well you. know the ideas of these holds sway to bring you more conservation. how do we make cities greener how can we protect have a chance or we can make a difference to the idea of a mental series of global powers of g.w. i don't mind. 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 what does that mean for us our energy demands are also depleting 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. stuff

how do solar cells actually was surface else are mainly composed of silicone. silicon asms have full electrons in their outer shell and are stable but then the silicone is split into 2 layers. bosphorus is mixed into one like it has 5 electrons in its outer shell one too many which can orbit for. 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 electrons and becomes positive the other gains electrons and becomes negative creating 2 poles eventually all the gaps on the surface of. is occupied the holes

and the electrons are now to florida plant to migrate them with the sun comes in when some light hits the surface layer splits on one electron making a hold on to supply selection. the electron is attracted to the positive and the hole goes another electron from lower down to replace the one lost which in turn is split off inside. the electrons which have the right at the positive pole returned by one year 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 galusha's 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 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 and it won't produce any energy at all. and drop them in it you know. in gaelic celebratory we get my 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 cells 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 with you 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 of 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 insulation is compromised and the terminals come into contact with metallic objects such as coins the result can be disastrous. thank. you. 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. in the batteries are the ideal solution for delaying energy consumption for a few minutes a day in. solar energy for foggy days or the night time in future we could be storing it in less volatile batteries and we have today. it's energy that could become abundantly available thanks to a new generation of panels to collect it. we wouldn't use any energy at all that's the idea behind the ancient dream the cultural motion 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 the biscuit to pull itself if i use energy i have to replace it on the other hand and with that in. that my to. phoenix looks like. but it's actually an airplane or to be precise and unmanned aerial vehicle. it's to. 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 ray heads 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 my 150 years and it 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 84 because there is a sound sometimes less dense and mortar that took 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 and it's fully assembled station 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 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 reinsert 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 phoenix flew in waves down the 120 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 like the narran one had to know but it flew so well to begin with that we were able to do multiple transitions between the 2 when it flew forward repeatedly during the flight testing. work is now underway to build the next prototype it's set to be 4 times a small miss phoenix and capable of flying at the target down to tune 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 would have freedom but also what a catastrophe it confuses the environment and least spend too much time in us official lies 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 herder and is mostly outdoors. then there is not. 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 like 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 receive at what time of day. tomas the gold it tends to be out in the open with natural light galore even in gloomy weather he 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 on the meter 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 they don't see it in accordance with their natural gauge a night rhythm effect the stock knocked over at most and placed. in bunce jones case the day takes place almost exclusively indoors despite having large windows he always turns on the light but artificial light is usually very weak whereas goatherder traumas can reach 7000 lux bastions level is just $220.00 plus gen 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 energy 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 they are cutting but while working in the office we have $200.00 to $220.00 blocks which is far short of daylight vite and found fun that. what we notice is that he still has a relatively high illuminance after working until he goes to bed. who are. hot this so and that he definitely has a negative effect on his sleep wake behavior and. and you got the 5. now deem is a doctor who likewise works with a little light most of it artificial. and sometimes with practically none. and now i'm just a ripe for a night shift saturday night which no one likes will see but i'm not properly rested even after. we finish. 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 side 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 wounded nothing 50 even so my night shift is over and my colleague is now taking over for the daytime shift and which just by i'm could feel that you can't really look forward to going home when you know you'll be back again this evening when it was the flu and this is what her light exposure chart looks like. and then. going

on for the 1st 3 days you can see a relatively good day night rhythm after that her night shifts begin. and then there's no daylight rhythm at all as far as light exposure is concerned at least expose its own when 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 daylight in the morning between 8 and noon a time of day or 3 subjects differ substantially in exposure. the blue 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

can the office worker and doctor get more like. we'll have the solution for you in a moment but 1st of all be honest how much you have to resign an artificial light and if you have strategies for avoiding too much of it's. brown says they don't have too much artificial light and i tear it so they don't really depend on it. rising from columbia mo said tells us it really makes us sad that light pollution means she can see the greatest show on earth the milky way it's like a cascade of diamonds spotting in the sky. and doctor tells us that pakistan's rule 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 laurie 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 an i have a nice song only work at night but how can you stay healthy just like that. that daylight experiment. spends most of his days outdoors so he gets plenty of natural light in the evenings he tends to avoid screens there i believe spectrum output is just fine but past john's office job means he has a serious light deficit problem and not just because his office is too dark or wonder stating 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 fit into the hottest for bastiaan that means for. 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. measurement 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. damn it come on all it lets you use your smartphone without feeling guilty about

disrupting your sleep. the stuff they start out. but others do the only time you see something 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. it gets on my nerves a bit because i like to stay up late. what i don't feel like i'm struggling to get through the day like i used to before this whole experiment how did he just. did i'm quite often so much more alert the. hospital doctor 19 really gets much daylight and her night shifts go counter to her biological clock adrenaline is what keeps her remarkably awake at work the. 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 should try 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 rewinding. so some lysis best that much we know it also helps us to produce essential for development and also said to boost the immune system getting the right amount of sunlight as opposed to much. isis unhealthy the world long ago adapted to the sums 24 hours

over them it's regulated human life for thousands of years but how did it come the balance amos from zambia wanted to know. how was the son created. it's been burning away for over 4 and a half 1000000000 years and it's not even halfway through its projected lifespan. 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. all 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 a necklace. the astral embryos that emerge there continue growing until they have sufficient must to ignite the sun's fire. if outlet is right why up in latin. do you have a science question that you've always wanted on state we're happy to help out send it to us as a video text ovoid smell if we answer it on the show let's send you a little surprise as a thank you cannot just honest. to like to see even one. sign stories then visit our website or follow us on twitter on facebook. and.

that's all from tomorrow today for this week the next time google looking at the color of thought will be able to operate machines just by thinking the 1st models are already believe tested more on that next week to see them. the be. going to.

come. it's a deadly sin. and the basic human trait. is drives us the branch threatens to destroy a. group. in part to taming greed is now a matter of survival much is it really something we can do to greet the fatal desire. in 15 minutes on d w

o board all. of that i don't need to keep a debate about a notable role for over a mention on the force i believe the whole toaster semitic number was the bottom of the ballet that the last dragon was worth. the norm for me is nothing. like. oh. my god says love. food for the russian soul. it runs deep. so many different blocks of life. some are bumping into our. goals come straight from the heart. the russians and turning from birth to death starts june 18th on g.w.

. nor even what do they dream of at night. as cleaners they see the face of horror. their job censoring for the social media industry. in the uk there are thousands of so-called content monitors day for day they scream terrifying images from online platform or some horrific job for starvation wage the stream is enormous. the cleaners are sworn to secrecy they are not allowed to talk about their work. and no one asks how they are doing. it. i need to stop there something was up in. the cleaners social media shadow industry starts joining us on g.w. .

the book. this is d.w. news live from berkeley another night of pails in the u.s. says protesters demanding justice for george floyd was killed in police custody the city of minneapolis later this week the unrest following his death has given rise to a 4th night of demonstrations that have rocked cities across the country. also coming up marching out to freedom the afghan government releases taliban prisoners a spot of a peace deal of the future remains uncertain as fighting rumbles on.