"In the beginning," "There was darkness," "And then, bang..." "Giving birth to an endless" "Expanding existence" "Of time, space, and matter." "Every day, new discoveries" "Are unlocking the mysterious," "The mind-blowing," "The deadly secrets" "Of a place we call the universe." "Energy, the ultimate" "Galactic transformer," "Forever morphing" "From one form to another." "It powers our planet" "And everything else" "In the universe." "But what exactly is it?" "Where did it all come from?" "And how do we get more?" "Energy can be neither created" "Nor destroyed." "It can only be transformed" "From one type to another." "This transformation sometimes" "Goes to the extremes" "In objects like black holes." "Could a future civilization" "Harness that power?" "What a neat way" "To get rid of your garbage" "And solve your energy crisis," "All at the same time." "And what if" "Our universe's energy" "Was transferred" "To another place in time?" "What if a passageway" "Opens up to a parallel universe" "And bleeds off" "Some of that energy?" "Life wouldn't be able" "To withstand that." "This is the story of energy," "From the big bang" "To your own backyard." "Charge up your engines," "As we follow the trail" "Of extreme energy" "In the universe." "The Universe - 4x12 November 10, 2009" "Energy is a cosmic chameleon." "It drives our universe" "By constantly changing form." "It powers acceleration," "Expansion," "And apocalyptic impacts." "Everything in our universe" "Is energy." "You're energy." "Trees are energy." "The dirt is energy." "And even the empty space" "Between the stars is energy." "But where does all this" "Ever-changing energy come from?" "All of the energy" "We see around us every day" "Actually comes" "From the very beginning" "Of the universe," "Billions of years ago." "But when you see a car accident" "On the highway," "That's a very energetic event." "Cars get mangled." "There's a big noise." "But where did the energy" "Come from?" "Well, the energy" "Comes from the energy of motion" "Of the two cars" "Before they crash." "But where do the cars" "Get their energy?" "From gas, a fossil fuel" "That gets its energy" "From plant life" "That was living" "Millions of years ago," "Plant life that got its energy" "From the sun," "Which gets its energy" "From nuclear reactions" "Inside the core." "Those nuclear reactions" "Get their energy" "From the particles" "That were created" "At the time of the big bang." "All the many forms of energy" "We see around us" "Come from the big bang..." "The beginning of the universe." "The origin of all the matter" "And energy in the universe" "Is really the big bang," "The creation" "Of the universe itself." "Now, we think that, in fact," "The big bang" "Was the sudden expansion" "Of a very small amount of space" "Into a very large space," "Driven by a weird kind" "Of an energy." "We're not sure" "What type of energy" "Kick-started the big bang." "But whatever it was," "In one brief instant," "It produced all the energy" "Past..." "Present..." "And future." "This is one of the most" "Important and surprising aspects" "Of energy." "In black holes," "Exploding stars" "Or even power plants on earth," "It can be neither created" "Nor destroyed." "It can only be transformed" "From one type to another." "If the laws of physics" "In the universe" "Never changed in the past" "And don't change in the future," "Then no energy" "Can be created or destroyed," "It can only be transformed." "Transformation is the key" "To how energy works." "The universe is filled" "With many forms of energy," "Such as light," "Sound," "Thermal," "And chemical." "The most common among them" "Is potential energy," "The stored or pent-up energy" "Of an object..." "And kinetic energy," "The movement of an object." "And all forms of energy" "Are constantly converted" "Into other forms of energy." "When you fire a gun" "At a target," "You might think that once" "The bullet hits the target," "That that energy is gone." "But it's not actually gone," "It's actually" "Just been transformed" "Into another type of energy." "The chemical potential energy" "In the gunpowder" "Has been converted" "Into the kinetic energy" "Of the bullet," "Sound waves, heat," "And whatever energy gets" "Transferred into the target," "Maybe causing it to move" "Or explode." "even the human body" "Is a fine-tuned," "Energy-transforming machine." "A good way to think" "About how we transform energy" "Is eating." "Humans eat a certain amount" "Of calories every day." "And th whatever" "Physical activity they do," "They do that and burn off" "That certain amount of calories." "And you have to continue to eat" "Because you continue" "To be active" "And burn off calories." "Incredibly, Albert Einstein" "Realized that energy and matter" "Are really the same thing," "And one can be converted" "Into the other." "That's the meaning" "Of his famous equation, e=mc2." "Einstein came up with a way" "To explain that everything" "In this universe is energy." "Matter is energy." "If you weigh, say, 100 kilograms," "That's your mass." "And if you take that" "And you multiply that" "By the speed of light" "And then multiply that" "By the speed of light," "Then you get" "The amount of energy" "That exists within your body." "Actually about" "A thousand times more energy" "Is in your body than there was" "In the largest nuclear weapon" "Detonated by mankind." "Objects may have" "The same amount of energy," "But that doesn't mean" "They have the same amount" "Of power." "The key ingredient" "Is how quickly" "The energy is released." "Power is equal to energy" "Per unit time." "So even something" "With a really small amount" "Of mass, like, say, this cupcake" "Would have the equivalent energy" "Of about a million tons of TNT." "We all know that cupcakes" "Don't spontaneously explode" "And emit a million tons of TNT." "If I eat a cupcake," "It only gives me" "About 200 calories of energy" "Over several hours." "Whereas if I have" "A stick of dynamite," "That same amount of energy" "Would be released in," "Say, a millionth of a second." "So the TNT has much more power" "Even though it has" "The same amount of energy." "If you have a pizza" "And you're gonna eat that pizza," "Say you eat 1,000 calories" "Worth of pizza." "That might be a big meal," "But your body has to convert" "The matter of that pizza" "Into that 1,000 calories," "And it's really" "Not that efficient." "Take, for example, the same mass" "In TNT or dynamite." "When you light the fuse on that," "You get way more energy." "All of the energy" "We use here on earth" "To feed our bodies," "Power our electronic devices," "And light our homes" "Ultimately comes" "From outer space." "Some of the most extreme" "Transformers of energy" "Are stars," "Including our sun." "At any given second," "The sun is putting out" "About 10-to-the-26 watts." "A 1 with 26 zeros after it." "That's like 400 billion" "Nuclear weapons" "All in one second." "That's how much energy" "We're getting from the sun" "At any given second." "Stars like our sun" "Produce many forms of energy," "But it all began with gravity." "All gravity means" "Is that we've observed" "That all matter falls" "Towards all other matter." "And it's interesting" "That you can use gravity" "To transform energy" "From one type to another." "If I hold a rock up here," "It has a certain" "Potential energy." "And then I let it go." "Gravity turns" "That potential energy" "To kinetic energy" "Until it hits the ground." "Over 13 billion years ago," "Gravitational energy" "Gathered up dust and gas" "To form the first stars." "Once a star is formed" "Through gravitational energy," "It then produces nuclear energy." "Stars are powered" "By nuclear fusion." "So this is when you take" "Multiple hydrogen atoms" "And you smash them together" "To produce heavier elements" "Like helium or carbon" "And oxygen and nitrogen." "When this" "Fusion process happens," "The enormous energy" "Of what's called" "The strong nuclear force" "Is liberated," "And that is what lights up" "The star." "Nuclear fusion within stars" "Like our sun then produces" "A form of energy called" "Electromagnetic radiation." "These are oscillating waves" "Of photons," "Or particles of light." "On earth and in space," "Electromagnetic radiation" "Consists of a spectrum" "Of energy." "On the low end are radio waves" "With low frequencies" "And very long wavelengths." "On the high end" "Of the electromagnetic spectrum" "Are gamma rays" "With high frequencies" "And extremely short wavelengths." "Each photon" "Of electromagnetic radiation" "Takes up to 150,000 years" "To actually get" "From the center of the sun" "To the surface," "Before it can escape" "And head towards earth." "Luckily for us," "Our atmosphere blocks most" "Of the dangerous wavelengths" "Of electromagnetic energy," "Which are ultraviolet," "X-rays, and gamma rays," "From reaching our world." "But it allows visible light," "Infrared, and radio waves" "To pass through." "Light and infrared energies" "Are absorbed" "By landmasses and oceans" "And then converted" "To heat energy." "The sun" "Is continually emitting" "Electromagnetic radiation" "Which is giving us heat energy" "Here on earth and in space." "Humans have found" "Clever ways to harness" "The energy of the universe." "We've learned to transform" "Solar radiation into heat" "As well as electrical energy." "One of the most" "Common technologies we use" "To harness the power of sunlight" "Is solar panels." "Solar panels are usually" "Made out of semiconductors" "Which are light sensitive." "So when sunlight" "Hits the silicon solar array," "It generates charges." "Those charges are then swept out" "Of the semiconductor material" "And that generates" "An electrical current." "Electricity can be generated" "From one solar cell" "Or a solar farm" "Holding 550,000 solar panels." "And those currents" "Can charge everything" "From a home to a hot sports car." "Whoo!" "Ha ha!" "Stars are awesome" "Transformers of energy." "Here on Earth" "We're constantly bombarded" "With the sun's" "Electromagnetic energy" "In the form of light." "In turn, we convert it" "Into other energies to power" "Some of the st unlikely things" "In our everyday world." "We're here" "At Tesla motors today to see" "How electromagnetic energy" "Can be converted" "Into mechanical energy" "Which is used to power" "This high-end sports car here." "All it takes" "Is simple electricity" "From your average wall socket." "So if we plug the car in," "Like so," "We're now taking energy" "From the wall socket" "And we're using it" "To charge up the car's battery." "And the battery," "Located right here," "Is used to run" "The car's electric motor." "So the computer inside the car," "Which is right here," "Takes energy from the battery" "And uses it to turn" "The single electric motor" "Which powers the car" "At astonishing speeds, actually." "So you can imagine," "If you had, say, solar panels," "On top of your house" "And you were to plug the car in," "Your car would literally" "Be running off of sunlight." "All right, here we go." "Whoo!" "Ha ha!" "And transforming sunlight" "Into electricity" "Has its advantages." "Electric vehicles accelerate" "Faster than gas vehicles" "Because electric motors" "Provide full torque immediately" "While gas engines" "Have to rev up." "Can do 0 to 60 in 3.9 seconds, and it makes it faster than just about any other production gasoline car there is." "This just illustrates the great power of electromagnetic energy." "Isn't science fun?" "Our sun is responsible" "For fueling almost everything" "In our world" "By transforming its energies" "From one useful form" "To yet another." "Green plants" "Convert solar energy" "Into chemical energy" "Through photosynthesis," "Which feeds all living things," "Including humans." "I get energy" "From my cornflakes" "Because the corn in the flakes" "Got their energy" "From photosynthesis of sunlight" "That converts sunlight" "Into sugar... carbohydrates." "All kinds of molecules" "Have bonds between the atoms" "In the molecules" "That when they break," "Release energy" "And give us the energy" "That we need when we exercise." "And this life cycle of energy" "Doesn't end here." "Over millions of years," "The decomposed remains" "Of dead plants and animals" "Are compressed underground" "And converted into fossil fuels." "They come in many forms" "Including coal," "Petroleum," "And methane." "When we burn oil" "Or natural gas," "We're really liberating" "The energy from sunshine" "That was collected by plants" "Thousands, tens of thousands," "Hundreds of thousands" "Of years ago" "And stored underground" "In fossil fuel repositories." "Fossil fuels are considered" "Non-renewable resources." "This doesn't mean their energy" "Is completely destroyed" "But that they can't be" "Replenished naturally" "In a short period of time." "When we talk about" "Non-renewable energy sources," "Like, say, burning fossil fuels," "We don't mean that energy" "Is gone from the universe." "What we mean" "Is that that energy source" "Has been transformed into a form" "That's no longer useful," "Like, say," "For example, waste heat." "The sun provides" "Much of the energy" "Essential for our survival," "But this energetic powerhouse" "Can also produce" "Lethal energies." "NASA's swift observatory" "Witnesses a frightening event." "The largest stellar flare" "Ever observed releases energy" "Equal to 50 million trillion" "Atomic bombs." "The killer flare fires energy" "In the form of x-rays" "That would obliterate" "Most life on earth" "If it came from our sun." "Fortunately for us," "This radiation" "Came from the star IL Pegasi," "Which is 135 light-years away." "Even so, this incident" "Illustrates the deadly energy" "Being released from stars," "Including our sun." "A solar flare" "Is a relatively sudden release" "Of a tremendous amount" "Of energy." "This energy comes" "From magnetic energy." "A bunch of tangled" "Magnetic fields s suddenly release" "This radiated energy." "It can be thought of" "As a bunch of stretched," "Twisted rubber bands." "That's the magnetic field lines." "And eventually, they just snap" "And that snapping" "Releases the energy" "And channels it outwards" "From a relatively" "Localized region" "On the sun's surface." "Solar flares can reach" "As much as 15 million degrees" "Because it's converting" "Magnetic energy" "Into heat energy," "And massive amounts" "Of magnetic energy" "Into that heat energy." "Solar flares" "Can occur several times a day" "During high solar activity." "When they're erupting," "Each flare can produce" "As much thermal energy" "In a few minutes" "As the entire sun produces" "In one second." "If some of the high-energy" "Charged particles" "Generated by solar flares" "Are headed in our direction," "They'll be deflected" "By another energy source," "The earth's magnetic field." "It's produced" "By electric currents" "That flow in its molten core." "These currents" "Are hundreds of miles wide" "And move at thousands" "Of miles per hour" "As the earth rotates." "This powerful magnetic field" "Passes through the earth" "And enters space." "The earth's magnetic field" "Stops or deflects" "Most of the charged particles" "That come at us from the sun" "Or from interstellar space," "And this is a really good thing." "Because it would be really bad for life on Earth if a lot of these very high energy particles made it to the ground and hit our bodies." "A massive star" "Can send off flares" "For 10 billion years." "And when the star" "Nears death..." "It doesn't mark the end" "Of the transformation" "Of extreme energy." "In fact," "It's just the beginning." "Once you have" "The beginning of a star" "Where it does start" "The nuclear fusion," "Then the nuclear fusion" "Continues on" "And it will burn" "Until all the hydrogen" "Is used up, basically." "Deprived of" "The nuclear energy" "To support itself," "A massive dying star" "Finally collapses..." "Igniting a supernova explosion." "A supernova can radiate" "As much energy" "As the sun will emit" "Over its entire life span." "Stars exist in a balance" "Between energy" "From a nuclear furnace" "On the inside" "And gravitational pull" "Of all the mass of it" "Collapsing in on itself." "And at some point" "When the nuclear furnace" "Starts to die out," "Gravitational attraction" "Becomes the final winner" "Of that conflict." "It collapses and it emits" "A bunch of light," "And it's due to gravity" "Overcoming the nuclear furnace" "In the star." "Now it's important" "To keep in mind" "That the energy" "Of an exploding star" "Isn't simply created" "Out of nothing." "Again it's energy" "That's transformed" "From one type to another." "The core of a massive star" "Collapses," "Releasing a lot of gravitational" "Potential energy." "That energy then is channeled" "Into neutrinos," "Into the kinetic energy" "Of the ejected material," "And into the visible energy" "That we observe." "Supernovas are one" "Of the most explosive" "Transformers of energy" "In space." "However, 99% of the energy" "Released during a supernova" "Is converted into something" "That's actually invisible" "Strange, ghostly particles" "Called neutrinos." "Neutrinos are nearly massless" "Energetic particles" "That move at almost" "The speed of light" "And pass through matter" "Virtually undisturbed." "Every second," "More than 50 trillion" "Solar neutrinos" "Pass through the human body" "Without us knowing it." "The likelihood of one of them" "Interacting with a particle" "In your body is so low" "That you don't notice it." "And even if it did happen," "It would be just" "A little blip of energy" "That your body gets," "Which is much less significant" "Than all the other" "Blips of energy it gets" "From other kinds of particles" "That are running into you," "Such as light or radiation" "That's naturally produced" "From the earth." "Neutrinos" "Were once impossible to detect." "They traveled" "Right through the earth" "And exited back into space" "Unnoticed." "But in Hida, Japan," "Over 3,000 feet underground" "Lives the super-k observatory." "It houses a massive" "Stainless steel tank" "Containing ultra-pure water." "It's been discovered" "That when neutrinos interact" "With the electrons" "Or atomic nuclei in water," "They produce a charged particle" "Which creates a flash" "Of ultraviolet light." "As that particle" "Streams through the water," "It actually gives out" "A tiny blip of radiation" "That can be measured" "By these little light detectors" "Which then SS," "That's a neutrino." "Could these" "Stealthy particles" "Be a source of energy" "Here on earth?" "That's what Alan k." "From Chicago, Illinois," "Wanted to..." "Interesting question, Alan." "It turns out that neutrinos" "Are incredibly hard to detect." "So we probably can't harness" "The sun's neutrino energy." "Also we don't really want to" "Because only about 3% of the sun's energy" "Is in the form of neutrinos." "It's much easier" "To harness the sunlight" "And there's much more of it." "Neutrinos may not be able" "To alleviate our energy crisis," "But lurking in each galaxy" "Exists a ravenous beast" "That just may be" "The most fuel-efficient engine" "In outer space." "The ability to convert energy" "From one form to another" "Has inspired innovative ideas" "For future space colonization." "Super massive black holes" "Reside in the centers" "Of most galaxies," "Including our milky way." "They can store" "And unleash the energy" "Of billions of supernovas." "When the super massive" "Black holes were forming," "A tremendous amount" "Of gravitational" "Potential energy was converted" "Into radiated light" "And other forms of energy, 'cause you had a lot of material" "Get compressed" "Into a very small volume." "It had to give up" "A lot of energy." "A super massive black hole" "Is 10 billion suns' worth." "That means" "It has the equivalent mass" "Of 10 billion stars," "Just all packed" "Into a very tiny space." "NASA's Chandra" "X-ray telescope unravels" "A puzzling mystery about" "The transformational energies" "Produced by a black hole." "It detects" "A super massive black hole's" "Powerful gravitational energy" "Drawing in a nearby star." "As the gluttonous beast" "Gorges on the star," "It spins wildly," "Sometimes approaching" "The speed of light." "This kinetic energy" "Twists up the gas and debris" "Falling into the hole" "To form a fast-spinning" "Rotational accretion disk." "This rotating material" "Is then released" "In powerful jets." "This extremely" "High-energy material" "Spiraling around the black hole" "Creates a very large" "Magnetic field." "Now some of the material" "Actually follows" "Those magnetic field lines" "And gets shot out along them," "Forming a big, powerful jet" "That's sort of like" "A blowtorch." "Recent computer simulations" "Have shown" "That if the extreme kinetic" "Or rotational energy" "From a black hole's spin" "Could be harnessed..." "These black monsters" "Could become the ultimate" "Galactic batteries." "Wouldn't be great if you have a spinning black hole, just spinning there, out there in space, and you build this thing in orbit around it and extracts energy from that." "And it would give you a huge amount of energy to fuel your super advanced civilization." "And black holes" "May not only be responsible" "For generating different" "Forms of energies." "They may serve a dual purpose" "As a galactic recycling center." "One might imagine" "An advanced civilization" "Living near" "A spinning black hole." "It could send garbage trucks" "Close to the spinning black hole" "That would dump their garbage" "At the appropriate time." "Those trucks would then emerge" "From the vicinity" "Of the black hole" "With more energy of motion," "Kinetic energy," "Than they had going in." "Those trucks could" "Then hit a turbine," "Like a windmill," "Drive the turbine," "Generate electrical energy" "And thus light up their cities." "What a neat way" "To get rid of your garbage" "And solve your energy crisis" "All at the same time." "Black holes may energize" "A future space colony." "But scientists are now" "Discovering that the energy" "From whirling black holes" "May be transforming" "Into something dangerous." "Cosmic rays are highly energetic" "Charged particles." "Contrary to their name," "They're not rays" "Of light energy." "Rather, they contain" "Very large amounts" "Of kinetic energy," "Which can cause deadly effects." "Cosmic rays are a way more energetic than anything we've been able to produce on Earth." "Hundreds of thousands of times more energetic." "The most energetic" "Cosmic rays" "Are called ultra-high energy" "Cosmic rays." "They travel" "At close to the speed of light" "With ever-increasing brightness." "An ultra high-energy" "Cosmic ray" "Has about as much energy" "As a tennis ball" "Hit at 100 miles an hour." "That's how fast" "The professionals get them going" "On court." "That doesn't sound" "Like a lot of energy," "But actually there are trillions" "Of particles making up" "A given tennis ball." "And what's going on is that" "You've taken all of that energy" "And put it into" "One subatomic particle," "And that's what" "A cosmic ray coming in" "Through our atmosphere is like." "And so that's a lot of energy" "For a single particle to have." "New evidence suggests" "That galaxies" "Known as active galactic nuclei" "May be the source" "For these ultra-high energy" "Cosmic rays." "These are galaxies" "That have super spinning" "Super massive black holes" "At their cores." "Those are essentially" "Extremely powerful" "Generators of energy." "There are magnetic fields" "And electric fields" "All spinning around" "And throwing out particles" "At incredibly high rates," "Usually generated" "By a super massive black hole" "At the core." "And that sort of system," "Black holes especially," "Are able to produce" "Huge amounts of energy" "That can throw out" "These particles" "In all directions." "Ultra high-energy cosmic rays" "Have become" "One of the top health threats" "To interplanetary" "Space missions." "These charged particles" "Could hurtle" "Right through a spaceship..." "And penetrate astronauts" "Like tiny ballistic missiles," "Ripping apart DNA molecules" "And even killing cells." "A high-energy cosmic ray," "If it interacts" "With human tissue, can do damage" "To the DNA in that tissue" "And lead to a disruption" "Of the cell," "Maybe leading to cancer." "And cosmic rays" "May not only threaten" "Space travelers." "Every second," "Cosmic rays bombard" "Our earth's atmosphere." "Some even penetrate" "All the way through" "And rain down on our planet." "The key to cosmic rays'" "Transformational energy" "Is speed." "So even if it has a really tiny mass, like most cosmic rays, they've got enormous velocity." "So their kinetic energy can be really, really large." "When they strike" "The earth's atmosphere," "They collide with molecules," "Mainly oxygen and nitrogen." "This produces a storm of energy" "In the form" "Of ultraviolet radiation" "That cascades down" "On our planet." "Those cosmic rays are coming" "From outer space all the time, 24 hours a day," "Just impinging" "Upon the outer atmosphere" "And running" "Into the air molecules," "Then producing" "Showers of particles" "That we can detect here" "On the surface of the earth." "Fortunately for us," "One original ultra high-energy" "Cosmic ray spreads its energy" "Out to millions or even billions" "Of particles." "So its energy," "Originally in the form of x-rays" "And gamma rays," "Is so dissipated" "That it's no longer harmful" "To humans." "However, these cosmic rays" "Could cut off" "Your cell phone conversation." "These air showers," "As they're called," "Which are produced" "By the cosmic rays" "Hitting the outer atmosphere," "Those could affect electronics" "Here on the ground." "Our computers and cell phones" "And other devices" "That we use every day" "Are becoming" "More and more delicate" "As we miniaturize our circuitry," "And that actually makes it" "Much more sensitive" "To being disrupted" "By cosmic rays." "in every corner" "Of the universe, we witness" "The destructive nature" "Of energy in motion." "Yet, here on earth," "We generate" "A unique form of energy" "That comes from the creation" "Of our solar system." "Since the beginning of time," "Energy has been the universe's" "Long-standing magic act," "Constantly changing" "From one form to another." "One unique type" "Of extreme energy is the legacy" "Of our solar system's creation." "Geothermal energy" "Comes from the heat created" "In the earth's rocky core" "Which exists about 4,000 miles" "Below the surface." "Our solar system" "Was first formed" "About 4 1/2 billion years ago," "When a cloud of gas and dust" "Condensed to form the sun" "And all of the planets." "A small fraction" "Of that gas and dust" "Consists of radioactive elements" "Like uranium-238 and thorium." "When the earth condensed," "Some of those" "Radioactive elements" "Got collected" "Into our earth's interior." "As those elements slowly decay" "Over billions of years," "They heat up the interior" "Of the earth." "We can access this heat energy" "As geothermal energy." "Some areas" "Of the earth's surface" "Allow this geothermal energy" "To seep through," "Such as near plate tectonic" "Boundaries," "Volcanoes," "And geysers." "Geothermal energy" "Can be tapped" "Near plate tectonic boundaries" "Where this hot stuff comes up," "Produced by exploding stars" "Long ago that are radioactive" "And release their energy" "Over time scales" "Of billions of years." "Geothermal plants" "Around the world" "Harness heat energy" "From superheated reservoirs" "To create electrical energy." "High-temperature," "High-pressure water" "Is brought to the surface" "Where it enters" "A low-pressure chamber" "And flashes into steam." "The pressure created" "By this steam" "Is channeled through a turbine" "Which spins to generate" "Electrical power." "Once the steam" "Has exited the turbine," "It is either released" "Into the atmosphere" "As water vapor," "Or it cools" "Back into liquid water" "And is injected" "Back underground." "In almost all cases" "Until recently," "Geothermal power plants" "Have been either" "Near plate boundaries" "Or hotspot weak spots" "In the earth's crust" "Through which the hot magma" "Can come." "So since most" "Of the earth's surface" "Is not near a plate boundary," "It's been relatively difficult" "To tap into geothermal energy." "The best concentration" "And quality of geothermal energy" "Exists where there are" "High levels of tectonic" "And volcanic activity," "Like the ring of fire" "Which circles the pacific ocean." "But excavating close" "To plate boundaries is tricky." "To get a lot" "Of consumer energy" "Out of the geothermal energy" "Of the earth" "Really requires" "Digging quite deep" "To where the temperatures" "Are high enough that you get" "A lot of energy out." "The technological challenges" "For extracting geothermal energy" "For consumer use are huge." "You either need to harness" "A volcano or drill down" "Very, very deep into the earth," "Or cap the geysers" "At Yellowstone." "But this type" "Of thermal energy" "May not be exclusive" "To planet earth." "Io, one of Jupiter's" "Four main moons," "Has active volcanism," "Like earth." "But the thermal energy" "From its core is produced" "Not through the decay" "Of radioactive elements" "But rather through" "Tidal heating." "Io has an elliptical orbit" "Around Jupiter, so sometimes" "It's closer to Jupiter" "Than at other times." "When it's closer to Jupiter," "The tidal stretching of Io" "Is greater than" "When it's farther from Jupiter." "So as it orbits Jupiter," "Io sort of squishes" "Back and forth." "That gives rise" "To a lot of rubbing" "Of the interior rocks" "And they then release energy." "The interior gets hot," "Magma flows to the surface," "And you see a bunch" "Of erupting volcanoes." "So that can be thought of" "As a geothermal energy." "We certainly know" "That the inside" "Of Jupiter's moon, Io, is molten" "Because we see volcanoes there" "And that is the equivalent" "Of geothermal." "I say equivalent" "Because Geo means earth." "So, strictly speaking," "Geothermal" "Is earth's interior energy." "Planet Jupiter" "May not have a molten core" "Like its moon Io." "But the gas giant's hot interior" "Generates another form" "Wind." "The giant planets," "Jupiter and Saturn," "Have very windy atmospheres." "They are very stormy," "Not just because of heat" "From the sun," "But, in fact, largely" "Because of heat generated" "On the inside." "Their interior parts" "Are still contracting," "Releasing gravitational energy," "And converting it into energy" "Winds and storms." "This is another example" "Of the conversion of one form" "Of energy into another." "Some of the winds" "On the giant planets" "Can travel at immense speeds, 600 or even 700 miles per hour." "Now, most of them are only" "A few hundred miles per hour," "Which still is big" "Compared to even" "Big storms on earth." "But the fastest storms" "Can travel at 600" "Or 700 miles per hour." "That's really fast." "Earth also benefits" "From wind energy," "But its source doesn't come" "From its core, but rather," "Directly from space." "The source of energy" "That we see in winds on earth" "Is really solar heating." "The sun heats different parts" "Of the atmosphere" "By different amounts," "And that causes imbalances" "That allow the air to flow." "That's wind energy," "Mechanical energy" "Coming from the sun's" "Electromagnetic energy." "That wind energy" "Can then be used" "To drive a turbine," "Converting it" "Into electrical energy" "That lights our cities." "Energy has propelled" "The evolution of the universe" "Since its birth" "Over 13 billion years ago." "But now science has discovered" "A mysterious type of energy" "That just may be" "The cosmic grim reaper." "Throughout outer space" "Exists a phantom energy." "We don't know where" "This mysterious form originated," "But it's now believed" "That it could destroy" "Life on earth" "And maybe even" "The universe itself." "In the 1990s," "Astronomers used" "The Hubble space telescope" "And other observatories" "To measure the distances" "Of exploding stars" "In other galaxies." "To their shock, they noticed" "Something quite peculiar." "Recently, astronomers" "Have discovered by looking" "At the distances of supernovae" "That the universe is actually" "Accelerating apart." "It's not just expanding," "But it's actually accelerating." "Some mysterious energy" "Is driving the universe apart" "Faster and faster." "Astronomers realized" "That the expansion" "Of the universe" "Is speeding up with time" "Due to dark energy," "A strange form of energy" "That exists everywhere." "It accounts for almost 75%" "Of all mass and energy" "In the universe." "And it's one" "Of the big mysteries" "Of the universe." "It is, in fact," "The biggest mystery" "Of the universe in some sense," "Because dark energy" "Is the largest component" "Of the energy budget" "Of the universe." "Our current knowledge" "And understanding of dark energy" "Is very limited," "Even though dark energy" "Comprises almost 75%" "Of all matter and energy" "In the universe." "It would be similar to us" "Having only explored" "The landmass on the earth" "When the ocean comprises almost 75% of all of the surface" "Of earth." "We are just now starting" "To explore dark energy." "Scientists had once thought" "That gravitational attraction" "Would cause the expansion" "Of the universe" "To slow down with time." "The belief was that" "The universe was expanding" "From the big bang" "And that gravity" "Ought to be slowing" "That expansion rate." "And the big question" "At that time was," "Is gravity strong enough" "To pull everything" "Back together?" "But we got a surprise." "Gravity wasn't slowing down" "The expansion." "In fact," "When we observed carefully," "We discovered that the expansion" "Was accelerating." "While gravity binds planets," "Stars, and galaxies," "Dark energy appears to stretch" "The fabric of space and time," "Thereby pushing galaxies apart." "Recent observations have shown" "That dark energy is causing" "Our universe to expand" "At an ever faster pace." "Over the history" "Of the universe," "The relative amounts" "Of dark energy" "And regular," "Gravitationally attractive" "Matter and energy" "Have changed." "Early on," "Regular, gravitationally" "Attractive energy dominated," "And that's because objects" "Were close together." "There wasn't much dark energy" "In between them," "So its cumulative effect" "Was very small." "But as the universe expanded" "And galaxies got farther apart" "From each other," "The amount of space," "All of which was filled" "With dark energy, increased." "Let's suppose" "We model the universe" "As an expanding loaf" "Of raising bread," "Where the raisins" "Are the galaxies..." "They don't expand..." "And the dough is uniformly" "Filled with yeast." "That's like the dark energy." "Now suppose we continue" "To inject yeast" "Into the baking bread" "As it expands." "It'll expand faster and faster" "With time, 'cause there's" "More and more yeast." "It'll be accelerating" "In its expansion." "In a similar way, with time," "There's more and more" "Dark energy in the universe." "Thus, accelerating," "Speeding up its expansion." "If dark energy continues" "To speed up the expansion" "Of our universe," "We could eventually experience" "The big chill." "Clusters of galaxies" "Will spread thinner and thinner." "Galaxies will exhaust" "Their gas supply" "To form new stars" "And old stars will burn out." "The universe will become dark" "And insufferably cold." "In a universe" "That expands forever" "Or nearly forever," "Eventually, the sun" "And all the other stars" "Will burn out." "They'll use up" "Their nuclear fuel." "At that point," "There will be basically" "No source of energy" "For life on earth." "So life as we know it" "Will cease to exist." "But if this" "Grim scenario happens," "All the energy in the universe" "Won't disappear," "Because our energy budget" "Has been fixed" "Since the big bang." "However, the energy will become" "Impossible to access." "The energy" "Gets spread out so much" "And diluted to such an extent" "That it is no longer usable." "But there are other theories" "About the fate" "Of our universe's energy." "In the distant future," "Some propose" "Energy could be transferred" "To another place," "Perhaps another universe." "According to the laws" "Of physics," "Energy can't be created" "Or destroyed." "And all the energy" "That is within our universe" "Has always been here" "And will always be here." "But what if a wormhole" "Or something opens up" "To a parallel universe" "And bleeds off" "Some of that energy?" "It's possible that our universe" "Would start cooling off," "Because we're leaking" "At that point." "And I don't think" "That would be a good idea," "Because eventually the universe" "Would cool off to a point where" "Everything would freeze out" "And life wouldn't be able" "To withstand that." "We don't know" "What the far future holds" "For energy in our universe" "Or beyond." "But for the time being, it remains the violent yet vital and every changing component of our universe."