Images of Science

Since July 2022, the James Webb Space Telescope has been delivering images of the universe with unprecedented sharpness. Among these, the so-called "Pillars of Creation," a breathtaking assemblage of gas and dust located within the Eagle Nebula, approximately 6,500 light-years from Earth. Within these structures, new stars are actively forming from the surrounding gas. Two cameras onboard the telescope capture infrared light across various wavelengths, making it possible to see newly born stars shining through the gas and dust. The red regions, particularly at the tips of the pillars, indicate shockwaves as young stars gradually carve out space for themselves.
Key components of the infrared camera systems on the James Webb Telescope were developed and constructed at the Max Planck Institute for Astronomy.

 

In the attosecond physics laboratory of Ferenc Krausz, who was awarded the 2023 Nobel Prize in Physics, special mirrors shimmer in all the colours of the rainbow. Krausz's team uses these "chirped" mirrors to precisely shape laser pulses, enabling the generation of ultra-short flashes of light lasting just a few attoseconds. An attosecond is an incredibly brief moment – one billionth of a billionth of a second (10^-18 seconds).
Crafting such mirrors is a delicate art. They are composed of individual layers of atoms that are specially vapour-deposited. These thin layers allow different colours of light to penetrate the mirror at varying depths before reflecting back. Ultra-short attosecond flashes serve as a universal tool for exploring the microscopic world, as they allow researchers to "photograph" the incredibly fast movements of electrons, study their behaviour, and even control them—whether in gases, blood, or materials used in electronics.    
 

All neutron stars, compact remnants of supernovae, are magnetic. But some of them, even called "magnetars", are the strongest magnets in the entire universe. The reason for their exceptionally strong magnetic field is probably that they are formed in supernova explosions of stars that are already highly magnetic. But how do these get their unusually high attraction? A team of astrophysicists from Germany and Great Britain has now solved this 70-year-old mystery. On the computer, the researchers merged two stars, each of which possessed a normal magnetic field. The picture illustrates this process, the coloration depicts the strength of the magnetic field, the hatching the field lines. The final product of the simulation was a single, but now extremely strong magnetic star. If one day it explodes as a supernova, a magnetar will be born from the debris.
 

They tend to be overshadowed by their far more famous neighbours and for a long time hardly anyone was interested in them. Yet without glial cells nothing in our heads would work at all! Glial cells occur in our brain about as frequently as nerve cells. They form the basic structure of the brain, supply the nerve cells with food and dispose of their waste products. The myelin sheath that electrically insulates the long nerve fibres is also formed by glial cells. It is the prerequisite for the effective nervous system of vertebrates. In the case of an injury - for example after a stroke - certain types of glial cells come into action: microglia (here red) and astrocytes (green) support, protect and nourish the nerve cells (here recognisable as a diagonal band of cell nuclei coloured blue), so that they can regenerate and perform their own functions with optimal support.
 

In a way, this simulation opens a window into another world. Researchers at the Max Planck Institute for the Physics of Complex Systems have calculated how a spin liquid could be detected. According to theoretical considerations, spin fluids should exist, but they have not yet been clearly demonstrated experimentally. In spin liquids, the spins that give each atom a magnetic moment interact strongly with each other, as in a ferromagnet. However, they do not form a fixed order, but move constantly. The Max Planck team has simulated what signature a certain type of spin fluid would leave in neutron scattering (this method can be used to elucidate the magnetic structure of a material). In order to simulate the scattering pattern, the researchers used a model that is mathematically related to the theory of fundamental forces in physics (electromagnetism, for example). However, in our world, their model only applies to spin fluids. In another universe with different physical laws, however, it could describe the effect of the fundamental forces. In this respect, spin liquids provide insights into the physics of possible other worlds.
 

Under the microscope, these crystals look almost like coulorful ice flowers. The "small" difference lies in the temperature: these iridescent structures form when hydroxyquinol cools crystallizes while cooling from a 150 degree hot melt. Max Planck Scientists are investigating the suitability of this benzene derivative as a co-former for a potential pharmaceutical agent: bisdemethoxycurcumin (BDMC), one of the three main ingredients of the turmeric plant. BDMC is considered a potential active ingredient for the prevention of Alzheimer's disease and cancer. However, it is very poorly soluble in water and therefore poorly absorbed by the human body. However, if two chemical substances – in his case hydroxyquinol and BDMC – are crystallized together, co-crystals with new physicochemical properties can form. This way, hydroxyquinol might increase the water solubility and thus the bioavailability of BDMC.
 

About 26,000 light-years from the Sun, a supermassive black hole is lurking deep in the heart of our galaxy. The environment of this object, called Sagittarius A*, offers scientist a unique laboratory for testing the laws of physics in extremely strong gravitational fields. Reinhard Genzel and his team at the Max Planck Institute for Extraterrestrial Physics have been studying the galactic centre for many years. Among other things, their attention is focused on a star called S2, which orbits the mass giant very closely and at high speed. With the measurement of precise orbital survey of S2 the astronomers in 2020 were able to prove a phenomenon that Albert Einstein described in his general theory of relativity: the elliptical orbit of a star does not remain stationary in space, but advances, as it were. Whenever S2 is at the closest point to the black hole, it changes its orbit a little. In this way, its orbits draw the shape of a rosette, as illustrated in the picture.
 

Corona viruses such as SARS-CoV-2 have characteristic protein structures protruding from their surface. The whole virus group even owes its name to these spikes (corona = crown). More important, however, is the crucial role these spike proteins play in the infection: In order to affect a new cell, the virus must dock with it and deliver its genetic information into the cell. First, the spike protein binds to a precisely matching receptor on the cell surface. Only then can the virus fuse with the cell membrane. The spike protein is therefore also an important starting point for the development of vaccines and drugs against Covid-19. Max Planck scientists have discovered that the "stalk" of the spike structure is surprisingly flexible. This might help docking with the target cell.  The chains of sugar molecules (shown in green) that protect the spike proteins from the immune system also "flutter" back and forth and can thus cover a much larger area – similar to a windscreen wiper.
 

Various mechanisms of movement have evolved in nature, including propulsion by tiny hair-like structures. These so-called cilia and flagella perform whip-like movements to enable locomotion. Arrays of ciliated cells with cilia on their surface work together to expel pollutants from our airways, for example. Last but not least, the regular beating pattern of cilia and flagella also propels sperm or microorganisms such as the green alga Chlamydomonas reinhardtii. The picture shows experimental forms of a flagellum isolated from  Chlamydomonas reinhardtii and reactivated with ATP,  the universal storage form for energy in cells. The isolated flagellum, which is about one hundredth of a millimetre in size, begins to oscillate and rotates counterclockwise in the field of view.
 

Many solids are crystals whose atoms or molecules form regular lattices. However, especially in metals, there are often areas where the crystal lattices have different orientations. This affects the electrical and mechanical properties. Materials researchers therefore grow special monocrystals in which the crystal planes are oriented the same everywhere. This picture shows a section through such a vanadium monocrystal. The different colours show areas in which all atoms lie in one plane. However, the differences in height are minimal: the step height is about 0.2 nanometres. The stripes on the coloured terraces are caused by oxygen atoms that migrate to the surface when the crystal is purified. They form a so-called superstructure, which has many defects. Researchers are making a virtue out of necessity: they are investigating precisely such defects, because some of these interact with the vanadium substrate. By comparing these interactions in normal and superconducting substrates, the scientists gain important insights for the development of new superconductors.
 

Even if bones appear sturdy and lifeless at first glance, they are actually consisting of thousands and thousands of living cells and are constantly being built up and rebuilt. This is the reason after all why a fracture can heal. A network of capillaries or smallest blood vessels ensures that the cells are supplied with oxygen and food and that their waste products are disposed of. This network is far more complex than expected. Using new imaging techniques, researchers have identified two very different types of blood vessels: column-shaped capillaries lead directly to a region named metaphysis - the area in the bone where growth takes place in adolescence. They play a key role in skeletal development. Branched capillaries are located in the bone marrow cavity and are associated with hematopoietic stem cells. They are important for the production of new blood corpuscles. The picture shows the complex capillary network in the femur of a three-week-old mouse.
 

Steel is one of the most versatile construction materials ever. Since its properties can be influenced over a wide range by forming, heat treatments, and not least by alloying - i.e. adding different quantities of other elements - tailor-made grades are now available for a wide variety of applications. This image shows the crystallographic structure of a specific version of a stainless steel very often used in the food industry due to its chemical resistance. The material was manufactured by 3D-printing. The colours illustrate the crystal orientations, which have a decisive influence on the properties of the material.
A closer look reveals that our image was created by duplication: The original result was mirrored on the longitudinal axis.
 

In the life of a plant, too, much depends on the right timing – from seed germination to growth and flowering. So plants can measure the length of the day or the temperature in order to switch from the growth phase to the reproduction phase at a suitable time - in other words, to flower. The image shows how the flowers of a thale cress, botanically called Arabidopsis thaliana, develop from the dome-shaped tissue of the shoot tip. The thale cress is a so-called long-day plant that blooms in spring. The plant measures the length of the day via its leaves. If the light period is long enough, messenger substances migrate from the leaves into the shoot tips and transmit the flowering signal. In this way, the plant ensures that the flowers are formed at the right time to ensure fertilisation, seed formation and species conservation.
 

Electric current is physically speaking the movement of electrons through a conductive material. The electrons usually flow in the direction of the force acting on them. This is not the case, however, in so-called topological materials. Here electrons perceive a twisted world; instead of moving straight ahead, they move perpendicular to the applied voltage. In most cases, this special state – the material now behaves like an electrical insulator in its interior, while at the same time having almost resistance-free conductivity at its edges – is created by applying strong magnetic fields. In graphene, a single layer of carbon atoms, this effect could also be induced by circularly polarized light. The picture shows the band structure of the graphene changed by the laser light. The band structure describes the electronic structure of a material and provides information about its properties. As soon as the laser pulse is over, the graphene returns to its original state. This effect could play an important role in the development of new sensors or computers, for example.
 

Knecht Ruprecht, Krampus or Bartl  – wild figures populate the world of legends in many parts of Germany. Looking at this image, you may wonder if one of these scary fellows did fall into the clutches of modern medicine, complete with his bundle of rods. Far from it – but nevertheless, this CT image is very unusual:  it shows the skeleton of a freshwater ray from the Amazon basin, made entirely of cartilage. Unlike human cartilage, the cartilage tissue of sharks and rays is covered with a thin layer of mineralized platelets. These innumerable, small, assembled tiles make the cartilage tissue, which is soft in itself, so firm that it can fulfil the function of bones in the body of the "cartilaginous fish" and, for example, serve as a base for the muscles. And it makes the tissue particularly dense, so that – in contrast to the cartilage in our ears, noses or knees – it is visible in X-rays.
 

Black holes swallow all light, making them invisible. Although they can be detected indirectly - for example by their effect as gravitational lenses - it should be impossible to image a black hole directly. And yet researchers in a worldwide collaboration have now succeeded in photographing a black hole. In arithmetical terms, the telescope required would have to have a diameter close to that of the Earth itself. To get around this limitation, scientists combined eight high-resolution radio telescopes around the globe to form a virtual telescope, known as the Event Horizon Telescope. The signals from the individual antennas were thereby superimposed with nanosecond precision. From the almost unimaginably large amount of measurement data, astronomers finally calculated this image. It shows the particularly supermassive black hole in the centre of M 87, a giant elliptical galaxy in the Virgo cluster of galaxies.
 

Powdery mildew (Golovinomyces orontii), a plant pest from the sac fungi group, forms a filamentous network or mycelium on the leaves of its host plant, in this case the mouse-ear cress (Arabidopsis thaliana). The sporophores, which protrude from the mycelium, develop stacks of spores at their tips, which are spread by the wind. Some Arabidopsis specimens have genes that enable them to defend themselves against the fungus. However, these defence mechanisms cost the plant a lot of energy. Therefore, the resistant plants are smaller and produce fewer offspring. Even in the plant kingdom, there is no such thing as a free lunch!
 

One day, magnetic vortex structures, like the one shown here, could help to process data particularly quickly. These structures arise in magnetic wafers of one micrometre in diameter and just a few nanometres thick. Unlike in a standard permanent magnet, the individual magnetic moments, which can be imagined as tiny rod magnets, order themselves in these wafers: their magnetic field forms needles which project from the front (red) or back (blue) of the disk and can thus store the zero or one of a data bit. Short magnetic pulses flip the needles from one direction to the other with lightening speed. The simulation shows the transition with the needles to the front (red) and back (blue). The magnetic moments in the orange and green areas only project slightly from the image plane.
 

For agriculture, the thale cress (Arabidopsis thaliana) has virtually no significance. And yet it is one of the most famous plants in the world: the small, annual weed is the most important model organism in plant research. It is unpretentious, grows quickly and forms large amounts of seed. Above all, it has already been thoroughly investigated, and its genome, consisting of exactly 25,498 genes - which is rather small for a plant - has been completely sequenced. This image shows an Arabidopsis seedling, which scientists use to investigate the transport of proteins between cells and tissues. The picture shows the first two leaves of the plant; the empty seed coat is lying on the bottom left. The plantlet produces a red fluorescent protein in its epidermal cells; the chloroplasts and plastids are illuminated in blue. In the experiment, the examined protein can only be found in the epidermal cells, which means it will probably not be transported into the cells below.
 

Albert Einstein postulated the existence of gravitational waves in his General Theory of Relativity more than 100 years ago. On September 14, 2015 scientists were able to directly measure them for the first time. In the universe, these tiny distortions in spacetime occur practically all the time. However, even with the most sensitive detectors they are measurable only when very large masses move very quickly – for example when two black holes or two neutron stars collide. Even then, the signals that arrive at Earth are very, very faint. In order to be able to identify them in the vast volumes of detector data, physicists study events in which strong gravitational waves are generated by means of numerical simulations. The picture shows a simulation of exactly that collision of two black holes measured in September 2015.
 

White blood corpuscles play an important role in our immune system. Among these cells, the neutrophil granulocytes – generally referred to as “neutrophils” – form the first line of defence. They literally devour bacteria by surrounding the pathogen and digesting it in their cell interior. The neutrophils (shown here in orange) also have another ingenious trick up their sleeves: they can burst and eject fibrous net-like structures (yellowish green), trap bacteria in them and thereby kill them outside the cell. This image shows Shigella bacteria (blue) being caught in a net cast by neutrophils.
 

All living organisms are made of proteins. The basic structure of these macromolecules - from which, for example, skin, hair or muscles are built - are long chains composed of 23 different amino acids. Their sequence is determined in the genetic material in each and every cell. Chemically, two forms of each amino acid exist, which differ only in their optical rotation. In nature, however, normally only one of these forms can be found, the so-called L-shape. By using LC-PolScope technology, researchers hope to discover why this is the case, and what molecular recognition processes lead to this preference. The growth direction and the optical activity of individual grains in a thin polycrystalline amino acid-polymer hybrid film can be identified through the assignment of different colours. Grains of the same colour have the same growth direction.
 

Researchers hope for higher efficiency in future solar cells. To achieve this, they form the silicon for photovoltaic elements not into today's conventionally smooth layers, but into 'carpets' of nanowires which absorb a lot more light. Since the wires are just 100 nanometres thick and two micrometres long, they resemble tiny towers. Max Planck researchers produce these structures by initially coating a thin layer of silicon with polystyrene spheres. They then remove the silicon, which is not protected by the beads, by etching it with plasma, i.e. strongly ionized gas. Normally, the silicon towers stand close together. Here, researchers have left gaps between the polystyrene spheres to be able to inspect the wires from the side as well. The electron microscope, with which the picture was taken, distinguishes between different materials because it uses two different detectors. It shows polystyrene in red and silicon in green.
 

Those wanting to study the movement of atoms have to be fast: required is a high-speed camera with “shutter speeds” in the femtosecond range, which is one millionth of one billionth of a second (10^-15 s). Researchers have now succeeded in generating electron pulses of just 28 femtoseconds in duration – six times shorter than was previously possible. When these ultrashort pulses meet a biomolecule crystal they are dispersed on it. A characteristic diffraction image like the one shown here is generated for each molecule. In future, physicists want to use these new possibilities to observe particle movements during a reaction. To do this, they excite the molecule with the help of an optical laser pulse and follow this with an electron pulse to capture the momentary structure. An extremely large number of such snapshots in series result in a film of the atomic dynamics.
 

It forms clouds, causes storms – and presents considerable challenges for climate researchers: turbulence forms in the atmosphere when warm and cold air come together. For example, if a city heats up considerably more than its surroundings in summer, the warm air rises rapidly, like in a chimney. Along the edges, it mixes with the colder ambient air in numerous large and small vortices. Particularly interesting situations arise when the rising plumes of heat from two or more sources of heat interact. The likelihood then increases that they will churn up the atmospheric layering of an entire region and eventually influence the climate. Scientists use computer simulations to vary the magnitude of the heat sources and their distance from each other.
 

Spherical lenses are widely used in research, for example as front lenses in microscope objectives. A special kind of such lenses are solid immersion lenses (SIL), hemispherical lenses made of material with a particularly high refractive index. These lenses play an important role in many areas of physics, biology and medicine today, as very high spatial resolution can be attained with their help. The image shows an SIL, the surface of which is being measured in a Twyman-Green interferometer for the purpose of quality assessment. The lens consists of gallium phosphide (GaP), a material that is transparent for light of certain wavelengths and has a very high refractive index. By this means, the light focusing required for high-resolution tests can be attained.

The SIL in the photograph appears to hover in the air as a sphere; however, this impression is misleading: the hemispherical lens and the objective of the interferometer are reflected in the object slide, a metal mirror, on which the lens is placed.
 

Whether corals, worms or mussels: Many marine invertebrates begin their lives as part of the plankton. This is also the case with the annelid or ragworm Platynereis dumerilii, which has become an important model organism in evolutionary developmental biology in recent years. The larva controls its movement with the help of a prominent, regularly beating belt consisting of thousands of tiny hairs or cilia. But how does it find a place that can offer the adult worm ideal conditions for its rather stationary existence? A simple organ at the head end of the larva, known as the apical organ, plays a crucial role. Neurons located here perceive environmental stimuli and produce a neuropeptide in response, which alters the beat of the cilia. The larvae start to sink, and then crawl along, surveying the sea floor. They can presumably detect food in this way, and thereby find a suitable habitat.
 

Methane is over 20 times stronger in its effect as a greenhouse gas than carbon dioxide. It is formed when certain bacteria from the Archaea group decompose organic material under the exclusion of air – for example, in rice fields, bogs and cows’ stomachs. The enzyme Frh, a hydrogenase, plays a key role in the process: it splits hydrogen, which can then react with carbon dioxide to form the methane. The Frh protein consists of a total of twelve trimers, each of which has three subunits, here in blue green and purple. It contains several iron-sulphur clusters – shown as yellow structures in the image – and nickel and iron in the active centres, where the reaction takes place. The structure and function of this enzyme are not only of interest to climate researchers: the molecule could provide a model for the development of catalysts for hydrogen production.
 

The giant asteroid Vesta is a relic from the stormy youth of our solar system. At that time, more than four billion years ago, there were no major planets yet. Small pieces of debris clumped together and formed into protoplanets, which in turn grew into planets. Vesta, which is about 525 km in diameter, appears to be such a protoplanet, perhaps the last example of its kind. This interpretation is also supported by the measurements of Nasa's Dawn spacecraft. The false-colour image helps us to engage in geological field research. The topographic map was constructed from more than 17,000 individual images taken by the framing camera of Dawn, whose camera eyes were equipped with varying filters. The different colours indicate different highs and lows: purple denotes 22.5 kilometres below the surface; white 19.5 kilometres above the surface. Vesta's densely cratered landscape - evidence of earlier collisions with other celestial bodies – also features high mountains and is surprisingly heterogeneous. It looks more like a terrestrial planet than a primitive asteroid.
 

What looks like an exotic flower at first glance, is, in fact, the human immune system in action: a white blood corpuscle (shown here in red) is in the process of disarming tuberculosis bacteria (yellow). The pathogens are encircled by the scavenger cell membrane, pulled into the interior of the cell and locked in there – ideally forever. However, Mycobacterium tuberculosis is an extremely tough customer: thanks to a particularly resistant membrane, the bacteria can survive for many years inside the scavenger cells and may be released again if the host immune system is weakened, for example through diseases like AIDS or the effects of ageing.
 

Although humans and zebra fish appear to have little in common at a first glance, an astonishing number of parallels can be observed in their development and the structure of their organs. For example, the retina of the eyes in both species is structured very similarly. For this reason, the small fish is a popular model organism for studying the development of our visual organ. The image shows a cross-section of the retina of a three-day-old zebrafish embryo. The researchers made different cell types visible using fluorescent proteins. This enables them to trace the way in which the cells rearrange themselves while the initially simple tissue layer develops into a multi-layered structure. Part of the cell skeleton can be seen here in green, and the cell walls of the photoreceptors and the optic nerve, which conveys information to the brain, are bright pink.
 

What is 17 multiplied by 146? Or 111 plus 97? Complex cognitive skills such as calculation wouldn't be possible without complicated connections of neuronal circuits in various brain regions. With the help of diffusion-weighted magnetic resonance imaging (MRI), neuroscientists are able to uncover how these nerve fibre bundles connect different regions of the brain. To this end, the scientists use the natural magnetism of the particles in the brain in order to measure the diffusion movement of water molecules in the tissue. This enables them to draw conclusions on the pathways and signal orientation of the large nerve fibre bundles. The researchers translate the measured diffusion gradients into bright colour patterns, with the colours corresponding to the direction of the fibres (red: left-right; green: front-back; blue: top-bottom).
 

Chaos often arises when non-linear processes unfold. The minutest changes can have major impacts, as in the case of the climate, for example. In this simulation, however, a non-linear interaction has a more ordering effect: a very intensive flash of ultraviolet light lasting just 100 femtoseconds – one femtosecond corresponds to the millionth of a billionth of a second – runs from left to right through the noble gas xenon. After a time a soliton – a type of super light pulse that is stabilised by non-linear processes – splits from the light pulse, which can be seen in yellow on the left-hand edge of the image. Unlike normal light or water waves, solitons do not dissolve. The merely 15-femtosecond soliton can be identified as the sharp line, the most intensive areas of which are red.
 

Learning and memory are based on the constant modification, dismantling and re-establishment of the connections between cells in the brain. Simplified models are needed to enable scientists to study and understand these complex processes. Researchers at the Max Planck Institute for Brain Research grow neurons in fine microchannels on plates with a photolithographic structure. In this way, the complex three-dimensional network of neurons in the brain is reduced to two dimensions in the cell culture. The researchers can thus analyse how the synapses between the cells form or dissolve, and examine the role played by substances like neurotransmitters in these processes. This cell culture technology is also of great interest for the development of new active pharmaceutical substances.
 

Precious feathers were much prized in Pre-Columbian Central America; they played an important role as tribute, as cult offerings and as part of rulers' regalia. The feather mosaics of early colonial Mexico link this tradition with European figurative culture. Made of the finest feather fragments, they represent Christian motifs derived from European prints imported for missionary purposes. In turn, the feather icons were brought back to Europe as diplomatic gifts – shimmering testimonies of the early encounter between the arts of the Old and New Worlds. Here exotic humming bird feathers are used to represent heaven in a picture of the Evangelist John. The poor conservation is also evident: insect damage threatens the iridescent colours.
 

The zebra fish (Danio rerio), a striped fish around five centimetres long, has similar heart genes to those of human beings. The signalling pathways that control the organ’s formation also match to a large extent. This small animal is thus a popular model organism. Scientists suppress the formation of specific signalling proteins and observe the effects on organ development. The image shows a normally developed heart of a 48-hour-old zebra fish embryo, dyed using fluorescent proteins. At this point, the heart measures only half a millimetre and – as in all fish – consists of an atrium and a ventricle. The heart muscle cells are highlighted in green, and the cell nuclei in red. The atrial myosin – a protein that only exists in the atrium – glows blue.
 

Dark matter is not visible, it does not emit any kind of radiation, yet is exists! Its gravitation attracts other, ordinary matter. To better understand the structure of the universe, scientists use extremely complex computer simulations: Here researchers fed a supercomputer with data from the initial state of the cosmos to then simulate the evolution of the universe. In a computing time of about two months, a cube-shaped section of the universe with an edge length of approximately one billion light years was created. It shows the large-scale structure of the universe as a blue web of gas and stars. This luminous network reflects the underlying backbone of the dark matter shown in yellow and white, which makes up around a quarter of space.

The flow of liquids or gases plays a very important role in many technical processes, also economically, for example, in the development of vehicles with lower fuel consumption. To describe the characteristics of a flow, researchers analyse the movement of the individual particles. An important feature here is the so-called streak line, which arises from a multitude of particles that are introduced successively into the flow from the same location. This process is easy to research in the laboratory using smoke, which is blown continually from a nozzle and moves with the flow. To date, it has not been very easy to simulate this in a computer-based visualisation. However, thanks to a new mathematical approach, it is now possible to describe streak lines by means of standard differential equations and compute their characteristics much faster. The streak lines in this image were calculated in less than one minute using the new process; it would take over two hours using the classical algorithm.
 

Numerous proteins interact with the cell envelope. They fulfil a wide range of tasks - from signal processing to cell division. Due to the extreme complexity of these processes, scientists at the Max Planck Institute of Biochemistry use an approach known as minimal systems. In these minute, synthetically generated systems, they can observe selected cell components and their functions under controlled laboratory conditions – like the lipid membrane shown here with accumulated proteins. Because these proteins move and organise themselves independently in the membrane, they form movement patterns that look like a wave carpet. The researchers observe these structures as an interplay of purple shapes and forms.
 

Although it was already in use in ancient China, cast iron is to this day a popular subject of current basic research. As an alloy with spheroidal graphite, it is as malleable as steel, but significantly less complicated and less expensive to produce. Also known as spheroidal iron, it is used for the production of pipes, in the automotive industry or in reactor technology, for example. The image shows the microstructure of the alloy: the spherical nodules of carbon appear as round islets; the fine network of lines indicates where different grains of materials collide. Max Planck researchers are studying the effect of this microstructure on material properties. They would like to be able to tailor the structure and thus the properties of the material to different applications.
 

Standing on a shell, the sea god Neptune steers a team of horses through the waters. This scene is captured in an extraordinary mosaic in the Fonte Doria in Genoa. The artificial grotto – which was constructed by the architect Galeazzo Alessi in the mid-16th century – has several fountains and is decorated with coral, shells, majolica tiles and crystals. Due to its extremely poor conservation status, the Fonte Doria is no longer accessible to the public. The mosaics were surveyed and documented as part of a photographic campaign by the photo library of the Kunsthistorisches Institut in Florenz. Each year, the KHI photo campaign produces around 3,000 digital images of the interiors of Florentine palaces and villas – which are still relatively poorly researched – and of the art and architecture in smaller centres in Tuscany.
 

Pharmaceutical substances are most effective and cause fewest side effects when they are released directly in the diseased area of the body. Max Planck scientists are working on the development of a drug delivery system that only releases drugs when it recognises the target cells: microcapsules with special recognition molecules dock directly onto diseased cells, e.g. cancer cells. The drugs can escape through the capsule walls as a result of changes in the temperature, pH value or salt content. The image shows different types of such capsules that were exposed to different temperatures: some shrivelled to form solid balls (yellow) and others melted to form bigger capsules (green), which collapsed when they dried out.
 

Plasma at temperatures of several thousand degrees rises from the Sun's interior, cools and sinks back down to the depths. Wherever strong magnetic fields restrain the plasma, dark sunspots appear. On the edges of the spot shown, thread-like structures are visible. The magnetic fields in these regions should actually be strong enough to prevent currents – they should therefore appear darker. However, scientists at the Max Planck Institute for Solar System Research have been able to prove that the magnetic fields here have loosened in some places. In these regions, elongated bright structures form, in which high-energy plasma can reach the surface despite high field strengths.
 

In modern layered semiconductors, the electrons in the interface area between two neighboring semiconductor layers are almost unrestricted in their movement. An externally applied magnetic field focuses electrons escaping from a point contact onto a second point contact (lower half of the simulation). If impurity atoms, for example phosphorous atoms, are introduced into the semiconductor to increase conductivity, the extremely weak electrical fields of these doping atoms already generate random minimal deflections of the electrons. This results in the formation of additional focusing lines, which give rise to a highly characteristic ramification of the current density (upper half of simulation). Very similar mechanisms in oceans can result in monster waves that appear to come ‘out of nowhere’.
 

Even when fully grown, the zebrafish (Danio rerio) is only about five centimetres long. The small fish is a popular model organism in developmental biology. Many of its genes and a great number of the signaling pathways that control the formation of tissues and organs are identical or similar to those of humans. And another important aspect for research: the fish are easy to maintain and develop very rapidly. In just three months, a fertilised zebrafish egg cell grows into a sexually mature animal. This image shows two-day-old larvae; the mouth opening is already clearly visible. What at first glance appear to be the eyes of the larvae, however, are actually apertures surrounded by cilia – the organisms’ future olfactory organs.
 

Fusion power plants are supposed to harness energy from the fusion of atomic nuclei, in a similar way to the sun. The fusion fuel, an ultra-thin hydrogen plasma, has an ignition temperature of over 100 million degrees Celsius. Even the vessel walls reach temperatures of a few hundred degrees. Researchers therefore have to develop heat-resistant materials for the construction of such plants. The sample shows a wolfram alloy, into which silicon and chrome have been incorporated to make the material oxidation-resistant. Under the microscope, stress cracks can be seen. These are caused by the different rates of thermal expansion - an effect that should be avoided during subsequent application.
 

Solar cells provide a climate-friendly energy supply. To ensure that solar cells increase their efficiency in converting sunlight into electricity and require smaller amounts of silicon in the future, scientists are researching photovoltaic elements that do not consist of a closed silicon layer, but a thin 'carpet' of nanowires. Usually, the silicon wires are very close together. On the one hand, the light is trapped between the columns, hall-of-mirrors style; on the other hand, the nanowires have special optical properties that allow them to absorb more light than a smooth layer. Aesthetically, however, isolated nanowires are far more pleasing - especially when they are scanned with an electron beam that is captured by three diodes which show the scattered electrons in red, green or blue, respectively. This colour display is created when one or two of the diodes are in the shade, cast by the electron beam on a nanowire.
 

Turbulent currents play an important role in climate events, for example in cloud formation or – as calculated and visualised here – in the exchange processes that occur on the surface of water bodies. When the water on the boundary with the air cools down, through convection and uplift, a typical cell-like pattern of the heat distribution in the water arises in the layer underneath. The dark zones in the image are relatively warm areas, which move upwards while cooler areas, often just a few millimetres wide, move down – the light-coloured edges of the “cells” here. Tiny whirlpools arise at the network nodes, sometimes even double vortices with opposite directions of rotation.
 

The Neisseria bacteria shown here are just one thousandth of a millimetre in size. These pathogens, which are also known as gonococci, cause the sexually transmitted disease gonorrhoea. In the early stages of an infection, they accumulate in sets of two and four at the cells of human mucous membranes. This detailed image clearly shows how the bacteria succeed in being absorbed by the mucous membrane cells: the cell membrane has already closed around some of the gonococci. This marks the beginning of the infection, which can result in inflammation and copious pus discharge.
 

Powdery mildew (Golovinomyces orontii), a plant pest from the sac fungi group, forms a thread-like mass or mycelium on the leaves of the thale cress (Arabidopsis thaliana). The sporophores which protrude from the mycelium develop stacks of asexual spores at their tips which are spread by the wind. This way, the fungus can infest other plants. Scientists use the interaction between powdery mildew and the thale cress as a model system for studying how plants react to fungal infestations and how the fungi deal with the plant’s defence mechanisms.