Secrets of the Sun - Universe Space Documentary

Our nearest star. In the fall of 2003, it unleashed an eruption of energy equal to 200 billion hydrogen bombs. Blasting a tidal wave of superheated charged particles at speeds of up to 6 million miles an hour, it was one of the largest solar storms ever recorded. And it was aimed at Earth. They were some of the fastest, hottest, and strongest storms ever measured. Assaulting the Earth, the sun's energy forced space station astronauts to take cover in their most sheltered compartments. Lights went out, communication streams were cut, airliners scrambled for safety. This really was a hurricane of space storms. Though no major damage was done, these storms were a stark reminder that we live at the constant mercy of the sun. It controls all aspects of our lives. Our climate, our food, our bodies. We actually live inside the sun's atmosphere. We, along with all the other planets, are greatly influenced. But is its influence changing? It's actually growing more powerful. Might we lose its protection from deadly cosmic rays? At its boundary, where it's protecting us from the intergalactic winds, that boundary is actually shrinking a bit. Will our technology-dependent society be able to handle another solar superstorm? Sometimes these effects can be so severe that they're catastrophic. And when will the next superstorm strike? 3, 2, 1, go for drop. 2008. NASA launches IBEX, the Interstellar Boundary Explorer. Part of its mission is to study the effects the sun has on the furthest reaches of our solar system. IBEX joins the long list of human attempts to explain our star's impact on our solar system, our planet, and our lives. The sun. The sun provides all of our light and heat. If it weren't for the sun, we wouldn't be alive. We people are very interested in what goes around us. We like to understand our neighborhood. The sun in the universe is our street, our neighborhood. The sun. We are actually affected by its moods. In fact, it's like the parent in all the planets are the children that are affected by its moods. We need to know how it's going to evolve and how the changes that are always happening in the sun affect us here on Earth. The sun. If we want to understand the universe and the stars that make up the universe, then it's important to study the one that's closest to us. We've learned more about the sun in the past 40 or 50 years than in all of recorded history. This golden age of exploration was kicked off by a unique mission that gave us close-up images of our sun from above our atmosphere. In 1973, Skylab became the first manned space station. It sent back images of the sun clearer than anything taken from Earth. The Skylab mission was one of the very first laboratories that was dedicated just for the research and study of the sun. In some ways, it's kind of the grandfather of the current missions today. Right now, a fleet of about 20 space probes scan and study the sun in ways we never imagined even 30 years ago. By studying the sun from the vantage of space, we can see it in a whole new light. Using different light wavelengths, including X-ray and extreme ultraviolet, we can peel back its layers and begin to understand how and why the sun acts the way it does. Different wavelengths mean different temperatures, and different structures are more visible in different wavelengths than in others. Our robotic space probes never stop watching the sun. With their help, scientists are working out the big questions about our star, and we already know a lot. The sun is one of over 200 billion stars in our Milky Way galaxy, but it is our closest at 93 million miles away from Earth, almost the same distance as 4,000 trips around the globe. And despite that distance, its light only takes 8 minutes to reach Earth. It is only 4.5 billion years into its nearly 10 to 11 billion year lifespan. And though technically a medium-sized star called a dwarf, it is enormous, 900,000 miles across, and if hollowed out, 1.3 million Earth-sized planets could fit inside. The sun accounts for 99.8% of the mass in the solar system, and it weighs 300,000 times more than the Earth. It is made up almost entirely of a superheated form of electrified and magnetized gas called plasma. The sun packs enough gravitational pull to keep the planets from spinning off into space, and as Copernicus first suggested, it rules the center of our solar system with a gravitational iron fist. Copernicus' model, in which he placed the sun in the middle of the solar system with all the planets going around it, instead of everything going around the Earth, was a giant paradigm shift. It meant that the sun is the most important thing in the solar system. It meant that we really should understand the sun. Our sun, like all other stars in the universe, is made from the dust of stars that lived and died over billions of years, going all the way back to the Big Bang. So our sun and our solar system is really the debris from many generations of stars. The sun we see every day is the solar system's source of power. Deep in the center of our star, its core is superheated to 27 million degrees Fahrenheit and is the engine that drives it all. Inside the sun's core, the process of fusion is occurring, and that fusion process is giving off light and particles. Every second the sun shines, it releases the same amount of energy as one million H-bombs. The sun's light is made of particles called photons, born in the core, then propelled by convection currents through the radiative and convective zones of the sun. Eventually, they reach the volatile outer layers of our nearest star. The sun's outer parts consist of three regions. There's the photosphere, or surface of the sun, and it's not really a hard surface like that of the Earth. The sun is gaseous throughout, and the temperature of the photosphere is around 10,000 degrees Fahrenheit. Above the thin layer of the photosphere is another thin layer called the chromosphere, and the chromosphere is slightly hotter than the photosphere, which is counterintuitive because you would think that as you go away from the source of all the energy and heat, the core, that temperature would drop. But in fact, the temperature rises from the photosphere to the chromosphere, and it gets even hotter as you rise to the third layer of the atmosphere called the corona. And then beyond the chromosphere is a large, tenuous, extended region, the corona, which is millions of degrees. The sun produces a continuous outward flow of energy called the solar wind. Constantly blowing, it carries energy out into the solar system, extending our sun's reach 9.3 trillion miles, well beyond Pluto. The space in between the planets and the space in the entire solar system is not an empty void, but it's full of these particles, and it's full of these rays of light. While the solar wind blows away from the sun, its gravity holds and pulls everything in. Take comets. All comets orbit the sun and can get pulled directly into the line of fire. Recently, scientists witnessed one of the sun's most dramatic outbursts, a coronal mass ejection ripping the tail off a comet. When it hit the comet, the tail was cut off like it's a knife, and the tail drifted away, and then it took a little more time for the comet to generate more gas and plasma and dust and create a tail. It tells us about how the solar wind moves in the solar system and how it can affect things. The sun affects everything it touches, even us. To learn just how much, scientists sometimes rely on a remarkable cosmic coincidence. The lethal output of the sun has made studying it almost as difficult as understanding it. But scientists can get a good look at our nearest star thanks to a cosmic coincidence. A total eclipse of the sun. A total solar eclipse occurs when, from our perspective, the moon is exactly aligned with the sun and blocks its photosphere. It's a glorious sight. The solar eclipse is the most wonderful thing to see. It grows really dark by factors of thousands within seconds. And as it does become so dark, you can look up in the sky, you see the dark shadow coming from one direction, sweeping at you. It's really coming at thousands of miles an hour. So it's very impressive to see. Humankind has marveled at the mysteries of the eclipse for millennia. Scientists have used it as an opportunity to see the sun's outer atmosphere, the enigmatic corona. One of the hottest regions of the sun, energy from the corona radiates out to the edge of the solar system. The entire solar system actually sits in this outer corona of the sun. So this atmosphere of the sun is bathing all the planets. The engineers who built the Solar and Heliospheric Observatory, or SOHO, installed an artificial eclipse into the space probe. Called a coronagraph, it does the same thing as a natural eclipse, blocking out the blinding rays of the sun, so scientists can try and answer an old question. How does the solar corona get so hot? After all, the everyday surface of the sun, the photosphere, is only around 10,000 or a little more Fahrenheit. And the corona, on the other hand, is millions of degrees hot. If you go away from a stove, you know it gets cooler, but if you go away from the everyday surface of the sun, it gets hotter. And how is that? It all starts at the sun's core, where every second, nearly 700 million tons of the universe's most common element, hydrogen, are converted into helium through nuclear fusion, giving off the energy that becomes photons, otherwise known as light. The sun's core is really hot, several tens of millions of degrees, and there the temperatures are so high that protons, hydrogen nuclei, can come together, grab each other, fuse eventually into helium. And in this way, release energy. What happens with these photons, they go through this process, what we call a random walk, where they have to go through the layer of the sun, they get absorbed and then reabsorbed into lots of different photons at lower energy level. So this process of being absorbed and reabsorbed millions of times can take 150,000 years. Once out of the sun's interior, photons are only eight minutes away from Earth, but they're leaving behind a world in constant motion. The solar surface boils. Energy rises constantly from below. Coils of plasma and energy, called coronal loops, spring across the sun, while dark regions, known as sunspots, stretch thousands of miles. And at only 7,000 degrees Fahrenheit, these sunspots are the coolest part of the sun, emitting less light than the surrounding area. If you were to pluck a sunspot away from the sun and place it in the sky, it would actually be as bright as the full moon. Sunspots appear on the surface and are easy to see. Their genesis, however, is tied to the sun's deep interior and complex rotation. The sun doesn't rotate like a solid body. Instead, it rotates more quickly near the equator than near the poles, which leads to sunspots. The equator completes one rotation in 25 days. Mid-latitudes complete one rotation in about 30 days. And near the poles, one rotation is completed in about 35 days. Called differential rotation, this process makes the sun's interior churn at different speeds, creating intense magnetism in the form of millions of magnetic field lines, which get mixed up as the sun's interior twists up like a rubber band. This builds up pressure, which makes them buoyant. So they flow to the surface, and where they pop through the surface, they create sunspots. Once on the surface, the now twisted and balled-up magnetic field lines block the convection of super-hot plasma from rising, making sunspots appear dark. And when those sunspots start to twist around, you can imagine that you have one sunspot here and one sunspot here, and there's a magnetic field that connects the two. And that magnetic field gets twisted, and eventually, the same sort of thing that happens with a rubber band, it pops. When the magnetic field pops, it releases energy. And in the case of the sun and solar flares, it releases huge, huge amounts of energy. The magnetic field lines created by the twisting and churning of sunspots, though invisible, can be seen in the dramatic formations on the surface of the sun, in the form of flares and prominences. It is here that the sun's influence starts, as the breaking of these magnetic field lines drives massive amounts of energy from our nearest star out into the solar system. And it is these magnetic field lines that are behind most theories on why the corona is so much hotter than the surface. It's pretty clear that it has something to do with the magnetic field that heats the corona. But presumably, there are waves along the magnetic field that bring energy from underneath the surface of the sun into the corona. The solar probe Hinode, which means sunrise in Japanese, was launched in 2006. Its mission, to study the interaction between magnetic field lines and the corona. Recently, it captured images of one of the waves thought responsible for heating this enigmatic region, Alfvén waves. Alfvén waves are waves that occur in a plasma, in a bunch of ionized gas, threaded by a magnetic field. And indeed, it's thought that these Alfvén waves might be bringing turbulent energy from inside the sun out to the corona, where that energy heats the corona. Energetic Alfvén waves form inside the sun and travel up through the surface, making the looping magnetic field lines sway and vibrate. And so through this vibration or this oscillation, they're having friction with the magnetized plasma surrounding it in the corona. And through this friction, the heating occurs. It's this heat, delivered to the corona, that radiates out into space, filling our solar system with the sun's energy. But this energy is not constant. Our sun is an ephemeral body, never the same from one day or one year to the next. Like Earth changes with seasons, so does the sun. And when the solar seasons change, anything can happen. Day in and day out, the sun we see appears the same. But like Earth, the sun has seasons, solar minimum and solar maximum, two distinct personalities that can affect our technology and possibly even our weather. The transition between solar minimums is called the solar cycle, an average 11-year period in which the sun's activity maxes out, then ebbs again. The primary measure of the solar activity cycle is the number of sunspots visible in the sun. During solar minimum, the period with the fewest sunspots, solar activity is limited. When sunspots break through the surface during solar max, the sun's power reaches out. When there are lots of sunspots, there are lots of flares and coronal mass ejections. Increases in solar activity enhance the connection between sun and Earth. Energy expelled from the sun can create disturbances in the near-Earth environment. The Earth is embedded in the solar atmosphere, and so what happens on the sun affects the Earth, and that's what we call space weather. Accurate space weather forecasting is the ultimate goal, but this can be hard. The sun is turbulent, especially during solar maximum, the peak of solar storm activity. During solar maximum, the magnetic field of the corona becomes very complicated, and you have magnetic field everywhere, all around, even near the poles. You can have coronal mass ejections and flares and solar storms occurring sometimes several times a day. Solar flares, violent eruptions of energy, usually near sunspots, burst into space. Like a bulk of lightning, quick and powerful, they can happen over a matter of minutes and can give off the same amount of energy as a billion megatons of dynamite. Solar flares are gigantic outbursts of energy from the sun, coming from a very small localized region of the sun's surface. So they're very concentrated ejections of energy that heat the surrounding gas to 10 million degrees. Solar flare is sort of like a snapping of the whip. It really releases a lot of energy very quickly, accelerating particles almost up to the speed of light. The particles from the very most energetic solar flares can reach us in something like 15 minutes. But the solar hurricane of space weather comes from coronal mass ejections. These massive blasts carry billions of tons of superheated gas and plasma into interstellar space. So a coronal mass ejection is where a huge amount of mass and energy is expelled away from the solar surface. So if you can imagine this huge amount of mass and energy traveling away from the sun at these large speeds, sometimes at over a million miles an hour. They throw these big bubbles of hot gas and magnetic field. It can move off the sun so quickly that it actually creates a shockwave. They're the biggest storms and they're the important ones for understanding space weather. Solar probes, like SOHO, have captured the sun, expelling massive amounts of energy into space. But scientists are most concerned when they see something called the halo effect, when the cloud of energy appears to surround the coronagraph. That means the sun has aimed its latest blast at us, like in the massive solar storms of 2003. The fastest coronal mass ejection ever studied in modern times came from these storms. Shortly after the initial blast from the sun, SOHO was bombarded by charged solar particles, protons and electrons, overwhelming the camera and causing the image to drop out. What happens is you see a sort of snow on the camera, all sorts of sparkles going by, and that's the particles accelerated by the coronal mass ejector hitting the actual camera on SOHO. If caught off guard, solar storms can harm astronauts, exposing them to the same amount of radiation in seconds that we receive on Earth in a year. So if we're going to send astronauts back to the moon and to Mars, it becomes very important to be able to determine when these coronal mass ejections and storms are going to occur. The charged particles embedded in these coronal mass ejections are dangerous. That's a lot of radiation that would hit an astronaut. Astronauts and satellites aren't the only potential victims of solar storms. The particles blasted towards Earth can interact with our magnetic field, occasionally wreaking havoc. When this material comes smashing into the Earth's magnetic field, it causes it to ring almost like a bell. And when you have a magnetic field and when that magnetic field moves, physics tells us it's going to create currents. And so electrical currents will be created in the outer atmosphere of the Earth. And these electrical currents can cause all sorts of disturbances. The currents create problems for satellites orbiting the Earth. They disrupt global positioning systems. They can interfere with communications equipment, causing radio blackouts and knocking out mobile phone systems. These mass ejections can send so many charged particles toward the Earth that some of them make it through the Earth's magnetic field and even reach power stations here on Earth, causing surges of electrons and power outages and short circuits and things like that. In extreme situations, solar storms cause excessive radio interference and increased levels of radiation, requiring planes flying near the poles to be rerouted. But as powerful as the storms were in 2003, they're no match for what astronomer Richard Carrington saw in 1859, a super flare. The super flare of 1859 was incredible because prior to this event, we didn't even know that flares existed. Carrington saw this huge bright flash on the sun with the unaided eye. And in order for him to see that, it had to have been a super huge, huge flare. There were reports of telegraph lines running without being powered. We probably won't see another one that intense in our lifetime, although it's hard to say for sure. The sun has thrown us some surprises. If a similar storm were to strike today, one recent estimate projects 130 million people would lose power, possibly for months. Most of the electrical infrastructure, power grids around the world would be knocked out. A lot of the transformers would be overloaded. Having the large portion of the population with no power for many, many months can cost huge amounts of money. People have estimated that it would be upwards of $2 trillion. We won't know unless it actually happens. And the more warning we get, the more we can do to reduce the economic impact, which is one of the reasons why we're studying the sun. Scientists are a step closer to being able to predict these storms since the launch of the Solar Terrestrial Relations Observatory, also known as STEREO. This pair of probes now give scientists the ability to see the sun in 3D. So now when one of these coronal mass ejections travels towards us, we're actually looking at the side view. And so we can see how fast they're traveling. We can see how they're evolving the structure. In 2011, the STEREO probes will reach their ideal vantage point, opposite sides of the sun, giving NASA a 360-degree view, allowing them to see what is coming from the far side of the sun before it impacts Earth. And so for the first time, we're going to have a complete view of the sun all the way around. So this is going to allow us to see everything that's happening on the sun at the same time, and this will lead us again into a better ability to predict these types of storms. But as dangerous as solar maximum can be for its increase in space weather, the sun's solar cycle counterpart and calmer period, solar minimum, may come with its own dangers. When there are a low number of sunspots on the sun, the climate here on Earth can actually cool a little bit. 2008 saw the fewest number of sunspots in nearly a century, with a total of 266 sunspot-free days. In 2008, we were at sunspot minimum. But by now, we expected to be climbing out of that sunspot minimum, and we're not. So this could mean that this particular sunspot minimum is more protracted. Scientists believe that past protracted minimums have had a chilling impact here on Earth. Now, every once in a while, the sunspot activity cycle seems to just go away or become much diminished. There was such a period around 1650 to the early 1700s. There were only about 50 sunspots recorded when normally in the same time frame there are tens of thousands. So it was a really low, low period of sunspots. It was called the Maunder minimum. The sun was in a quiet state. And that was associated with lower than normal temperatures here on Earth. Europe experienced sort of a mini ice age during those few decades. Whether or not this current minimum will be protracted enough to have such a large impact on Earth won't be known for years. But another measure of solar activity, the solar wind, appears to be waning. And that could impact Earth tomorrow. Bathed in the sun's atmosphere, Earth is shielded from deadly cosmic rays. And while the sun's power protects us, it can also harm us. Life on Earth survives this close to its star thanks in part to its ozone layer. But what would happen if the ozone layer were gone? If Earth lost much of its ozone layer, ultraviolet radiation from the sun would penetrate through the atmosphere and reach the Earth's surface. The sun's massive amounts of ultraviolet rays would quickly eliminate most basic elements of the food chain, wiping out plants and then animals. If we are bathed in huge amounts of ultraviolet light, eventually the life on the Earth would die. But what could cause such a catastrophic collapse of the ozone layer? Something the sun is supposed to protect us from. A gamma ray burst. Gamma ray bursts are intense, brief flashes of the most energetic kind of radiation known, gamma rays. The most powerful events in the universe. In seconds, they give off the same amount of energy that the sun will emit in its entire life. They occur when certain large mass stars die or even collide. They can be generated from very extreme processes such as large mass stars collapsing into black holes. They occur somewhere in the sky roughly once per day and they come from very, very far away. Most of them are billions of light years away. But just 8,000 light years away, deep within the Sagittarius constellation, buried in a pinwheel-like formation, looms a potentially ticking time bomb. WR104. Two stars locked in a cosmic dance, spinning a full rotation once every eight months. But one of these stars is on the verge of going supernova and emitting a gamma ray burst. Now one of these two stars is a very massive star that might someday form a gamma ray burst. And its beam might hit the Earth. If the high energy beam from a gamma ray burst were pointing directly at the Earth, it could spell real danger. The radiation from the gamma ray burst would be so intense, very short, on the order of 10, 20 seconds, that this would set up a chain of events which eventually would deplete the Earth of maybe 50 or more percent of the ozone layer. Scientists have speculated that a nearby gamma ray burst caused an ancient extinction on Earth millions of years ago. At the time, there was only sea life that existed. And even though the sea life deep beneath the sea wouldn't be directly affected by the UV radiation, the plankton and the life on near the surface would die off, and therefore the food chain would be affected. The threat is heightened even further by something scientists have witnessed over the past few decades, a 20 percent decrease in the power of the sun's solar winds. The solar wind is the steady emission of particles from the sun. They carry the magnetic field that is in the solar corona out into space. It exists even when there are no coronal mass ejections or solar flares. The solar wind continues way out beyond the orbit of Pluto and has actually blown a bubble in interstellar space. Now that's a bit of a protective bubble because the magnetic fields protect us from charged particles coming from outside. Normally, solar winds stream off the sun in all directions at speeds of one million miles per hour. Pulling the sun's invisible magnetic field along with it, they form the solar system's defense against intergalactic intrusion, the heliosphere. The heliosphere is the very boundary where the solar wind hits intergalactic space. So it's this shell that's surrounding the sun and the solar system where it protects us from intergalactic winds here on Earth. Recently, scientists have learned that the heliosphere is shrinking and getting weaker. The solar wind pressure has been measured to be decreasing over the last 25 years. In fact, the heliosphere, where the solar wind pressure is extending out to, has actually shrunk a bit. A weaker heliosphere increases the possibility that Earth will be exposed to harm from intergalactic cosmic materials. So if there's less solar wind, then the heliosphere itself is going to shrink. That makes it easier for more cosmic rays to enter into the solar system. Already, the amount of high-energy electrons, a small but telling aspect of cosmic rays around Earth, has jumped in number by 20 percent. Looks like the cosmic ray electrons have increased, and you would expect that. If the solar wind has decreased by 20, 30 percent over the last 15 years, the bubble will have gotten smaller, and you expect an increase in galactic cosmic rays. The good thing for us is that we live on a planet with a thick atmosphere and a magnetic field. So we have two types of shields that protect us. But that could change when WR104 emits its gamma ray burst, possibly upsetting the balance of sun and Earth, a balance that may already be in jeopardy because of something the sun did billions of years ago. Over billions of years, the sun and the Earth have developed the perfect balance for life to thrive. Sitting in the Goldilocks position of the solar system, not too hot and not too cold, the sun gives us just enough light, just enough heat, and just enough energy to fuel our planet and our lives. The sun drives everything on the Earth. The sun is the energy source of the Earth. So all of the energy that's given off by the sun heats up the Earth. This drives weather. On a larger timescale, this drives climate. So basically the sun is the energy source. It's the battery that drives the whole Earth environment. Plants harness the sun's energy through photosynthesis, creating carbohydrates. People and animals consume these carbohydrates, converting them into energy we can use. Even the fossil fuels that power our lives were created by the sun. But our increased use of fossil fuels seems to be upsetting the balance between the sun and the Earth. Since all living material gets its energy initially from the sun, the sun is the source of the fossil fuels, whether it's trees, whether it's other things that have been trapped in the rock layer and then squeezed and slowly over millions of years made into the hydrocarbons that we know them as. And we then harvest and use those from underground. The fossil fuels that we burn today unleashed the sun's energy from millions of years ago, overwhelming the balance struck between our planet and its nearest star. If we burn all this, we will change the atmosphere unrecognizably, long before we get to a point when we're actually running out of the resource itself. Already we have seen the effects of too much solar energy in the rise of global temperatures. The release of millions of tons of ancient solar energy stored in fossil fuels has amplified the necessary and natural process called the greenhouse effect. Many people think that the greenhouse effect is a bad thing. Well, in fact, it's not. It keeps the Earth warm. Without the greenhouse effect, Earth's oceans would be frozen solid. What is bad is too much of a greenhouse effect. If there's too much carbon dioxide and water vapor and methane in the Earth's atmosphere, then those gases trap too much of the sun's radiation, elevating Earth's average temperature, leading to global warming. Now that can cause a melting of the polar caps and a rise in the ocean levels, leading to just a calamity on Earth if it happens too quickly. Not only will our atmosphere continue to trap more heat, it could start to decay. Continued use of fossilized solar energy will allow in undesirable amounts of radiation from our sun. Right now, our ozone layer prevents the majority of the sun's ultraviolet radiation from reaching Earth, while allowing just enough sunlight to give us what we need to survive. Sunlight interacting with our skin produces vitamin D, which is a very useful vitamin. Vitamin D can protect us from a number of diseases, including the bone disorder osteoporosis and heart disease. But here, too, a balance has been struck. Too much sun can alter our DNA, causing skin cancer. Maintaining the equilibrium between sun and Earth that allows life to thrive will require using less of the sun's ancient energy and more of the energy it delivers on a daily basis. After all, the sun's energy output is estimated to be 386 billion billion megawatts, meaning in 15 minutes, our star radiates as much energy as all life on Earth consumes in one year. Tapping this power source has been the goal of scientists for decades. For sheer size, a solar satellite would be unprecedented. A structure 35 to 40 square miles covered with solar cells, able to capture the sun's energy 24 hours a day and beam it to Earth. NASA has yet to achieve a goal on that scale, but their work with solar technologies in space has advanced technology here on Earth. The history of solar cells is essentially a technology that came back down to Earth from space. When we first started to work on the Apollo and Mercury and Gemini programs, we needed power plants in space. Solar cells were a natural way to do that. Currently, we have two ways of directly harnessing the sun's energy. Solar thermal, which converts the sun's energy into heat by concentrating it enough to drive turbines, and solar panels, which use silicon-based technology to directly convert the energy from above into electricity. We can indirectly tap into the sun's power through wind turbines, capturing the energy produced by the weather the sun helps create. These technologies are constantly being improved. But some of the most interesting new science is coming from a very old process, photosynthesis. There's some really exciting opportunities as we move from the world of semiconductor solar cells to organic ones. Attempting to mimic Mother Nature, scientists have been able to create electricity from something found at the farmer's market, spinach. There's organic molecules in spinach in all green plants, but spinach happens to have a very convenient one where you can harvest that peptide, that molecule. Researchers were then able to put that peptide into a kind of solar sandwich, placing it between two electrically conductive materials. And when it's exposed to sunlight, it will circulate electrons, which is current, which is electricity. So these organic molecules can actually become little solar cells. In order to maintain the balance between Earth and our nearest star, it's become clear we must focus on finding ways to fuel our lives with the energy the sun supplies today. After all, the promise of solar energy is that for as long as the sun shines, its power can be ours. But what will happen when its power becomes too plentiful? The elements that make up the sun, the Earth, and even humankind all come from one place, stardust, the remains of stars that lived billions of years ago. And just as those stars died, so too will our sun. In about five billion years, the sun will pretty rapidly become much more powerful, much brighter, and much bigger. The sun will reach a stage where it has burned through all of its hydrogen. And once that happens, it will start to burn through all of its helium. The sun will start to expand as it reaches a stage called a red giant. As it expands, it will start to expand into much larger size and fill the inner solar system. The orbits of the planets themselves will actually expand outward as well, because it's not as massive. During that stage, some instabilities, which I call cosmic burps, will cause the sun's outer atmosphere to be gently ejected. The outer layers of the red giant will just keep drifting off at some slow rate. The hot inner layers of the sun will ionize that cloud of gas surrounding it and cause it to glow. So our sun will be surrounded by these glowing clouds of gas. They will form what's called a planetary nebula. They're beautiful shapes. Some are just purely round, but some have been distorted into other shapes. They've come off non-symmetrically from the star underneath. What will remain is the contracting core of our sun. And it won't produce any new energy through nuclear reactions, because all the nuclear reactions will have stopped. So it will continue contracting and slowly fading with time. It's very similar to the process that creates, say, supernova. But our sun is not big enough, doesn't have enough stuff to actually create a supernova. So its final stage will be this object we call a white dwarf star. What remains is this little, relatively small white dwarf star. And it is a very quiet, what we call happily retired star. It'll be about the size of the Earth. It won't get any smaller. And it'll sit around as this very highly compressed rock forever. It'll just liberate its energy, growing ever colder and dimmer with time, until finally it just fades from view. The death of the sun will have catastrophic effects on the solar system. If the massive expansion doesn't swallow the nearby planets, it will likely change their orbits and superheat them, including Earth. Earth's surface will be fried to a crisp. The Earth is probably going to get baked one way or the other. I mean, imagine the sun being one or two hundred times brighter than it is right now. Imagine how much the Earth would be heated. It would not be a pleasant place to be. It actually may get baked before the sun completely dies. Because the sun will get hotter, even before it becomes a red giant and gets as large as the orbit of the Earth. It'll get warmer and at some point the Earth will get hot enough so that water will boil. So the oceans will evaporate away and all of life as we know it will cease to exist. If there's anything left of the Earth, the sun will shrink down to a white dwarf. The Earth will, instead of heating, freeze. This will not be a pleasant place to live. But that's billions and billions of years from now. We've only had rockets in space, satellites, for 50 years or so. Now we're talking billions. So clearly we'll be able to travel around the solar system at the very least to go to places that will be at the temperature that the Earth is now and we'll be able by that time to go to more distant solar systems. So I don't spend a lot of time worrying about what's going to happen to the sun in 5 billion years. The sun gave us our life and it will eventually take it away. And though the Earth will die, it and everything on it will in some part live on. The stardust that gave Earth and all of its inhabitants life will one day become the stardust that gives rise to a new generation of planets, stars and life. So indeed we are stardust. The carbon in your cells, the oxygen that you breathe, the calcium in your bones, the iron in your red blood cells. All those elements were created deep inside stars through nuclear reactions. And because some of those stars explode, we eventually are able to exist. The realization that we came from the stars is what we need.