Author Archives: B Merritt

Asteroids

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This post was contributed by Paola Bernoni and Anja Lanin, students on Birkbeck’s BSc Geology.

What can asteroids tell us about the formation of the solar system about 4.6 billion years ago and how are we able to extract such information from objects that are located in a region, the Main Asteroid Belt, somewhere between Mars and Jupiter, several hundred million miles from the Sun? This was the subject of the lecture delivered by Professor Hilary Downes of Birkbeck’s Department of Earth and Planetary Sciences for this year’s Science Week on Thursday 3 July, her debut talk for the event despite Professor Downes’ long association with Birkbeck.

Asteroids: what, where, when?

First of all, what are asteroids?  Remnants of cosmic material unable to accrete and form a planet-sized object. In the Main Asteroid Belt this was due to the gravitational pull of the giant planet Jupiter: hence asteroids are a “failed planet”, not – as one might be led to believe – fragments of broken-up ones.   We are mainly interested in asteroids whose orbits cross that of the Earth and Mars as they are most likely to yield useful information about our own planet.

What do they look like? “Potato shaped”, or long and thin, but invariably irregularly shaped, their surfaces pock-marked with impact craters … not volcanic craters as, unlike the volcanically active Earth, asteroids are dead bodies that have lost all of their internal heat.

What do we know about asteroids and how do we know it?  

Near-Earth asteroids are occasionally knocked out of the Main Belt and can even end up colliding with the Earth: these are meteorites.  In 2008, for the first time ever, an asteroid was detected prior to impact and predicted to land in North Sudan, where researchers flocked to recover 600 fragments, after it had exploded in the atmosphere.  The more recent impact at Chelyabinsk in the Southern Urals, Russia, was even filmed.

Space missions have collected useful information: there has even been a landing on asteroid  Itokawa in 2005, which managed to collect some dust material.  The ongoing Dawn mission, departed in 2007, reached Vesta in the Main Belt in 2011, orbited around the asteroid for one year and then departed for Ceres, where it is expected to arrive in 2015.  Why the interest in Vesta and Ceres? These are two of the largest surviving protoplanetary bodies that nearly became planets and therefore can help us gain a better understanding of the evolution of the solar system and of the processes that led to the formation of differentiated, layered bodies like the Earth (and Vesta) and less differentiated bodies (Ceres).

Measurements of radioactive decay of different isotopes performed on meteorite fragments have yielded consistent results on their age: they are as old as the solar system (4.6 billion years), a result matched by the results on the oldest terrestrial zircons. Yet there are some younger meteorites and they come from the Moon or Mars.

How do we classify asteroids and why?

The traditional classification of meteorites based on composition – iron, stony and stony iron – does not really tell us much, a discrimination based on provenance might be a better option:  whether meteorites come from a layered body, such as the Earth, with a nickel-iron core, an olivine-rich mantle and a silicate feldspar-rich outer shell, the crust,  or not … hence the interest in the layered Vesta and the less layered Ceres, which is made of a rocky core,  a water-ice layer and a thin crust.  But many of the recovered meteorites, especially from Antartica, do not show signs of provenance from a layered body: called “chondrites” as they containing  small globules, chondrules, which are some of the earliest materials formed in our solar system, they are unfortunately not very useful in the quest for a better understanding of our layered Earth.  Iron meteorites, compositionally similar to the Earth’s core, are thought to represent the core of small asteroids that blew apart and lost the encasing mantle. We have some 50 specimens, but it is a biased sample: they are more resistant passing through the atmosphere and easier to detect on the ground. Stony-iron meteorites are very rare instead: as they also contain an iron-nickel alloy, and olivine, one of the main components of the Earth’s mantle, they are thought to represent the core-mantle boundary of the parent asteroid, which was hot enough to commence differentiation.

Asteroids and Research at Birkbeck

Professor Downes then gave some highlights on the research underway at Birkbeck where stony meteorite samples from a very old, unknown asteroid are studied to establish similarities with the Earth’s mantle. Their olivine and other silicates are surrounded by carbon, including tiny diamonds, and nickel-iron rims, whilst on Earth these metals have segregated into the core and carbon is found in organic matter. The meteorite minerals show evidence of shock from impact and the carbon component also shows that graphite has been shocked into diamond. Compositional analyses have shown the presence of a known mineral, Suessite and an unknown mineral made of 91% iron and 9% silica, which is the most likely composition of the Earth’s core whilst the composition of meteorites originated from the outer shell of layered asteroids is similar to that of the basaltic rocks we find at the Earth’s surface.

Professor Downes finally underlined the uniqueness of the Earth amongst the rocky planets with the continued presence of water – lost on Venus and Mars – and  especially of life, which is not known to have ever developed in any of the other terrestrial planets. The question of where Earth’s water came from is still open. A “meteor shower” of questions then followed, on the provenance of water and life on Earth, the age of meteorites found in Antartica and what drives differentiation: for some of these matters the audience was referred to courses offered by the Department of Earth and Planetary Sciences … for others to Birkbeck’s astrobiologists.  Finally, the talk and the Q&A session came to an end but the opportunity was available to carry on with discussions and queries helped by a nice glass of wine and nibbles.

Dicken’s Day 2014: Dickens and Conviviality

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This post was contributed by Birkbeck alumnus Dr Ben Winyard, who is one of the organisers of Dickens Day. Join Birkbeck’s Centre for Nineteenth-Century Studies as we read Our Mutual Friend month-by-month in its original instalments.

charles_dickens

Charles Dickens

Now in its twenty-eighth year, Dickens Day enjoys a uniquely mixed audience of Dickens enthusiasts, academics, and students at all levels of study. It is perhaps apt then, that this year’s theme was ‘Dickens and Conviviality’, as this one-day conference, jointly run by Birkbeck, the University of Leicester and the Dickens Fellowship, brought together over one hundred Dickens aficionados for a day of genial intellectual exchange.

Dickens was associated with good humour, bonhomie and sociability from the outset of his career. Before his first novel, The Pickwick Papers, had even concluded its run of monthly instalments (1836–1837), its twenty-four-year-old author had been catapulted to fame and was widely lionised, and even mythologised, as the proponent and exemplar of merry-making. Indeed, Pickwick is famously stuffed with eating, drinking and parties, dances, celebrations, picnics and all manner of sociable endeavours. Like many of his contemporaries, Dickens held that laughter possesses a unique ability to harmonise and heal. One of our speakers, Clive Johnson, observed that if Freud understood humour in economic terms as a ‘wasteful’ element in the psychic economy, for Dickens, writing in an era sharply defined by an imaginatively parsimonious political economy, this was actually a great positive.

Dickens went on to consolidate this image of himself as a master of conviviality in his own life: he was notorious for his love of parties, impromptu dinners, jamborees, skits, celebrations, practical jokes, amateur theatrics, and many other forms of high-spirited sociability. He also assiduously cultivated many friendships with some of the leading authors, politicians, artists, thinkers, philanthropists and actors of his age, and he was a notably prolific letter writer in an era famous for its voluminous epistolary correspondence.

It is as the exemplar of Christmas spirit that Dickens is perhaps most firmly lodged in the popular cultural imagination; he is even erroneously praised for ‘inventing’ Christmas in its modern, recognisable form. Even in Sketches by Boz (1836), his first published collection, Christmas is warmly lauded for stoking mutual affection:

‘Christmas time! The man must be a misanthrope indeed, in whose breast something like a jovial feeling is not roused – in whose mind some pleasant associations are not awakened – by the recurrence of Christmas. […] Who can be insensible to the outpourings of good feeling, and the honest interchange of affectionate attachment, which abound at this season of the year? […] There seems a magic in the very name of Christmas. Petty jealousies and discords are forgotten: social feelings are awakened in bosoms to which they have long been strangers’.

The later image of the joyous Cratchits in A Christmas Carol (1843) remains one of Dickens’s most famous depictions of good feeling, emblazoned on our collective memory from multiple versions of this perennial classic.

However, Dickens was also deeply interested in the flipside of conviviality and it is interesting that another paradigmatic Dickensian vignette is the starving, bedraggled Oliver Twist holding up his empty bowl and asking for more. One of the day’s plenary speakers, Wendy Parkins, reminded us of the ethical injunction to care for the vulnerable, especially children, that Dickens evokes, citing the neglected Jellyby children in Bleak House (1852–53). For Dickens, hospitality, like philanthropy, is a duty of care that we all owe to those in need. Asking for more, like Oliver, is also a rebellious assertion of individual need in a system that conglomerates and marginalises the poor. One of the fascinating threads of the day was the constant slippage in Dickens between needs, desires and wants, and the interconnectedness of physical need with emotional, social and sexual needs and desires. In Dickens, ‘hunger’ operates metaphorically as well as literally. Indeed, Jo Parsons reminded us of Dickens’s own childhood experiences of physical and emotional hunger that echo through his work, in particular David Copperfield (1849–50), and which perhaps explain his wish, shortly before his death, to compose a cookery book.

Indeed, despite his reputation as a sort of literary Father Christmas, Dickens also depicted disastrous and terrifying Christmas scenes: most famously, Pip’s excruciatingly anxious Christmas dinner in Great Expectations (1860–1861), as he endures the moralising insults of the adults and awaits the discovery of his theft of food for the escaped convict Magwitch. Dickens’s final, unfinished novel, The Mystery of Edwin Drood (1870), reaches a climactic point with the disappearance of the eponymous hero on a particularly fevered and gloomy Christmas Day. Despite this, Pete Orford, creator of the Drood Inquiry revealed how early reviews of Drood foregrounded the novel’s humour and compared it to The Pickwick Papers, despite its gothic themes of drug addiction, madness and murder. As Orford showed, Dickens was a master of alternating light and dark, moving swiftly between humour and more ominous, tragic tones.

Most of our speakers were reluctant to take Dickens’s representations of good-humoured sociability at face-value, with most papers focusing conversely on loneliness, isolation, poverty and want, social aping and pretension, and the feelings of inadequacy, anxiety and exclusion that may actually fuel conviviality. As Nicola Bradbury observed, Pip’s Christmas dinner is made entirely miserable by the appalling company – in Dickens, hell really is other people. Charlotte Boyce considered the hidden class dynamics of Pickwickian sociability; somebody low-paid and low-status prepares, serves and clears up all those extravagant, jolly meals. Harriet Briggs considered how Dickensian laughter may be hearty and boisterous but is rarely anarchic, often operating to dissolve discontent and smother rebellious impulses. As the day’s keynote speaker, Malcolm Andrews, observed, humour in Dickens is both social glue and a social corrective.

Dickens Day is famous for its readings and this year’s – David Copperfield’s hilariously drunken disaster of a dinner party and the sham society wedding of the Lammles in Our Mutual Friend (1864–65) – further confirmed that Dickensian conviviality is often at its most hilarious when it is faked, strained, overegged – or otherwise goes horribly wrong. Fortunately, no such disasters befell this year’s event, which is already looking forward to celebrating its thirtieth anniversary in 2016.

From the Abercrombie Plan to Abercrombie & Fitch: A cultural history of East London in an evening of films

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This post was contributed by Andrew Whittaker, a local Forest Gate resident.

I recently had the opportunity to attend the latest in a series of workshops called “East London In Flux” organised by Fundamental Architectural Inclusion and Birkbeck, University of London. This was an evening of films, ranging from the postwar Abercrombie Plan to young people’ views on the Olympics, Westfield (hence the title) and their local area. The films from the 1940s were fascinating and I was surprised at how industrial London was, with rows of cranes at Tower Bridge to unload cargo ships into the warehouses lining the Thames. This was particular true in East London and the second film about West Ham described how washing hung out to dry was often made dirty again by the smoke coming either from the large factories in Stratford or the ships coming into harbour in the docks.

It was also interesting to see the changing culture of architecture over the last seventy years, from the centralised, technical-rational certainties of the 1940s through to the more fluid realities of the current day. In the first film, it was ironic to hear Abercrombie talk of his plans clearing away the ‘bad and ugly things’ of the past, when the modernist architecture of the 1960s is often regarded in a similar way. This was brought home in the Fundamental film ‘Watts the point’, which featured the demolition of a tower block in 2003 and the reactions of former tenants and local people. While such events are often viewed as a triumphant clearing away of the bad and ugly reminders of the sixties, the film captured the most complex feelings evoked in the ex-residents who had spent a significant proportion of their lives there.

One of the recurring themes of the evening was the changing nature of architecture and public involvement. We heard that there were extensive surveys done to gauge public reactions to the Abercrombie Plan in the 1940s, which was quite well-meaning and probably quite genuine. But this was public involvement done on the planners’ terms – they decided what questions to ask the public, which probably followed their own dilemmas and concerns, not those of the public.

This contrasted with the later films about young peoples’ views, which were more interesting and engaging. My two favourites were films about the ‘architecture crew’, a group of local young (13-19 years) who were interested in architecture and it’s contribution to their everyday environment. In the first film, they travelled to St Paul’s to learn more about London’s architectural past and in the second, they discussed how they had researched the history of Newham as a port and industrial area in the lead up to the Olympics. In both films, the passion, enthusiasm and curiosity of the young people came over as they learnt about the history of their city and developed a sense of ownership of the area where they lived. The films documented how they had found a voice and had been influential in major changes such as the Olympics and had obviously had a lot of fun on the way!

Redesigning Biology. Birkbeck Science Week 2014

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This post was contributed by Dr Clare Sansom, Senior Associate Lecturer in Birkbeck’s Department of Biological Sciences. 

Dr Vitor Pinheiro (right) and Professor Nicholas Keep, Dean of the School of Science

Dr Vitor Pinheiro (right) and Professor Nicholas Keep, Dean of the School of Science

The first of two Science Week talks on Wednesday 2 July was given by one of the newest lecturers in the Department of Biological Sciences, Dr Vitor Pinheiro. Dr Pinheiro holds a joint appointment between Birkbeck and University College London, researching and teaching in the new discipline of synthetic biology. In his talk, he explained how it is becoming possible to re-design the chemical basis of molecular biology and discussed a potential application of this technology in preventing contamination of the natural environment by genetically modified organisms.

Synthetic biology is a novel approach that turns conventional ways of doing biology upside down. Biologists are used to a “reductionist” approach to their subject, breaking complex systems down into, for example, their constituent genes and proteins in order to understand them. In contrast, synthetic biology is more like engineering, a “bottom-up” approach that tries to assemble biological systems from their parts. Pinheiro introduced this concept using a quotation from the famous US physicist Richard Feynman: “What I cannot create, I cannot understand”. Synthetic biologists often use vocabulary that is more characteristic of engineers or computer scientists: words like “modules”, “device” and “chassis”.

All life on Earth is dependent on nucleic acids and proteins; the former store and carry genetic information, and the latter are the “workhorses” of cells. They are linked through the Central Dogma of Molecular Biology which states, put somewhat simplistically, that “DNA makes RNA makes protein”. The information that goes to make up the complexity of cells and organisms is held in DNA and “translated” into the functional molecules, the proteins, via its intermediate, RNA. The mechanism through which the biology we see now arose – evolution – is well enough understood, but it is not yet clear whether evolution had to create the biology we see today or if it is a kind of “frozen accident”. There is, after all, only one “biology” for us to observe. But synthetic biologists are trying to build something different.

DNA is made up from three chemical components and structured like a ladder: the rungs are made up of the bases that contain the information, and sugar rings and phosphate groups make up the steps. All three components can be chemically modified, affecting the physical properties and the potential for information storage of the resulting nucleic acid. Any modifications that do not disrupt the natural base-pairing seen in DNA and RNA can be exploited to make a nucleic acid that can exchange information with nature. And if the enzymes that in nature replicate DNA or synthesise RNA can also be exploited to synthesise and replicate these modified nucleic acids, that process will be substantially more efficient than chemical replication. Modification of different components presents different re-engineering challenges and different potential advantages. Sugar modifications are not common in biology and are expected to be harder than nucleobases to engineer. On the other hand, they are expected to increase the resistance to biological degradation of the modified nucleic acid. These synthetic nucleic acids have been generically termed “XNA”.

Pinheiro, as part of a European consortium, led the development of synthetic nucleic acid in which the natural five-membered sugar rings had been replaced by six-membered ones. They are more resistant than DNA to chemical and biological breakdown, and have low toxicity, but are poor substrates for the polymerases that catalyse DNA replication and RNA synthesis. Further, he has harnessed the power of evolution to create “XNA polymerases” through a process called directed evolution. In this, hundreds of millions of variant polymerases are created and those that happen to be better able to synthesise the selected XNA are isolated. The process is repeated until the best polymerases are identified or isolated polymerases have the required activity.

These synthetic nucleic acids, however, still cannot be involved in cell metabolism and this is a current research bottleneck that prevents the development of XNA systems in bacterial cells. An alternative route towards redesigning biology would be to modify how information stored in DNA and RNA is converted to proteins: redesigning and replacing the genetic code. The exquisite fidelity of the genetic code depends on another set of enzymes, tRNA synthetases, which connect each amino acid to a small “transfer” RNA molecule including its corresponding three-base sequence or codon. This allows the amino acid to be incorporated into the right place in a growing protein chain. In nature, almost all organisms use the same genetic code. Synthetic biologists, however, are now able to build in subtle changes so that, for example, a codon that in nature signals a stop to protein synthesis is linked to an amino acid, or one that is rarely used by a particular species is linked to an amino acid that is not part of the normal genetic code.

Any organism that has had its molecular biology “re-written” using XNA and non-standard genetic codes should be completely unable to exchange its information with naturally occurring organisms, and, therefore, would not be able to flourish or divide outside a contained environment: it could be described as being contained within a “firewall”.  It would therefore lack the risks that are associated with more conventionally genetically modified organisms: that it might compete with naturally occurring organisms for an ecological niche, or that modified genetic material might spread to them. If, or more likely when, these “genetically re-coded organisms” are released into the environment (perhaps to remove or neutralise pollutants) they will not be able to establish themselves in a natural ecological niche and will therefore pose negligible long-term risk. The more such organisms deviate from “normal” biology, the safer they will become.