many different walks of life. are. and oddly trying to come true from the heart. of. the russian internet journey to get charged to maintain g.w. . how. global energy consumption rises every year many people's biological rhythms are no longer in sync with day and night but more with artificial light love does that mean for us energy demands also to keep the natural resources renewable energies could help more if they were more efficient one idea is to use lenses to focus on light more precisely on the solar cells in the panel. welcome to

tomorrow today the science show on d w. last. how do solar cells actually was so hisself are mainly composed of silicon. silicon atoms have full electrons in the outer shell and are stable but then the silicone is split into 2 layers. bosphorus is mixed into one layer it has 5 electrons in its outer shell one too many which can orbit free. 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 layer to the other one layer loses in. trans and becomes positive the other gains electrons and becomes negative

create 2 poles eventually all the gaps on the surface of the law is occupied the whole and the electrons are now too far apart to migrate that is where the sun comes in when some light hits the surface layer images splits on one electron making a hole under so close election. the electron is attracted to the positive and the hole goes another electron from lower down to replace the one longs which in turn is split off and so on. the electrons which have the right at the positive pole return via one head to the negative call that's 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 there's still a lot of work to be done. research is

forging ahead. florian gallies has come up with a new method of extracting even more power from sunlight. but. what we've 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 they're expensive and above his expensive solar super cells yellowish months 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 doesn't it won't produce any energy at all. and dropped a manicure. in gallic celebratory. we get an idea 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. and we use about $10000.00 sales per square meter and each has to have a high degree of tolerance. but now it's time for the engineers to put the lab behind them. right now we're 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 that's the really huge leap we're about to take that will fit in the us mafia. the european union is giving insulate almost 3000000 euros from its advent solar cell fund expensive science but worth it

. including installation ourselves or about 20 percent more expensive but they produce 50 percent more energy and. improved utilization of solar energy is one thing but it's 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 switzerland's materials testing and research institute show us how dangerous they can be if the lithium ion cells 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 and. 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. solar energy for foggy days or the night time in future we could be storing it in less volatile batteries than we have today. it's energy that could become abundantly available thanks to a new generation of panels to collect it.

ideally we wouldn't use any energy at all that's the idea behind the ancient dream of the cultural motion a machine that moves without any energy source but the laws of physics teach us that it's not possible i can't eat everything up and simply hope that the pull itself. if i use energy i have to replace it on the other hand. with that in. mind to. phoenix looks like. but it's actually an airplane or to be precise and unmanned aerial vehicle. the prototype the wings and tail will be added shortly we joined the team amid preparations for the 1st test might. 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 hands up 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 either 150 years and it's used underwater for remotely operated vehicles so there are various things called gliders are used underwater for surviving but nobody's made it work in a before because errors are sometimes less dense in 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 battery life meaning phoenix can also fly at night. this is phoenix in its fully assembled stage 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 that's where the weather is most benign. winds are much lower than they are on 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 doesn't

need to carry any fuel that means it can remain airborne for weeks or months at a time the mix is also relatively cheap to manufacture. it's propelled by what's 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 ability 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 it's lighter than air like

a balloon. the model has been through countless tests in wind tunnels. andrew ray is responsible for the aerodynamics and elements he's keen to improve further. 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 excluding waves down the $120.00 metre long hangar exactly as it was

designed to do. we were all pleasantly surprised that it worked as well as it did. we initially had hoped to. do one series of tests where was lighter than air and one had to navigate through so well to begin with that we were able to do multiple transitions between the 2 when it flew forward repeatedly during the flight trusting. work is now underway to build the next prototype it's 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 in a right of tiny luminous dots it could be beautiful in another context electric light does make modern life possible independent from the 24 hour a day night rhythm would have freedom but also what

a catastrophe it confuses the environment and we spend too much time in an artificial life and also nothing essential sunlight time for an experiment. these 3 people are exposed to different levels of light during their day. boss john works in an office which means spending long hours in artificial light. thomas is a goat herd and is mostly outdoors. then there is 19. a doctor who works as a surgeon in a hospital and she works at night when her body is telling her it's dark and time to go to bed. we equip our test subjects with a special device that measures the brightness and composition of the light they're

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 riata 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 go to church tends to be out in the open with natural like the lord even in gloomy weather he's 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. mall going.

site there's a very high a luminance in the morning and around noon up to $7000.00 lux dollars 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 that it's yet in accordance with the natural gauge or night rhythm effect the stock knocked over at most and splashed. john's case the g. takes place almost exclusively indoors just bite having large windows he always turns on the light but artificial light is usually very weak whereas goatherder traumas can reach 7000 lux bus john's level is just 220 bus general so spends most of his evenings in front of a t.v. or computer screen in addition to being low light they 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. cut in while working in the office we have 200 to 220 lux which is far short of daylight bite and found fun that. what we notice is that he still has a relatively high illuminance after work until he goes to bed. who are. hot this so and that he definitely has a negative effect on his sleep wake behavior. and he got the 5. now deemed as a doctor who likewise works with little light most of it artificial. and sometimes with practically none. and. i'm just a ripe for

a night shift saturday night which no one likes to see but i'm not properly rested even after. commission. 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 it's unnatural outside of course it's dark. if she's lucky and it's a quiet night nadine will be able to take a break and catch up on her sleep. but it's only a matter of time until she's called to the next patient which means getting up again pronto. the rude enough to. even though my night shift is over and my colleague is now taking over for the daytime shift and which display i'm cafe but you can't really look forward to going home when you know you'll be back again this evening tonight with the food and this

is what her light exposure chart 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 there's no daylight rhythm at all as far as light exposure is concerned the least exposed it's on there and she's 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. line shows the light on a typical morning for office worker boss john 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 come no office worker and doctor get more like. we'll have the solution for you in a moment but 1st of all we asked how much you have to rely on artificial light and if you have strategies for avoiding too much of it. brown says they don't have too much artificial light in nigeria so they don't really depend on it. rising from columbia most head tells us it really makes us sad that light pollution means she can't see the greatest show on earth the milky way it's like a cascade of diamond spots in the sky. and factor tells us that pakistan's will areas have barely any artificial light at night the people there are healthier than city people they're also very strong

emotionally they stay calm worry less and mostly smile 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 recently. many professions are rescheduling work to have and i have a nice song only work at night but how can you stay healthy despite that. that daylight experiment. tomas spends most of his days outdoors so he gets plenty of natural light in the tennis to avoid screens their blue spectrum output he's just fine but bass john's 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 he'll be more capable and alert in the morning with the highest for bastiaan that means 1st thing in the morning it's out into the fresh air and natural g. 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 he's 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 displayed 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 component sharply

damage come on all it lets you use your smartphone it without feeling guilty about disrupting your sleep it's the stuff they start out. but others do this is the time the system will stop with the daylight lamp and walking in broad daylight i've got a feeling that i get tired very much earlier at night and want to go to sleep. on stuff given it gets on my nerves a bit because i like to stay up late. you know. what i don't feel like i'm struggling to get through the day like i used to before this whole experiment publishing issue d. just feet of the ship instead and quite often much more alert. hospital dr 19 really gets much daylight and her night shifts go counter to her biological clock adrenalin is what keeps her remarkably awake at work. to feel

she's doing a lot right she's 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 she'll 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 lies is just that much we know it also helps us to produce this mental essential for both development and also said to boost the immune system but getting

the right amount of sunlight is important too much u.v. light is unhealthy the world long ago adapted to the sun's 24 hour rhythm it's regulated human life for thousands of years but how did it come about in the us from zambia wanted to know. how was the sun created. it's been burning away for over 4 and a half 1000000000 years and it's not even high. through its projected life span. 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. it's a magical process reproduced here on a computer. this cloud of dust contains regions of denser gas like pearls on the necklace. the astral embryos that emerge there continue growing until they have sufficient mass to ignite the sun spire. if outlet is red why of it but even. if you have a science question that you've always wanted on state we're happy to help out a little less as a video text ovoid smell if we answer it on the show we'll save you a little surprise as

a thank you can i just ask. you to like to see more science stories then visit albert size or follow us on twitter on facebook. that's all from tomorrow today for this week next time we'll be looking at the power of thought we'll be able to operate machines just by thinking the 1st models to be tested more on that next week.

money's life was saved by the so-called enemy he's a palestinian from the gaza strip hospital in israel provided crucial medical treatment. going home is not a realistic option since he's been living for years in the hospital with his

grandfather heard. across the water. 15 minutes long d.w. . nor did it what do they dream of at night. as cleaners they see the face of horror. job since room for the social media industry. in manila there are thousands of so-called content monitors day for today they scrub terrifying images from online platforms to her recent job for starvation wage. the strain is enormous. and we. need to stop there something warm up to.

the cleaners social media's shadow industry starts tonight on g.w. . been told it is for me. is for. beethoven is for him beethoven is her. and beethoven is for. beethoven is for everyone. beethoven 2022 and 50th anniversary here on d w. i'm doing crazy thing in all the time. how to handle on new allies in times of the corona pandemic d.w. reporter. just like everyone else and she's looking for answers and thankfully with the help of cleaning expects to join the party bosses are. just ok thank you is not

life as we know it we're in this together our new web series. this is dave news live from berlin an album night of chaos across america has been widespread looting as anger of the death of george floyd in police custody again boils.