Tabla de contenidos para Issue 47 en Science Illustrated

Scientists have not yet come up with a complete answer to explain female orgasm. Male orgasm is necessary to expel sperm, but women can fall pregnant without orgasm. One theory is that it encourages the female to keep the male around, as humans are vulnerable during early child rearing. PHASE 1 AROUSAL When a woman becomes sexually aroused, the afflux of blood to her genital organs increases. The blood vessels expand, and her clitoris and labia swell. Duration: From a few minutes to several hours. PHASE 2 PLATEAU Powerful afflux of blood makes the moist vagina walls swell and become solid, ready to receive the penis. The clitoris becomes so sensitive that it retreats to avoid direct stimulation. Duration: Several minutes. PHASE 3 ORGASM Rhythmic contractions in and around the…

When two electrodes are separated by a glass plate, a spark between them will travel around the glass, as the air molecules conduct the flow of electrons. 1 The electric voltage difference between a negative and a positive electrode increases. 2 At some point, the voltage difference becomes high enough to ionise gas molecules between the electrodes. The molecules' electric resistance is considerably reduced. 3 The gas molecules enter into a higher energy state, when they are hit by electrons between the electrodes. Energy is released in the form of light, when the molecules return to their basic energy state.…

Lunar rover paved the way While the astronauts of the first three Apollo missions could only walk and jump about close to the lander, the last three missions to the Moon could move about in the weak gravitational field on four wheels. Apollo 15, 16, and 17 brought individual versions of the LRV (Lunar Roving Vehicle), which was the first vehicle on another heavenly body. In order to make room for the extra cargo under the landing module, the rover and its two sets of wheels were folded at the centre . The ”package” as a whole took up about 1m3. On the rover’s first mission, Apollo 15, astronauts Dave Scott and Jim Irwin covered 25 km – almost four times as far as in connection with the previous…

Starlings generally breed in large groups, but outside the breeding season, the team spirit becomes extreme. In the late summer, some one million starlings from the entire Baltic region and Norway get together in south-western Jutland. The biological explanation of the huge flocks is simple – high numbers make up an efficient defence against particularly birds of prey. If a lonely starling encounters a merlin, it does not stand a chance of escaping, but if the merlin faces a huge flock of birds, it is difficult for it to focus on its prey, reducing the risk of the individual starling considerably. On the other hand, scientists have found it hard to understand how the motions of a group of starlings are controlled and why the birds to not collide…

Desert locusts live in desert-like regions, where food is scarce. Consequently, the locusts mostly keep to themselves, as too many peers would make it difficult to find enough food. In most desert regions, it rains sometimes, and the rain can trigger a cascade of events. The locusts suddenly go from being reserved loners to becoming extremely sociable. They breed drastically, and soon, they have consumed every bit of vegetation in the areas in which they live. In order to find more food, the locusts need to migrate. They take flight and convert themselves into huge swarms known as “the 8th plague of Egypt” in the Bible. A swarm can cover an area of more than 1,000 km2 with a density of 40-80 million locusts per km2. Everything is consumed…

TOKAMAK Simple. Symmetrical. Hopelessly Impractical? PROS: The tokamak reactorer is the most simple design. It is easier to build a large fusion power plant with this type of reactor. CONS: As the magnetic coils are located closer to each other on the inside than on the outside, the ring is weaker on the outside. So far, hydrogen can only be kept contained for a few seconds. STELLERATOR Sophisticated. Stable. Maybe Impossible? PROS: In a stellarator, twisted magnets make sure that the fuel is affected by the exact same field strength from all sides. Theoretically, it can be kept stable for months. CONS: Stellarators are extremely complex plants that make up a huge engineering challenge. Consequently, they pose a considerable technical challenge. On 3 February, German Chancellor Angela Merkel hit the…

SOLAR POWER Huge solar power plants can now supply millions of people with power – even after dark. SOLAR CELLS Scientists are developing a new wonder material that can make solar cells much more efficient SOLAR POWER IN SPACE Engineers aim to build solar power plants in space and send the energy back to Earth with microwaves On the Western outskirts of the Sahara, a shadow has appeared in the desert, which is usually a very hot place. In an area of 450+ hectares in the Quarzazate region of Morocco, 500,000 arched mirrors are aimed at the Sun. Instead of the heat being wasted in the sand, the mirrors capture the sunlight, converting it into power that is used in thousands of Moroccan homes. Sunlight includes so much energy that…

Above the clouds, there is sunlight all day long, and so, French scientist Jean-François Guillemoles proposes to place solar panels at an altitude of 20 km by means of balloons. The balloon power plants would be able to supply power day and night. During the day, some of the power generated by the solar cells will be used to split water into oxygen and hydrogen, which is stored inside the balloon. During the night, fuel cells can generate electricity by converting the hydrogen gases back into water. The power is sent to consumers on Earth via cables integrated into the balloon mooring lines.…

SUDBURY NEUTRINO OBSERVATORY Ontario, Canada. The detector was built 2,100 m below Earth’s surface to keep out distracting radiation. They exist one moment, but are gone the next. For more than 30 years, the neutrinos of the Sun caused scientists to frown, until a neutrino detector deep below the ground in Canada gave them the answer. The neutrinos never disappeared. Instead, they turned into other types of neutrinos that physicists’ old detectors could not identify. New sensors and a tank with heavy water molecules allowed the Canadian physicists to measure the new particles, and the results showed that one single neutrino can switch between three different variants: electron, muon, and tau particles. The solution of the mystery earned the scientists behind the discovery a Nobel Prize, but the results…

Injected into the brain stem every two wee 1 STEM CELLS Produce new building blocks for regeneration In order to recreate damaged areas of the brain, it is necessary to add new nerve cells. Doctors do so in the shape of stem cells – a type of cells which can develop into any type of body cell, from liver cells to skin cells. Daily injections into the spinal cord over a period of six weeks 2 PEPTIDES Convert supporting cells into nerve cells Less than half of all brain cells are nerve cells, which can send signals and cause brain activity. The majority of the cells are glial cells, which support the nerve cells, providing them with oxygen and energy and removing dead cells. A few minutes of radiation per…

PUT YOUR KNOWLEDGE TO THE TEST 1. Which Order of vertebrates are unique for having their pelvis inside their enlarged and specialised rib-cage? 2. Which country was the first to land a probe (well, crash really) on Mars back in 1971? 3. What mineral, used in power generation and the production of germanium, has the proper geological name ”lignite”? 4. What destroyed a Minoan settlement and inspired many apocalyptic Greek myths sometime in the period 1642-1540 BCE? 5. Is there a scientific difference between shrimps and prawns? 6. What happens when you electrify a two-lead semiconductor in a p-n junction diode? 7. What do traditional Japanese carpenters never use when constructing a wooden house? 8. According to legend, what did the Chinese emperor Shennong accidentally invent in about 2737 BCE,…

A vast mirror to unlock the secrets of the universe Engineers inspect the gold-plated primary mirror one final time, before the James Webb space telescope is turned to install the instruments on the other side. The telescope is on track to launch in 2018. Its primary mirror is six times larger than the Hubble telescope’s, and will capture more infrared light, so we can peer further back in time and space. Expansion of the cosmos causes light waves from the most remote galaxies to stretch on their long voyage to Earth in a process called "redshift", and they are only observed as infrared light. Decay and bitter cold create strange beauty On the floor of Lake Abraham, Canada, bacteria feast on dead animals and plants. The organic material is the…

TECHNOLOGY From 2017, when US Navy divers go on missions in the abyss, they will be wearing high-tech helmets that make other diving helmets seem out-dated. A transparent display is integrated into the helmet’s “windscreen”, adding an extra layer to everything by means of augmented reality. The head-up display (HUD) is highresolution and located directly in the field of vision, so the diver needs not look the other way to check instruments, read messages, or inspect navigation instructions. All sorts of useful information about the surroundings such as sonar images, charts, videos, maps, and task specifications are available to the diver, who can activate or deactivate the display as he or she pleases. The display can also change position and be moved up or down. The intention is that…

_ZOOLOGY When electric eels feel threatened, they may jump out of the water and attack by using a series of shocks. Until recently, scientists thought that the eel only ever attacked underwater. The scientist behind the discovery is Kenneth Catania from Vanderbilt University who researches electric eels and keeps the fish in large tanks. Intending to move the fish from one tank to another, he put his net into the water, and the eels jumped out, pressed against the net handle, and gave shocks. Later, experiments with a plastic crocodile confirmed the discovery. Jumping means worse shocks An adult eel can give a shock of up to 650 volts to paralyse its prey. When the shock is given above water, the concentration is increased, and the shock is even…

Our third eyelid shrank as our eyes evolved "whites" to aid in communication and showing emotion. When I watch my dog fall half-asleep, it looks like she has a third eyelid that comes from the side. Does she really? Many animals have a third eyelid: the nictitating membrane, which typically provides extra protection. The membrane exists in many other animals such as cats and sharks, but not in most primates (except lemurs). Other animals have "custom" eyelids, such as tropical frogs, which have eyelids with camouflage-like patterns. The lids allow the frogs to close their eyes to hide their often very colourful and striking eyes, still knowing what is going on in the world around them. According to scientists, humans also have the remnants of a nictitating membrane in…

LANDING The Martian atmosphere is a little too thin to slow down crafts by means of an ordinary parachute. Moreover, it is thick enough to crush a spacecraft passing into it at a speed of 20,000+ km/h. So, landing on Mars is much more complicated than on the Moon. Gravity: 38 % of Earth’s Average distance to Earth: 225 million km Approximate travel time: 6-8 months Atmosphere: About 1/100 of Earth’s Magnetic field: Very weak Compared to the challenges of Mars, the lunar landings were quite easy. The Moon’s very weak gravitational field combined with the lack of atmosphere mean that crafts can take off again without very much fuel. So, it was possible to get the lunar astronauts back to Earth again. Gravity: 17 % of Earth’s Average distance…

Huge dust storms threaten astronauts’ equipment About every five years, Mars is ravaged by huge dust storms that embrace the entire planet. But although science fiction books often describe the weather on Mars in apocalyptic terms, NASA’s observations show that wind speeds never exceed 100 km/h. In comparison, Hurricane Katrina in 2005 involved wind gusts of 270+ km/h. And as the Martian atmosphere is abut 100 times thinner than Earth’s, Mars storms require much higher wind speeds than on Earth to be just as devastating. Nevertheless, dust storms make up a challenge to future Mars dwellers. The dust could get stuck in moving parts and cause problems. A prolonged dust storm blocks out the sunlight for weeks, and the fine and electrostatic Martian dust could settle on the…

The large African herbivores benefit from each other across species. Wildebeest, zebra, and gazelle graze together in huge groups, improving the protection against predators such as lions. However, the crowding together involves the disadvantage that food in a specific area is quickly consumed. When the grass plains have been ”harvested”, the animals have to migrate to new places to find more food. Every year, rain on the savannas of East Africa triggers the world’s most extensive mass migration of large mammals. Some two million wildebeests, 500,000 gazelles, 250,000 zebras, and 250,000 other antelopes migrate more than 800 km in search of new grass. And as they go along, the animals have offspring, find new mates, and mate again.…

1 Fuel Half the fusion fuel is heavy hydrogen with 1 proton and 1 neutron in the atomic nucleus. The other half is super-heavy hydrogen with 1 proton and 2 neutrons in the nucleus. 2 Process A high temperature of 100-200 million degrees forces the hydrogen atoms so close together that they fuse into helium. 3 Result The fusion releases 1 neutron and high-energy radiation, which is converted into heat and power in turbines.…

ARCHED MIRRORS: A SIMPLE, THOROUGHLY TESTED METHOD Arched mirror plants are the most thoroughly tested technology. The mirrors follow the Sun across the sky, focusing the sunlight onto a pipe at the centre of the arch, in which oil is heated to a temperature of 400 degrees. The heat is used to power a steam turbine and for power storage. HIGH TEMPERATURES MAKE TOWER PLANTS EFFICIENT Thousands of mirrors focus the sunlight onto a container at the top of a tower, heating a liquid to a temperature of 1,000 degrees, making power generation more efficient. Tower plants are more expensive, as the mirrors need to rotate east and west plus up and down to follow the Sun. HUGE REFLECTOR DISHES ARE THE MOST ENERGY-EFFICIENT The most recently developed type of…

ICECUBE NEUTRINO OBSERVATORY The South Pole, Antarctica. The detector consists of 86 strings lined with 5,160 light sensors which stretch 2.5 km into the ice. Every day, Earth is bombarded from outer space, and only the planet’s atmosphere and magnetic field protect us from lethal radiation. Some of the particles may come from supernovas, but even exploding stars cannot produce the most high-energy particles that hit with the force of a brick falling from a skyscraper. Physicists have not been able to do anything but guess where the particles come from. Perhaps they are produced in supermassive black holes at the centre of galaxies or in collisions between collapsed stars. So far, scientists have been unable to measure the direction from which the particles come, as the particles’ electric charges…

Drones cooperate by means of audio signals Even over short distances underwater, a radio signal attenuates down to nothing. To solve this, the autonomous drones communicate in the same way as whales – via sound. With simple modems, drone computers can translate acoustic messages from “colleagues” into digital data and coordinate an ocean floor search all by themselves MODEMS HELP COMPUTERS UNDERSTAND SOUND The word modem is a a combination of “MOdulator” and “DEModulator”. A modem at the sender first converts (modulates) digital data into an analogue signal such as sound. The sound can now be sent to the receiver’s modem via seawater, a phone connection, or even light. The receiver’s modem converts the analogue signal back (demodulates) into its original digital form. Asearch has been initiated on the Atlantic…

It is often difficult for doctors to predict if a patient will wake up after severe brain injury. Scientists have scanned the brains of 131 patients in a coma-like condition, observing the patients’ development and whether they woke up within a year. Brain activity can be measured by observing the use of the glucose sugar molecule, which is the only nutrient that brain neurons can feed on. The more they consume, the higher the activity. The results showed that if a patient exhibits less than 42 % of normal brain activity, the likelihood of them waking up is very limited. It is the first time that scientists have obtained an accurate measure of a coma patient’s chances of waking up. THREE STAGES OF PERMANENT UNCONSCIOUSNESS In everyday language, the word…

Australia’s tea trees - plants in the genus Leptospermum - are almost entirely unique to our arid continent. A few species exist in New Zealand, Southeast Asia, Malaysia and Indonesia, but the bulk of the 87 described species are found only here. Leptospermum means “fine seeded” but the plant’s common name comes from the early settlers throwing a few leaves in the pot to make a sort of bush tea. Leptospermum leaves are high in vitamin C, but they also provide the source of our famous “Manuka honey” which some people believe has special antibacterial properties (tests are inconclusive, though research goes on). This Leptospermum sp. was photographed high up in the Blue Mountains where the plant had grown into a tough little shrub on an exposed plateau. And then,…

ASTRONOMY A huge wall of muddy red water suddenly rises to skyscraper altitude, thundering toward land with the speed of a jet plane. Could this have happened on Mars 3.4 billion years ago? Scientists from NASA’s Ames Research Centre in California, USA, and the Planetary Science Institute in Arizona, USA think evidence points to yes. The rolling monster waves carried huge, 10-m boulders along, and when the water retreated back into the ocean, the water cut 20-km-long and 200-m wide channels in the landscape. New satellite photos of the northern plains of Mars have put scientists on track of the violent events that probably happened approximately one billion years after the formation of our Solar System. At that point in time, the Red Planet was probably both wet and much…

The wind needs both time and space to generate waves. Those conditions only exist in open water, and so, you will always see the waves move towards you. On very still days, and in very sheltered bays, there can be no waves at all. Waves form slowly, as the friction between air and water is only slight. The transfer of energy takes place, as air presses against the front of a wave, sucking at its back. Physicists have accurate formulas describing how large waves can grow. Generally, waves increase in height the more windy it is, the longer it is windy, and the longer the distance affected by wind. That last factor is known as “the free stretch”. In open sea, in areas where the wind is generally high…

Gaffer tape comes with different degrees of adhesiveness, but according to the 3M company, the tape typically has an adhesiveness of 502 g/cm width, when the tape is used on a steel surface. If a piece of 5-cm-wide gaffer tape is used on a steel plate, you must subject the tape to a load of more than 2.5 kg to make it lose its grip. Gaffer tape also works in space, where astronauts participating in lunar missions and other projects have attached tools and repaired spacecraft with the adhesive tape. 3 GAFFER TAPE LAYERS Tape: Gaffer tape is made of water-repellent polyethylene – the most common type of plastic – placed on top of heavy-duty canvas. Glue: The subsurface of the tape includes glue based on natural rubber. Resistance: Gaffer…

Theoretically, microorganisms can survive a journey through space, but it is highly unlikely that a meteorite includes hazardous bacteria. Scientists have never discovered life in meteorites, only complex molecules known as amino acids. The amino acids can function as building blocks of biological molecules such as proteins, which are necessary for all life. But not alive themselves. Every day, Earth is bombarded with more than 100 tonnes of dust and tiny particles from space. A meteorite is a fragment of an asteroid, which has survived the passage through Earth's atmosphere, and landed on the surface. The world's longest snake was recently discovered by construction workers in Malaysia. The huge python is eight metres long and weighs approximately 250 kg…

The first Martians are ready to put on their spacesuits and set up camp in the red dust. Only one last obstacle remains before the settlers can land. No government space agency has a spacecraft that can land a manned capsule on Mars, but a private company has one in the pipeline OPE RATIO N MAR S The question is no longer whether we are going to send people to Mars, but rather when. Probes have mapped out the planet, astronauts are preparing to go, and we have the technology. LANDING The first settlers arrive to a hostile planet, and depend entirely on their equipment MISSION QUESTIONS How is heavy cargo landed? Can the spacecraft endure the mission? What will the Martian suit be like? How to build living quarters?…

Robots excavate foundations 1 The parachute detaches, and the landing module lands, protected by airbags. By emptying some airbags and inflating others, the module rolls to a suitable site. The first robots excavate the foundations. Living quarters roll in position 2 Like the robots, the three living quarter modules land by parachute and airbag. The modules roll to the construction site and place themselves on the foundations. Each module has 12 pentagonal surfaces. The base is inflated 3 The pentagonal panels around the living quarter modules unfold, and the insides of the modules are inflated. The individual modules are linked by air locks. The total indoor area of the base is 93 square metres. Martian dust blocks out radiation 4 A team of robots harvest regolith – the top, loose…

1938 German physicist Hans Bethe proves that energy inside the Sun other stars is generated fusion of hydrogen atoms into helium. 1951 Experiments begin in the world's largest fusion reactor – a stellarator – the US Princeton University. The aim is peaceful use of hydrogen fusion for energy. 1956 The world's first tokamak designed by physicist Andrei Sakharov built in Moscow. In the 1960s, tokamaks produce the best results and become leading. 1997 The European test reactor JET – a tokamak – sets a fusion energy world record by generating 16 MW in five seconds. 2010 The construction of ITER begins in France. The huge tokamak will generate 10-30 times more energy than used to trigger the initial fusion processes. 2016 In the world's biggest stellarator, Wendelstein X in Germany,…

Will laws of physics be rewritten? DAYA BAY REACTOR NEUTRINO EXPERIMENT Daya Bay, China. Three 100 t detectors have been placed around six nuclear reactors, which produce large quantities of neutrinos. In the Daya Bay, China, scientists have found errors in very basic physics formulas. The scientists have used 3 large detectors to measure the flow of neutrinos produced by a nuclear power plant. The result is the most accurate measurements so far of the energy of neutrinos and a count of the number of neutrinos at different energy levels. However, the results differ by about 10 % from the numbers predicted by existing models. But although scientists cannot explain the major deviation, the groundbreaking measurements help them fine-tune their calculations. New, improved formulas will ensure that physicists can come…

SHIP Geneva, Switzerland. A 400+-m-long tunnel must be built to make room for the large new detector. The galaxies of the universe rotate so fast that they would be torn apart if they were not held together by mysterious dark matter. In spite of decades of search, physicists have been unable to detect the dark matter, but the world’s largest physics lab, CERN, intends to change that. The European scientists are preparing a groundbreaking new experiment that could reveal the universe’s last hidden particles. Their detector can measure if one of the three known types of leptons switches into a fourth unknown particle, but it will also be able to detect new particles that are not leptons. The huge device, which has been named SHiP, will be finished…

At this point in time, no standards for underwater communication exist, so two sea drones from two different makers cannot communicate. The aim of the extensive Project Sunrise is to standardise the makers’ software and hardware, so the drones speak the same language. In the end, the aim is to create common standards, so data transmission works, no matter the units that communicate, and no matter if the signal is sent via audio, light, or radio waves. Since 2013, scientists have been working on the project, which is directed by the University of Rome “La Sapienza”. 13 research institutions from all over the world participate. DRONES PROTECT SEA FLOOR DISCOVERIES Professor Chiara Petrioli, PhD in computer engineering, University of Rome “La Sapienza”, heads Project Sunrise. What can the project results…

It is a small miracle that Asbjørn has left home to live in his own flat. Six years ago, when he was 16 and went to high school, he suffered an acute hypoglycaemic event related to his diabetes, and sank into a comalike condition, because his blood sugar level was out of control, increasing the pressure on his brain. For six months, the young man was in a vegetative condition, the level of consciousness right before a coma. He almost never moved, and did not react to sound nor light, and as there were no signs of improvement, doctors estimated that the condition would become permanent. But today, Asbjørn can walk about his flat on his own, and he eats and drinks and loves to have his family come visit.…

YOU WILL NEED: 100 g of potato flour 100 ml of water A bowl A spoon for stirring An old speaker Glad wrap GUIDE: 1 Mix potato flour with half of the water. Stir, and slowly add the rest of the water, until everything is fully mixed. You could add a little food colour. 2 You can test whether the fluid has the right consistency by pressing your finger into the mixture. If the mixture offers resistance, and it is difficult to insert your finger, it is just right. 3 Explore the characteristics of the mixture: Make a fist and hit it hard into the bowl. Pick up the mass and shape it into a ball. Then relax your hand and see if the ball keeps its shape. 4 If…