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  • All across the immense reaches of time and space, energy is being exchanged, transferred,

  • released, in a great cosmic pinball game we call our universe.

  • To see how energy stitches the cosmos together, and how we fit within it, we now journey through

  • the cosmic power scales of the universe, from atoms nearly frozen to stillness.

  • To Earths largest explosions. From stars colliding, exploding, to distant centers of power so

  • strange, and violent, they challenge our imaginations. Today, energy is very much on our minds, as

  • we search for ways to power our civilization and serve the needs of our citizens.

  • But what is energy? Where does it come from? And where do we stand within the great power

  • streams that shape time and space?

  • Energy comes from a Greek word for activity or working. In physics, it is simply the property

  • or the state of anything in our universe that allows it to do work. Whether it is thermal,

  • kinetic, electro-magnetic, chemical, or gravitational.

  • The 19th century German scientist Hermann von Helmholtz found that all forms of energy

  • are equivalent, that one form can be transformed into any other. The laws of physics say that

  • in a closed system - such as our universe - energy is conserved. It may be converted,

  • concentrated, or dissipated, but it is never lost.

  • James Prescott Joule built an apparatus that demonstrated this principle. It had a weight

  • that descended into water and caused a paddle to rotate. He showed that the gravitational

  • energy lost by the weight is equivalent to heat gained by the water from friction with

  • the paddle.

  • That led to one of several basic energy yardsticks, called a joule. Its the amount needed to lift

  • an apple weighing 100 grams one meter against the pull of Earth's gravity.

  • In case you were wondering, it takes about one hundred joules to send a tweet, so tweeted

  • a tech from Twitter.

  • The metabolism of an average sized person, going about their day, generates about 100

  • joules a second, or 100 watts, the equivalent of a 100-watt light bulb. In vigorous exercise,

  • the power output of the body goes up by a factor of ten, one order of magnitude, to

  • around a thousand joules per second, or a thousand watts.

  • In a series of leaps, by additional factors of ten, we can explore the full energy spectrum

  • of the universe. So far, the coldest place observed in nature is the Boomerang Nebula.

  • Here, a dying star ejected its outer layers into space at 600,000 kilometers per hour.

  • As the expanding clouds of gas became more diffuse, they cooled so dramatically that

  • their molecules fell to just one degree above Absolute Zero, one degree above the total

  • absence of heat. That is around a billion trillionths of a joule, give or take.

  • That makes the signal sent by the Galileo spacecraft, as it flew around Jupiter, seem

  • positively hot. By the time it reached Earth, its radio signal was down to 10 billion billionths

  • of a watt. Now jump all the way to 150 billionths of a watt.

  • That is the amount of power entering the human eye from a pair of 50-watt car headlamps a

  • kilometer away. Moving up a full seven powers of ten, moonlight striking a human face adds

  • up to three hundred thousandths of a watt. That is roughly equivalent to a crickets chirp.

  • From there, it's a mere five powers of ten to the low wattage world of everyday human

  • technologies.

  • Put ten 100-watt bulbs together. At 1000 joules per second, 1000 watts, that roughly equals

  • the energy of sunlight striking a square meter of Earth's surface at noon on a clear day.

  • Gather 200 bulbs. 20,000 watts is the energy output of an automobile. A diesel locomotive:

  • 5 million watts. An advanced jet fighter: 75 million watts. An aircraft carrier: almost

  • two hundred million watts.

  • The most powerful human technologies today function in the range of a billion to 10 billion

  • watts, including large hydro-electric or nuclear power plants. At the upper end of human technologies,

  • was the awesome first stage of a Saturn V rocket. In five separate engines, it consumed

  • 15 tons of fuel per second to generate 190 billion watts of power.

  • How much power can humanity marshal? And how much do we need?

  • Long before the launch of the space age, visionaries began to imagine what it would take to advance

  • into the community of galactic civilizations. In the 1960s, the Soviet scientist, Nicolai

  • Kardashev, speculated that a Level 1 civilization would acquire the technology needed to harness

  • all the power available on a planet like Earth.

  • According to one calculation, we are .16% of the way there. This is based on British

  • Petroleum's estimate of total world oil consumption, some 11 billion tons in 2007. Humans today

  • generate about two and a half trillion watts of electrical power.

  • How does that stack up to the power generated by planet Earth? Deep inside our planet, the

  • radioactive decay of elements such as uranium and thorium generates 44 trillion watts of

  • power. As this heat rises to the surface, it drives the movement of Earths crustal plates,

  • and powers volcanoes.

  • Remarkably, that is just a fraction of the energy released by a large hurricane in the

  • form of rain. At the storms peak, it can rise to 600 trillion watts. A hurricane draws upon

  • solar heat collected in tropical oceans in the summer.

  • You have to jump another power of ten to reach the estimated total heat flowing through Earths

  • atmosphere and oceans from the equator to the poles, and another two to get the power

  • received by the Earth from the sun, at 174 quadrillion watts.

  • Believe it or not, there's one human technology that has exceeded this level. The AN602 hydrogen

  • bomb was detonated by the Soviet Union on October 30, 1961. It unleashed some 1400 times

  • the combined power of the Nagasaki and Hiroshima bombs.

  • With a blast yield of up to 57 million tons of TNT, it generated 5.3 trillion trillion

  • watts, if only for a tiny fraction of a second. That's 5.3 Yottawatts, a term that will come

  • in handy as we now begin to ascend the power scales of the universe.

  • To Nikolai Kardashev, a Level 2 civilization would achieve a constant energy output 80

  • times higher than the Russian superbomb. That is equivalent to the total luminosity of our

  • sun, a medium-sized star that emits 375 yottawatts.

  • However, in the grand scheme of things, our sun is but a cold spark in a hot universe.

  • Look up into Southern skies and you'll see the Large Magellanic Cloud, a satellite galaxy

  • of our Milky Way. Deep within is the brightest star yet discovered. R136a1 is 10 million

  • times brighter than the sun.

  • Now if that star happened to go supernova, at its peak, it would blast out photons with

  • a luminosity of around 500 billion yottawatts. To advance to a level three civilization,

  • you have to marshal the power of an entire galaxy.

  • The Milky Way, with about two hundred billion stars, has an estimated total luminosity of

  • 3 trillion yottawatts, a three followed by 36 zeros. The author Isaac Asimov imagined

  • a galaxy-scale civilization in his Foundation series. Galaxia, he called it, is a super-organism

  • that surpasses time and space to draw upon all the matter and energy in a galaxy.

  • But who is to say that is the upper limit for civilizations? To boldly go beyond Level

  • 3, a civilization would need to marshal the power of a quasar. A quasar is about a thousand

  • times brighter than our galaxy.

  • Here is where cosmic power production enters a whole new realm, based on the physics of

  • extreme gravity.

  • It was Isaac Newton who first defined gravity as the force that pulls the apple down, and

  • holds the earth in orbit around the sun. Albert Einstein redefined it in his famous General

  • Theory of Relativity. Gravity isn not simply the attraction of objects like stars and planets,

  • he said, but a distortion of space and time, what he called space-time.

  • If space-time is like a fabric, he said, gravity is the warping of this fabric by a massive

  • object like a star. A planet orbits a star when it is caught in this warped space, like

  • a ball spinning around a roulette wheel. Some scientists began to wonder if matter became

  • dense enough, could it warp space to such an extreme that nothing could escape its gravity,

  • not even light?

  • With so much power being emitted from such a small area, scientists suspected that quasars

  • were actually being powered by black holes. How a totally dark object can do this has

  • been narrowed by decades of observations and theory.

  • If a black hole spins, it can turn into a violent, cosmic tornado. Gas and stars begin

  • to flow in along a rapidly rotating disk. The spinning motion of this so-called "accretion

  • disk" generates magnetic fields that twist up and around.

  • These fields can channel some of the inflowing matter out into a pair of high-energy beams,

  • or jets. Gas and dust nearby catch the brunt of this energy, growing hot and bright enough

  • to be seen billions of light years away.

  • Amazingly, the power of a black hole can rise to even greater extremes at the moment of

  • its birth. As a giant star ages, heavy elements like iron gradually build up in its core.

  • As its gravity grows more intense, the star begins to shrink, until it reaches a critical

  • threshold. Its core literally collapses in on itself.

  • That causes the star to explode, in a supernova. And now, in death, the star can unleash gravitys

  • true fury.

  • In the violence of the star's death, gravity can cause its massive core to collapse to

  • a point, forming a black hole.

  • In some rare cases, the new-born monster powers a jet that accelerates to within a tiny fraction

  • of the speed of light. For a few minutes, these so-called gamma ray bursts are known

  • to be the brightest events since the big bang, three orders of magnitude above a quasar at

  • a billion billion yottawatts, a ten with 42 zeros.

  • Remarkably, they are still not the most powerful events known. Albert Einstein's equations

  • contained an astonishing prediction, that when massive bodies accelerate or whip around

  • each other, they can stir up the normally smooth fabric of space-time.

  • They produce a series of waves that move outward like ripples on a pond. Scientists are now

  • hoping to detect these gravitational waves, and verify Einsteins prediction, using precision

  • lasers and some of the most perfect large-scale vacuums ever created.

  • At the Laser Interferometry Gravitational Wave Observatory, known as LIGO, they are

  • hoping to record the collision of ultra-dense remnants of dead stars known as neutron stars

  • and of black holes.

  • According to computer simulations, as two black holes spiral into a fateful embrace,

  • the energy carried by each gravity wave rises five orders of magnitude above a gamma ray

  • burst to a hundred billion trillion times the power of our sun.

  • Does the collision of black holes define the known power limits of our universe? Perhaps

  • not.

  • As turbulent as the environment of a black hole might be, its true power may well lie

  • deep in its core. A black holes mass is enshrouded within a dark sphere called the event horizon.

  • Since the 1920s, scientists have described the mathematics of the event horizon as the

  • equivalent of a waterfall. It's the point of no return, beyond which water falls freely

  • into the gorge.

  • At the event horizon of a black hole, space itself falls freely in at the speed of light.

  • If the black hole is spinning, then the flow spirals down and around an inner horizon that

  • envelops the singularity. That's the central region where space-time becomes infinitely

  • warped.

  • Any matter that rides this river of space whips around the inner horizon so fast that

  • centrifugal force tends to fling it back out. As that happens, it collides with matter that's

  • streaming in, whipping up a ferocious cosmic storm.

  • The energy of the colliding streams feeds upon itself, rising to what may well be a

  • limit imposed by nature. It dissipates only as it falls into the singularity and disappears.

  • Fortunately, for us, gravity walls off such energy extremes behind the event horizon where

  • they cannot affect the rest of the universe.

  • And so here we sit. Our world is nestled within a vast stream of cosmic energy, somewhere

  • between the spin of an electron and the maelstrom of a black hole.

  • There's no telling whether a future Earth civilization will be able harness enough energy

  • to advance into the cosmos.

  • For now, as we tap into the tiny morsels of power at our disposal, we venture a closer

  • look at a universe blazing with activity. We are its product, and its star struck admirer.

All across the immense reaches of