we have a strong observational component. My colleague John Harries has the first ever geostationary radiation budget experiment up on the Meteosat satellite. He and his colleague Juliet Pickering are involved in airborne far-infrared spectroscopy where they’re looking at the effect of water vapour on the radiation budget of the Earth. My colleague Ralf Toumi has interests in monitoring air pollution in and around London. And all of these different aspects are feeding into our theoretical studies.

GM: And of course all this feeding into decision making and policy right at the highest level and in fact you’re involved in the Inter-governmental Panel on Climate Change, obviously in a scientific context. So can you just talk me through some of that?

JH: IPCC is the international body that produces reports every five to seven years on essentially the state of the art of climate science. And this is used to inform the policy makers and the governments as to what we understand about the climate system, how it’s changing, why it’s changing and to inform their decisions on what might be done about it. So I was most involved in the third assessment report which was produced in 2001. And on that I was a lead author and I had particular responsibility for looking at how changes in solar radiation might influence climate and to what extent that has influenced recent climate change.

GM: So you are the new head of physics here at Imperial College. You’re a female physicist, obviously, and to many people that would be a surprise. I mean that in a good way. A delightful surprise obviously. Given that physics is so often thought of as being a boy’s subject has that changed, is that now changing?

JH: If only I think. I’m lucky. I’ve had a splendid career. I’ve really enjoyed myself and I haven’t, I don’t think, been subject to much discrimination or anything like that. But the sad state of affairs is that 18 year old or perhaps 16 year old girls don’t want to do physics as much as the boys do. So however hard we try to get more and more girls into do undergraduate studies in physics here we’re sort of teetering around the 17 to 22 per cent mark and have been for the past 20 odd years. There are more and more female lecturers coming through, which is great. So this will eventually feed through to the senior staff and perhaps girls in schools will see this as a positive signal. But I’ve got a feeling that it’s not like that. I think it’s how physics is presented to 14 to 16 year olds that’s really the key. That’s really going to turn girls on or off physics.

GM: Do you think there’s a tendency even at school level for girls just to find themselves gravitating towards the life sciences and the boys more towards physics, maths and engineering?

JH: I think that’s true and it’s quite interesting to think about why that might be. And I’m sure teachers are trying their best to keep people interested in all aspects of science but there is a positive feedback in the sense that there’s not enough specialist physics teachers in schools and so physics tends to get taught by teachers who are specialists in other aspects of science. And because the boys have done the physics and the girls have done the biology the role models there tend to be the boys getting the encouragement from the male teachers to do physics. And this is sort of a positive feedback effect. All that we can try and do is get girls in at an earlier stage I think.

GM: Finally then, I suppose in the sales pitch for physics, because we know that recruitment is doing very well in the physics department at the moment, and I just wonder why. Is it partly the CERN effect, you know, particle physics, lots of people talking about that and obviously your area in terms of climate change and atmospheric physics? It’s pretty high profile stuff I suppose.

JH: That’s true. I’m not sure. We have a fantastic admissions team here and they’re trying to understand why these effects are going on. I don’t think it’s the applied side. I think the applied side actually might appeal more to the girls. You know, the environmental and the bio-physics and that sort of thing appeals to people who want to apply the physics to real world situations. But when we look at the people that we interview, the 18 year olds that we interview, they still want to do whiz-bang physics. They want to do energetic particles, cosmology, string theory and all these things that you see in New Scientist. So I’m not quite sure why there’s this increase in numbers. Perhaps that in the current economic climate students want to spend their money on something solid rather than something a little bit more indefinite. I don’t know.

GM: Joanna Haigh. And that’s it for the January edition of this podcast but do come back again next month, won’t you, when I’ll have more top stories from Imperial and no doubt more of this music. Our theme tune is written by Oscar Buldum. Here more of his work at This podcast is jointly hosted by the Imperial Press Office and our lot over in the Science Communication Group. The producer is Helen Morant and I’m Gareth Mitchell. Thanks very much for listening to this edition and I’ll look forward to seeing you next time. Bye for now.