To tomorrow today the science show on d w. Last. Stop how do solar cells actually but so hisself are mainly composed of silicon. Silicon atoms have full electrons in the outer shell and are stable but then the silicon misplaced into 2 layers. Bosphorus is mixed into one like it has 5 electrons in its outer shell one too many which can orbit freeney. The 2nd layer is mixed with boron which has only 3 out electrons one to feel. That means the layer has gaps which attract the excess phosphorus electrons this creates a flow of negatively charged electrons from one line to the other one layer loose. As electrons and becomes positive the other gains electrons and becomes negative create 2 poles eventually all the gaps on the surface of the layers are occupied the whole and the electrons are now too far apart to migrate with the sun comes in when some light hits the surface layer energy splits off one electron making a hold on to so close electron. The electron is attracted to the positive and the home goes another electron from lower down to replace the one longs which in turn is split off and so on. The electrons which of arrived at the positive post return via wire to the negative call thats an electric car. And it flows as long as the sun shines. If solar energy is to enable commercial aviation and satisfy our electricity needs in the future then theres still a lot of work to be done. Research is forging ahead. Florian galushas come up with a new method of extracting even more power from sunlight. But. What weve done instead of using normal silicon solar cells which have a maximum Laboratory Efficiency of 26 to 27 percent is to use somewhat more exotic cells their maximum Lab Efficiency is over 47 percent but theyre expensive and above his expensive solar super cells a panel of lenses each of which focuses sunlight on an individual cell throughout the day that boosts efficiency to 29 percent in real life conditions. The main challenge is making sure the light actually hits the cell if it doesnt it wont produce any energy at all. In gaelic slow burn. Of how it works he uses a model to show how the lenses function each lens in the top panel focuses the sunlight on an exactly defined radius covering a super cell. Because those cells are tiny barely one millimeter across. We use about 10000. 00 cells per square metre and each has to have a high degree of tolerance. But now its time for the engineers to put the lab behind them. Right now were still almost sticking everything together by hand but now the important step is going from the lab to mass production how can i produce a module every couple of minutes using machinery thats the really huge leap were about to take that will fit in the of mafia. The European Union is giving insulate almost 3000000 euros from its head friends solar cell fund expensive science but worth it. To including insulation our cells are about 20 percent more expensive but they produce 50 percent more energy. Improved utilization of solar energy is one thing but its also highly dependent on the weather it only makes sense when electricity Storage Facilities have been improved. Lithium ion batteries are the standard today but scientists at switzerlands Materials Testing and Research Institute show us how dangerous they can be if the lithium ion cells insulation is compromised and the terminals come into contact with metallic objects such as coins the result can be disastrous. Thanks. Our approach to stabilizing the electrolytes involves a highly concentrated salt solution. The swiss researchers have developed a highly soluble salt that only needs a few drops of water here seen in fast motion to function as a more conductive but much safer electrolyte in lithium ion batteries. That kind of storage battery would be enormously useful for storing solar energy in people cellars or in other very large batteries. To bridge the nighttime gap as well as bad weather. Batteries are the ideal solution for delaying Energy Consumption for a few minutes or even days. Solar energy for foggy days or the night time in future we could be storing it in less volatile batteries and we have today. Its energy that could become abundantly available thanks to a new generation of panels to collect it. We wouldnt use any energy at all thats the idea behind the ancient dream of the petrol motion a machine that moves without any Energy Source but the laws of physics teach us that its not possible i cant eat everything up and simply hope the biscuit to pull itself. If i use i have to replace it on the other hand. Without an engine that might just. Phoenix looks like. But its actually an airplane or to be precise and unmanned aerial vehicle. Its. The prototype the wings and tail will be added shortly we joined the team amid preparations for the 1st test flight. The researchers have chosen a huge building for their 1st attempt to get phoenix into the air a tense moment for its inventors. Scientists from various universities and companies in britain spent 3 years working on phoenix. Aerodynamics professor andrew rank and the team. Says. The goal was to build an aircraft that could propel itself without the need for an engine. Has been around for a long time ive 150 years and its used underwater for remotely operated vehicles so there are various things who died is used underwater for surviving but nobodys made it work the night before because there is a sound sometimes less dense and water that the physical process is more complicated phoenix is filled with helium the material for the outer hull had to be developed specially it needed to be lightweight but dense enough to prevent the tiny helium molecules from seeping through. The wings are made of lightweight carbon fiber both the wings and tail carry solar panels to provide the plane with power some is stored in batteries meaning phoenix can also fly at night. This is phoenix in its fully assembled steam engine the aircraft will likely be used as an atmospheric satellite or pseudo satellite either for telecommunications or for things like land surveillance after natural disasters to see where help is most needed one of the possibilities is as a suit our satellites are being able to do surveillance and monitoring and for that it would fly at 20000 meters and 20000 meters because thats where the weather is most benign. A much lower than the surface phoenix is 15 meters long and weighs just 120. 00 kilos without the helium. That means it requires very little power. Its huge advantage is that because it has no engine it doesnt need to carry any fuel that means it can remain airborne for weeks or months at a time. Phoenix is also relatively cheap to manufacture. Its propelled by whats known as variable buoyancy propulsion this is how it works. And is lighter than air and therefore pulls the aircraft up towards the underside is equipped with 2 compressors which draw in air from outside and compress it filling a bag inside the aircraft. That makes the plane heavier causing it to sink again. The air is then pumped out making the aircraft lighter and causing it to rise again this stability to believe as it were moving up and down combines with the lift generated on its wings to move it forward. Half the time phoenix is heavier than air like an airplane. The other half its lighter than air like a balloon. The model has been through countless tests in wind tunnels. Andrew ray is responsible for the aerodynamics and element hes keen to improve further tests. Using lasers and smoke his team is able to show how the air flows around the model. They needed to establish the most efficient design to allow the aircraft to maximize the use of its kinetic energy. Here. After 3 years of development the prototype was ready for its 1st test flight. And it was a success phoenix flew in waves down the 120 metre long hangar exactly as it was designed to do. We were all presently surprised that it worked as well as it did. We initially had hoped to. Do one series of tests where was like the narran one had to navigate for solo to begin with that we were able to do multiple transitions between the 2 when it flew forward repeatedly during the flights or structural work is now underway to build the next prototype its said to be 4 times a small miss phoenix and capable of flying at the target altitude of 20000 meters. The earth by night covered by an iraqi of tiny luminous dots it could be beautiful in another context electric light does make modern life possible independent from the 24 hour day night rhythm of freedom but also what a catastrophe it confuses the environment and we spend too much time in us official ice and also enough in essential sunlight time for an experiment. These 3 people are exposed to Different Levels of light during their day. Bastiaan works in an office which means spending long hours in artificial light. Thomas is a go to herd and is mostly outdoors. Then there is 19. From a doctor who works as a surgeon in a hospital and she works at night when your body is telling her its dark and time to go to bed. We equip our test subjects with a special device that measures the brightness and composition of the like theyre exposed to. And then we track them around the clock for a week. We want to know how much and what type of light our test subjects are exposed to and when. Sleep researcher alfred and light expert because it analyze the results. What will they show how much like to our subjects received at what time of day. Tomas the goat it tends to be out in the open with natural like a lord even in gloomy weather hes subject to several 1000 locks per day. After sundown he manages without a television or mobile phone which both emit a lot of blue light and are disruptive. This shows the amount of Natural Light thomas is exposed to over the course of several days in the. Malden. Site theres a very high a luminance in the morning and around noon up to 7000 lux and looks on and in the afternoon it drops significantly. Around 100 lux or lower looks on need. And at night the light exposure is reduced to an absolute minimum of absolute minimum i dont see it is in accordance with the natural day genetic rhythm that the stock knocked over most and placed. In bunce johns case the g. Takes place almost exclusively indoors despite having large windows he always turns on the lights but artificial light is usually very weak whereas goatherder traumas can reach 7000 lux bastions level is just 220. 00 plus channel so spends most of his evenings in front of a t. V. Or computer screen in addition to being low light the emit primarily blue light this lowers the wake sleep regulating hormone melatonin and reverses his inner rhythm essentially turning back his biological clock and the result for us john is this modest hour by hour exposure to light on a typical working day then had to cut in but while working in the office we have 200. 00 to 220. 00 lux which is far short of daylight light and found that august least what we notice is that he still has a relatively high illuminance after work until he goes to bed. Who are. Hot this summer and that definitely has a negative effect on his sleep wake behavior and. Its got the 5. Now deem is a doctor who likewise works with little light most of it artificial. And sometimes with practically none. And. Im just a ripe for a night shift saturday night which no one likes to see but im not properly rested. But she needs to be wide awake not least when stitching up a wound at 1 am. The surgery room light is particularly strong which helps right now but for her biological clock its unnatural outside of course its dark. If shes lucky and its a quiet night nadine will be able to take a break and catch up on her sleep. But its only a matter of time until shes called to the next patient which means getting up again pronto. The rude enough to 50 even so my night shift is over and my colleague is now taking over for the daytime shift and which despite im could feel that you cant really look forward to going home when you know youll be back again this evening when it was. And this is what her light exposure tried looks like. And then. Come on for the 1st 3 days you can see a relatively good day night rythm after that her night shifts begin. And then theres no dana rhythm at all as far as light exposure is concerned the least exposed its still in there and shes more or less exposed to continuous lighting. And that constant light is anything but natural. Her biological clock has no means of orientation. In order to reset her clock back to normal she needs jail right in the morning between 8 and noon a time of day where our 3 subjects differ substantially in exposure. The blue line shows the light on a typical morning for Office Worker. Read is that of dr 19 and green go to her tomas whose exposure is 10 times higher in those crucial morning hours. So how can the Office Worker and dr get more like. Well have the solution for you in a moment but 1st of all we are asked how much you have to rely on artificial light and if you have strategies for avoiding too much of its. Brown says they dont have too much artificial light or nigeria so they dont really depend on it. And rising from colombia most have tells us it really makes us sad that Light Pollution means she cant see the greatest show on earth the milky way its like a cascade of diamonds sparkling in the sky. And fucker tells us that pakistans rule areas have barely any artificial light at night the people there are healthier than city people theyre also very strong emotionally they stay calm larrie less and mostly small thanks for writing in. Even if in some regions night time still looks like night time the world as a whole has been getting brighter which simply. Many professions are rescheduling glad to have and i have a nice sun only work at night but how can you stay healthy despite that. Fact tell a daylight experiments. Thomas spends most of his days outdoors so he gets plenty of Natural Light in the evenings he tends to avoid screens with their high blue spectrum output hes just fine but Bastions Office job means he has a serious light deficit problem and not just because his office is too dark. An Office Worker circadian rhythms are completely disrupted and we should try to adjust his biological clock. So hell be more capable and alert in the morning and the highest for bastiaan that means 1st thing in the morning its out into the fresh air and natural jay light not exactly a grueling task skipping one stop on the subway into work is all it takes. We also install a standard daylight lamp on his desk for him to use during the morning that way hes getting 2000 lux even in the office. And in the evening a book is always better than a screen. Measurements show just how even a smartphone can influence our sleep patterns normal display light is dominated by the blue spectrum that suppresses melatonin the hormone that steers our weak sleep rhythm however many smartphones now feature a filter called night shift it cuts down the blue spectrum components sharply. Lets you use your smartphone without feeling guilty about disrupting your sleep the stuff they start out. But others do this is the time to see something with the daylight lamp and walking in broad daylight ive got the feeling that i get tired very much earlier at night and want to go to sleep. When traffic gives me it gets on my nerves a bit because i like to stay up late and. What i dont feel like im struggling to get through the day like i used to before this whole experiment how big an issue would be discreet as you can stay and quite often much more alert the. Hospital doctor 19 really gets much daylight and her counter to her biological clock adrenaline is what keeps her remarkably awake at work the. Fever shes doing a lot right shes limited by her night shifts of course what is important is that she at least grabs whatever sleep she can when on shift. The sleep experts offer her another suggestion after a night shift dr specially colored glasses which filter out that studies are melatonin level and sleep easier when she gets home the experiments outcome is that the most important thing is to get a lot of natural daylight preferably in the morning that way the biological clock settles into its natural rhythm and also to try to go without screens in the evening and if night shifts are a must then only a few of them at a time grouped together a well maintained biological clock never needs reminding. So some lines is best that much we know it also helps us to produce this mental. Development and also said the immune system but getting the right amount of sunlight is important too much. Isis unhealthy the wolves long ago the data to the sons 24 allover them its regulated human life for thousands of years but how did it come about amos from zambia wanted to know. How was the son created. Its been burning away for over 4 and a half 1000000000 years and its not even halfway through its projected life style. One in which Human History is just the blink of an eye. But while we may be just a transitory moment in cosmic terms we are at least able to study the life cycle of the sun. Our galaxy is home to billions of other stars like it. Space telescopes have given astronomers a closer look at how stars evolve. Our own son was born from a cloud of gas and dust over the course of millions of years. Its a magical process reproduced here on a computer. This cloud of dust contains regions of denser gas like pearls on a necklace. The astral embryos that emerge there continue growing until they have sufficient mass to ignite the sun spire. If outlet is right why up it didnt even take. To you have a science question that youve always wanted on state were happy to help out send it to us as a video text ovoid smell if we answer it on the show well send you a little surprise as a thank you can i just ask. You to like to see one. Sign stories then visit our web sites or follow us on twitter and facebook. Thats all from tamara today for this week the next time google looking at the power of thought well be able to operate machines just by thinking the 1st models are already being tested more on that next week to see them. Coming. Up from a. Little. Specializes in fantasy venture. Readers the world over practically devour her. Meat and the artists me curled up with the creator of fantastical world to an exclusive interview. From game do you do an. Arch 21. Coming up on d w. Take. A chance walk. Into shimmering fabric fashions into elegant clothes like a young designer. Upcycling trash and. What else would he find on the dump. Your. 30 minutes on d w. One the hour rises cities will sink into the sea. Entire stretches of land will be abandoned. And the water. Rises. Stopped its happening faster than anticipated. Massive us are supposed to prevent flooding but they only delay the inevitable. How will we live