ISSUE 5 January 2021 Shivanshi Bhatt
INSIDE THIS ISSUE PG. 2 Jordan Curves & Drawings
Lightning illuminates the Florida sky behind the SpaceX Falcon 9 rocket, topped with the Crew dragon spacecraft, as it sits on the Launch Complex 39A the day before lift off. Credits: Bill Ingalls, NASA
CAFÉ SCIENTIFIQUE :
Gene editing in Mice
THE NEWSLETTER
PG. 3
EDITOR’S NOTE: QUATERNIONS
The Future of Supersymmetry The Quantum integrated Network
PG. 4 Photon Avalanches The Power of a Supernova
PG. 5 Methane as rocket fuel How Heavy is Dark Matter?
PG. 6-8 Latest News and headlines Media Recommendations
I’ve talked about number systems in the past, but today I’d like to take a look at a number type: the quaternions. Just as the real numbers are one-dimensional, and complex numbers are made up of 2 parts, real and imaginary, the quaternions are also linked to a certain number of dimensions: 4. But what ‘are’ these numbers, and why do they matter? To describe a rotation in 2 dimensions, you need two-dimensional numbers (multiplying complex numbers adds the angles, hence results in a rotation). So what about rotations in three dimensions? Three-dimensional numbers? Irish mathematical William Hamilton was thinking about this problem and realised that it didn’t seem to work in 3 dimensions, and while strolling along the canal in Dublin, he came to the realisation that he needed not 3, but 4 dimensions in order to describe 3D rotations. So flushed with the excitement of his discovery, he ran to a nearby bridge and carved the rules that he needed, which unfortunately isn’t there anymore but has been honoured with a plaque with the rules of quaternions, and is now a favourite mathematical site. These numbers are used in computer graphics, calculating the orientation of space shuttles and the orientation of smart phones. Now you might be thinking, we have the reals, complex and now quaternions- is there a step up? And yes, the octonions, 8-dimensional numbers. However as we go up the ladder of dimensions, we lose properties such as order of operations (i.e ab = ba) and more. This lack of structure unfortunately makes higher order numbers less useful, however they are amazing nonetheless! Shivanshi ☺
JORDAN CURVES & DRAWINGS Click here to read the paper, and here for the summarised article. Researchers at the TCS Robotics Research Lab in India have recently developed an artificial intelligence system that can automatically convert an image of a person’s face into a recognisable non-self intersecting loop, known as a Jordan curve. After reading about Jordan curves, Aniruddha Singhal, one of the researchers who carried out the study, started investigating that possibility of automating producing TPS art (the travelling salesman problem, a famous problem in computer science showing an intractable problem, a problem for which there exists no algorithm that can be completed in linear time). In collaboration with his colleagues, created Chitrakar, a system that can transform an image into a drawing composed of a single, long line, ultimately turning it into a Jordan Curve. Remarkably, it can produce drawings with an ‘acceptable result’ in less than 30 minutes. The system uses state-of-the-art deep learning techniques to segment the human face from a photo and combined with image enhancement techniques. The enhanced image is stippled, and the points are connected by a TPS solver, where each point is assumed to be a destination of the travelling salesman. The final route of the salesman is converted to a Jordan curve by an intersection removal technique. Learn more about the latest developments for the solutions to the travelling salesman problem here .
An example of the System’s creations. Credit: Singhal et al.
PREMATURE AGING & GENE EDITING Click here to read the full article
Mice with premature aging syndrome at 7.5 months with no treatment (left) and those with the base editing at 11 months (right). Credits: Science Mag
Around 400 people in the world are estimated to have Hutchinson-Gilfrod progeria syndrome, which results from a single base change in the gene for a protein called lamin A, which helps support the membrane forming the nucleus in the cells. The resulting abnormal protein, called progerin, disrupts the nuclear membrane and is toxic to cells in many tissues. Toddlers who have this soon become bald, have stunned growth and wrinkled skin. David Liu of Harvard University and the Broad institute turned to base editing to try and disrupt the active of the mutated gene for lamin A in mice. The results were incredible; when the mice were examined 6 months later, between 20% and 60% of their bone, skeletal muscle, liver, heart and aorta carried the DNA fix. Although the mice were already 2 weeks old, their aortas months later bore virtually no signs of the fibrous tissue growth or loss of smooth muscle cells seen on mice and children with progeria. The goal is now to perfect this and to hopefully get funding to launch a clinical trial, so that this procedure can be carried out on children.
THE FUTURE OF SUPERSYMMETRY Click here to read the full article Supersymmetry is the idea that the fundamental particles of nature are linked through a deep relationship, connecting the fermions and bosons together. Fermions are the ‘building blocks’ of the universe; all the quarks, electrons, neutrinos, muons- they are what all matter (aside from dark matter) is made from. In contrast, bosons are the carriers of the fundamental forces of nature. The electromagnetic force is carried by the photon, the weak nuclear has 3 bosons, the W+, W- and Z and the strong force has its own 8 bosons which allow it to permeate. Gravity has a hypothetical boson, the graviton, but we currently have little understanding of it, or even know if it exists, or if gravity is an exception to this pattern. Another mystery of the universe is why these particles are all split into these 2 sections and if there lies a deep relationship between them. Symmetry is a key idea in all of physics, and with it we have been able to understand many relationships and fundamentals, such as the principle of the conservation of Energy. The theory that links together the fermions and the bosons is called supersymmetry. It states that fermions and bosons have more than just a connection, that they are in fact, two sides of the same coin. That every single fermion has a mirror-like particle (not to be confused with mirror matter) in the boson family and vice versa. In the supersymmetric landscape, each partner of a fermion gets an ‘s’ attached to it; the partner of a quark is a squark, and the partner to an electron is a selectron. For the bosons, the chosen suffix is ‘ino’. Therefore gluons are linked to gluinos etc. In a perfectly symmetric world, we would see these twinned particles everywhere. But we don’t, and that’s as the symmetry could only survive in the hot an dense climate of the early universe. As the universe expanded, it cooled and broke the symmetry, diving the fermions and the bosons; the only way to recreate these conditions is in a particle collider. The Large Hadron collider was explicitly designed to hunt for signs of supersymmetry, but after years and years of searching? Nothing. These are still no sign of any supersymmetric particle. In fact, now many supersymmetric models are completely ruled out, and very few theoretical ideas remain. While this theory has enjoyed much widespread support, the theory has been on thin ice ever since the LHC turned on, and so the future of the theory is in serious doubt. So where will physics go from here? Only time, and lots of maths will tell.
QUANTUM NETWORK Click here to read the full article Chinese scientists have established the world’s first integrated quantum network, combining over 700 optical fibres on the ground with two ground-to-satellite links to achieve quantum key distribution over a distance of 4,600 kilometres for users across the country. Unlike conventional encryption, quantum communication is considered unhackable, and therefore the future of secure information transfer for banks, power grids and other sectors. The core of quantum communications is quantum key distribution (QKD), which uses the quantum states of particles to form a string of ones and zeros; any eavesdropping between the sender and the receiver will change this string or key and will be noticed immediately So far, the most common QKD technology uses optical fibres for transmissions over several hundred kilometres. Using trusted relays, the ground-based fibre network and the satellite-to-ground links were integrated to serve more than 150 industrial users across China, including state and local banks, municipal power grids and e-government websites. This work shows that quantum communication technology can be used for future large-scale, practical applications.
An illustration of the basics of QKD. Credits: Quantum Flagship
Optical fibre used in communication. Credits: Britannica
GIANT PHOTON AVALANCHES Click here to read the full article In some materials, the absorption of a single photon can trigger a chain reaction that produces a large burst of light; the discovery of these photon avalanches in nanostructures opens the way to imaging and sensing applications. The rich energy-level structure of ions from the lanthanides series of elements allows them to be used for a process known as photon upconversion- in which two photons are combined to generate one higher-energy photon. Nanoparticles that emit upconverted photons can be used in imaging techniques to produce pictures that are free from background signals, thereby giving them an edge over other fluorescent probes used for imaging. A special type of upconversion called photon avalanching can occur in nanoparticles that contain lanthanide ions. This phenomenon has previously been observed only in millimetre-to-centimetre scale crystals, and might enable a variety of laser applications. Lanthanidedoped materials emit light with a narrow range of frequencies, which can be tuned from infrared to ultraviolet. This effect has underpinned most artificial light sources for decades, but research into these materials was given a further boost when lanthanides were incorporated into nanoparticles, and are now being researched particularly intensively because to their widespread application in bioimaging, nanothermometry and diagnostics for cancer and COVID-19.
THE SECRET TO SUPERNOVAS Click here to read the full article Before, neutrinos were proposed to be the driving force behind supernovas, however over the decades, physicists have constantly bumped into what appeared to be a flaw in the neutrino-powered models. Neutrinos are famously aloof particles, and questions remained over exactly how they transfer their energy to the star’s ordinary matter under the extreme conditions of a collapsing star. Whenever theorists tried to model these interactions in computer simulations, the supernova’s shock wave would stall and fall back on itself. However in recent years, we have been able to hone in on the surprisingly complex mechanisms that make supernovas tick. For much of a star’s life, the inward pull of gravity is delicately balanced by the outward push of radiation from the nuclear reactions inside its core. This core collapses in on itself causing the temperatures to surge to 100 billions degrees Celsius and fusing the core into a solid ball of neutrons. The outer layers of the star continue to fall inward,
Photon Avalanche (PA) Unconverison. Credits: Edinburgh Instruments
Supernova 1987 before (right) and after (left) it exploded. Credits: NASA
but as they hit this incompressible neutron core, they bounce off it, creating a shock wave. In order for this to become an explosion, it must be driven outward with enough energy to escape the pull of the star’s gravity. Up until recently, the forces powering the shock wave were only understood in the blurriest of terms, but now with the growth of super computers, we have been able to model massive stars with the complexity needed. This simulations have found that inside the star, the particles twist and turn chaotically; this turbulence creates extra pressure behind the shockwave, pushing it further from the star’s centre. The turbulent matter bouncing around behind the shock wave also has more time to absorb neutrinos. Energy from the neutrinos then heats the matter and drives the shock wave into an explosion. For years, researchers failed to realise the importance of turbulence, as it only reveals its full impact in simulations run in three dimensions. These simulations have also revealed that turbulence results in an asymmetric explosion, where the star looks a bit like an hourglass; as the explosion pushes outward in one direction, matter keeps falling onto the core in the other directions, fuelling the star’s explosion further. Due to the latest discoveries, we are now beginning to tackle problems that were previously unimaginable.
METHANE ROCKET FUEL ON MARS Click here to read the full article Going to Mars has long been one of humanity’s goals- but if we use all the fuel for the journey, how will the future astronauts get back home? According to a new study, they could make rocket fuel from the methane that’s already on the red planet. Researchers have devised a new way to create methane-based rocket fuel that they hope could make return trips from Mars far more feasible. This method was previously theorised by Elon Musk and engineers at SpaceX, who considered ways to use carbon dioxide and water from ice on Mars to have the carbon and hydrogen necessary to create methane. So, in theory, future astronauts could use this technique to turn local Martian materials like ice and carbon dioxide into rocket fuel for a return trip home. So far, this new method is only a ‘proof of concept’, meaning that it has only been tested in labs and not in real like situations, however while lots of engineering and research is needed before it can be fully implemented, the results are very promising. To create this method, the team took an existing two-step method to turn water into breathable oxygen, used on the International Space Station, and made it into just one step, using a single-atom zinc catalyst. This makes the mechanism more compact and portable, and thus easier to use for the Mars project. Currently, many launch vehicles don’t use methane based fuel, so this process would have to be compatible with further propulsion technologies. However methane-based fuel can have a number of advantages over other types that could potentially leave carbon residue in rocket engines that need to be cleaned, which could be simply not possible to complete on Mars. However some companies are looking into methane-based fuel and hopefully this system will be implemented for the future astronauts who will go to Mars.
A concept design showing the future astronauts on Mars. Credits: NASA
THE MASS OF DARK MATTER Click here to read the full article Dark matter comprises approximately 75% of all matter in the universe and yet we cannot see it. Scientists have calculated the mass range for dark matter and it’s much tighter than the science world would have thought. The findings radically narrow the range of potential masses for dark matter particles from 10^-24 eV – 10^19 eV originally, to 10^3 – 10^7 eV; they have shown that dark matter cannot be either ultra-light, or ultra heavy. What makes this even more significant is that if the actual mass of dark matter is outside of this range, then it will prove that an additional force- as well as gravity- acts on dark matter.
HEADLINES AND STORIES MEXICO CITY BAN ON SINGLE-USE PLASTICS TAKES EFFECT -
A broad ban on single-use containers, forks straws and other items takes effect in Mexico’s capital, one of the world’s largest cities after more than a year of preparation. The law has been in place since last year, however they are now taking effect, with more biodegradable bags becoming common at the city’s street food stalls, and plastic straws are offered less often.
JOE BIDEN NAMES TOP GENETICIST ERIC LANDER AS SCIENCE ADVISER -
US president Joe Biden has chosen the decorated geneticist Eric Lander as his presidential science adviser and the director of the Office of Science and Technology Polity (OSTP). Lander was a key figure in the Human Genome Project and is the president and founding director of the Broad Institute of MIT and Harvard in Cambridge, Massachusetts. He will also be the first biologist to run the OSTP.
AUSTRALIAN LUNGFISH HAS THE LARGEST GENOME EVER SEQUENCED -
Siegfried Schlossnig at the Research institute of Molecular Pathology in Australia and his colleagues have found that the lungfish’ genome is 43 billion base pairs long, which is around 14 times larger than the human genome. It is 30% larger than that of the previous record holder: the Axolotl, a Mexican amphibian that the team sequenced in 2018.
NASA’S MARS ROVER PERSEVERANCE LANDS ON MARS IN LESS THAN A MONTH -
On February 18th ,the car-sized rover, the core of NASA’s $2.7 billion Mars 2020 mission will land on the floor of the 45 kilometre wide Jezero Crater, which once hosted a lake and a river delta billions of years ago. On its journey, Perseverance will scour the crater for signs of ancient martian life and collect and cache dozens of samples. If all goes to plan, these samples will be brought back to earth as early as 2031 by a joint NASA-European Space Agency campaign in humanity’s first ever Mars sample-return effort.
NEW SPECIES OF CUSTARD APPLE FAMILY FOUND IN MYANMAR -
With over 100 different species, Artabotrys is a large palaeographical genus that belongs to the custard apple family (Annonacea), one of the most diverse and primitive families of the angiosperms. During an expedition to Yinmabin district, researchers from Monya University discovered a new Artabotrys species. It is a climber, up to 2.6 metres tall and was named in honour of Mr. Chit Ko Ko, a Myanmar botanist noted for his botanical research.
MEDIA RECOMMENDATIONS ELEMENTAL: HOW THE PERIODIC TABLE CAN NOW EXPLAIN (NEARLY) EVERYTHING – TIM JAMES Ever wondered how what the most toxic poison ever synthesised is? Or how that would even be calculated as a comparable number? Can human beings really spontaneously combust? The answers to all those questions and a huge array of others can be found in this short, snappy science book. It is fabulously written and actually funny, recounting lots of interesting stories that surrounded and resulted in the formation of the period table as we know it today. This book is great for anyone who loves science, finding out fascinating facts or just wants to expand their general knowledge (I can guarantee reading it will lead to at least one conversation starting with ‘did you know…’). Overall, the book is enjoyable, easy to read and a bit of fun.
THE SEVEN DAUGHTERS OF EVE; THE ASTONISHING STORY THAT REVEALS HOW EACH OF US CAN TRACE OUR GENETIC ANCESTORS -BRYAN SYKES Sykes takes you straight into a genetics lab on the brink of a revelation, then carries you through ground-breaking discoveries. Along the way, detailing how fascinating experiments are carried out including tales of professional rivalries, the hurry to print papers, letters to scientific journals and defending your research. Through this journey, you can discover how mitochondrial DNA can be used reliably to trace ancestry back through an unbroken maternal link, leading to discoveries about the true ancestry of the Polynesians and Europeans. Not too much of a spoiler, as it is in the title, but 95% of Europeans can trace their genetic ancestry back in an unbroken maternal link to one of seven women living tens of thousands of years ago. This book is quite easy to read and genuinely interesting, a great mid-way book into the more intense hard-core scientific books.
QUANTUM: EINSTEIN, BOHR, AND THE GREATE DEBATE ABOUT THE NATURE OF REALITY MANJIT KUMAR A brilliant and exhaustive account of decades of arguments, friendship and rivalry, and serves as a scientific biography of all the greatest names in quantum mechanics: Planck, Einstein, Bohr, Heisenberg, Pauli, Dirac and more. Kumar showcases the battles between Einstein and Bohr in the road to the discovery of the big ideas about quantum theory. It explores the big theories such as the Copenhagen interpretation, wave-particle duality, the Heisenberg’s uncertainty principle and of course, Schrödinger’s famous cat. Quantum is a book for those curious about Quantum theory, but wish to skip over all the mathematics. It is detailed and scientific, but showcases the philosophical controversies in the debates between Einstein and Bohr.