Cosmic Journeys: The Most Powerful Objects in the Universe

[00:00:03][music] >> 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.

[00:00:36]How does energy stitch the cosmos together?

[00:00:42]And how do we fit within [music] it?

[00:00:47]We now climb the power scales of the universe, >> [music] >> from atoms nearly frozen to stillness, to Earth's largest explosions.

[00:01:02]>> [music] >> From stars colliding, exploding, >> [music] >> to distant realms so strange and violent, they challenge our imaginations.

[00:01:26]Where will we find the most powerful objects in the universe?

[00:01:31]>> [music] >> Today, energy [music] is very much on our minds as we search for ways to power our civilization and serve the needs of our citizens.

[00:02:02]But, what is energy?

[00:02:04]Where does it come from?

[00:02:07]And where do we stand within [music] the great power streams that shape time and space?

[00:02:19]Energy comes from a Greek word for activity or working.

[00:02:27]In physics, it's simply the property of the state of anything in our universe that allows it to do work.

[00:02:36]Whether it's thermal, kinetic, electromagnetic, >> [music] >> chemical, or gravitational.

[00:03:01]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.

[00:03:17]The laws of physics say that in a closed system, such as our universe, energy is conserved.

[00:03:27]It may be converted, concentrated, or dissipated, but it's never lost.

[00:03:38]James Prescott Joule built an apparatus that demonstrated this [music] principle.

[00:03:44]It had a weight that descended into water and caused a paddle to rotate.

[00:03:50]He showed that the gravitational energy lost by the weight is equivalent to heat gained by the water from friction with the paddle.

[00:04:01]That led to one of several basic energy yardsticks called a joule.

[00:04:06]It's the amount needed to lift an apple weighing 100 g 1 m against the pull of Earth's gravity.

[00:04:15]In case you were wondering, it takes about 100 joules to send a tweet, so tweeted [music] a tech from Twitter.

[00:04:25]The metabolism of an average-sized person going about their day generates about 100 joules a second, or 100 W, the equivalent of a 100 W light bulb.

[00:04:41]In vigorous exercise, the power output of the body [music] goes up by a factor of 10, one order of magnitude, to around 1,000 joules per second, or 1,000 W.

[00:04:59]In a series of leaps by additional [music] factors of 10, we can explore the full energy spectrum of the universe.

[00:05:11]So far, [music] the coldest place observed in nature is the Boomerang Nebula.

[00:05:17]Here a [music] dying star ejected its outer layers into space at 600,000 km/h.

[00:05:26]As the expanding [music] clouds of gas became more diffuse, they cooled so dramatically that their molecules fell to just 1° above absolute zero, the total absence of heat.

[00:05:41]That's around [music] a billion trillionths of a joule.

[00:05:45]That makes the signal sent by Galileo spacecraft as it flew around Jupiter seem positively hot.

[00:05:54]By the time it reached Earth, its radio signal was down to 10 billion billions of a watt.

[00:06:04]Now, jump all the way [music] to 150 billionths of a watt.

[00:06:09]That's the amount of power entering the human eye from a pair of 50 watt car headlamps a kilometer away.

[00:06:21]Moving up a full seven powers of 10, moonlight striking a human face adds up to 300,000ths of a watt.

[00:06:31]That's roughly equivalent to a cricket's chirp.

[00:06:36]From there, it's [music] a mere five powers of 10 to the low wattage world of everyday human technologies.

[00:06:45]Put 10 100 watt bulbs together.

[00:06:49]At 1,000 joules per second, 1,000 watts.

[00:06:54]That roughly equals the energy of sunlight striking a square meter of Earth's surface at noon on a clear day.

[00:07:04]Gather 200 bulbs.

[00:07:06]20,000 watts is the energy output of an automobile.

[00:07:14]A diesel locomotive, 5 million watts.

[00:07:20]An advanced jet fighter, 75 million watts.

[00:07:26]An aircraft carrier, almost 200 million watts.

[00:07:34]The most powerful human technologies today function in the range of a billion to 10 billion watts, including large [music] hydroelectric or nuclear power plants.

[00:07:52]At the upper end of human technologies was [music] the awesome first stage of a Saturn V rocket.

[00:08:01]In five separate engines, [music] it consumed 15 tons of fuel per second to generate 190 [music] billion watts of power.

[00:08:15]How much power can humanity marshal?

[00:08:19]And how much do we need?

[00:08:25]Long before the launch of the space age, visionaries [music] began to imagine what it would take to advance into the community of galactic civilizations.

[00:08:38]In the 1960s, the Soviet scientist [music] Nikolai Kardashev speculated that a level one civilization would acquire the technology needed [music] to harness all the power available on a planet like Earth.

[00:08:55]According to one calculation [music] we are 0.16% of the way there.

[00:09:01]This is based on British Petroleum's estimate of total world oil consumption some 11 billion tons in 2007. [music] Humans today generate about 2.5 trillion watts of electrical power.

[00:09:21]How does that stack up to the power generated by planet Earth?

[00:09:29]Deep inside our planet, the radioactive decay of elements such as uranium and thorium generates 44 trillion watts of power.

[00:09:43]As this heat rises to the surface, it drives the movement of Earth's crustal plates and powers volcanoes.

[00:09:53]Remarkably, that's just a fraction of the energy released by a large hurricane in the form of rain.

[00:10:03]At the storm's peak, it can rise to 600 trillion watts.

[00:10:12]A hurricane draws upon solar heat collected in tropical oceans in the summer.

[00:10:21]You have to jump another power of 10 to reach the estimated [music] total heat flowing through Earth's atmosphere and oceans from the equator to the poles.

[00:10:32]And another two to get the power received by the Earth from the Sun.

[00:10:38]At 174 quadrillion [music] watts.

[00:10:45]Believe it or not, there's one human technology that has exceeded this level.

[00:10:53]The AN602 [music] hydrogen bomb was detonated by the Soviet Union on October 30th, 1961. [snorts] It unleashed [music] some 1,400 times the combined power of the Nagasaki and Hiroshima bombs.

[00:11:14]With a blast yield of up to 57 million tons of TNT, it generated 5.3 trillion trillion watts.

[00:11:24]If only for a tiny fraction of a second.

[00:11:28]That's 5.3 yottawatts.

[00:11:33]A term that will come in handy.

[00:11:35]>> as we now begin [music] to ascend power scales of the universe.

[00:11:39]>> off of Discovery, a tribute to the dedication, hard work, and pride >> To Nikolai Kardashev, a level two civilization would achieve a constant energy output 80 times higher than the Russian super bomb.

[00:11:57]That's equivalent to the total luminosity of our sun.

[00:12:01]A medium-sized star that emits 375 yotta watts.

[00:12:10]However, in the grand scheme [music] of things, our sun is but a cold spark in a hot universe.

[00:12:20]Look up into southern [music] skies and you'll see the Large Magellanic Cloud, a satellite galaxy of our Milky Way.

[00:12:30]Deep within is the brightest star yet discovered.

[00:12:37]R136a1 is 10 million times brighter than the sun.

[00:12:46]Now, if that star happened to go supernova, [music] at its peak, it would blast out photons with a luminosity of around 500 billion yotta watts.

[00:13:02]>> [music] >> To advance to a level three civilization, you have to marshal the power of an entire galaxy.

[00:13:11]The Milky Way, with about 200 billion stars, has an estimated total luminosity of 3 trillion yotta watts.

[00:13:22]A three followed by 36 [music] zeros.

[00:13:31]The author Isaac [music] Asimov imagined a galaxy-scale civilization in his Foundation series.

[00:13:40]Galaxia, [music] he called it, is a superorganism that surpasses time and space to draw upon all the matter and energy in a galaxy.

[00:13:54]But who's to say that's [music] the upper limit for civilizations?

[00:14:00]To boldly go beyond level three, a civilization would need to marshal the power of a quasar.

[00:14:11]>> [music] >> A quasar is about a thousand times brighter than our galaxy.

[00:14:19]Here is where cosmic power production enters a whole new realm based on the physics of extreme [music] gravity.

[00:14:30]It was Isaac Newton who first defined gravity as the force that pulls the apple down >> [music] >> and holds the Earth in orbit around the Sun.

[00:14:41]Albert Einstein redefined it in his famous general theory of relativity.

[00:14:50]Gravity isn't simply the attraction of objects like stars and planets, he said, but a distortion of space and time, what he called space-time.

[00:15:04]If space-time is like a fabric, gravity is the warping of this fabric [music] by a massive object like a star.

[00:15:15]A planet orbits a star [music] when it's caught in this warped space like a ball spinning around a roulette wheel.

[00:15:24]Some scientists [music] 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?

[00:15:40]With so much power being emitted from such a small area, scientists suspected that quasars were actually being powered by black holes.

[00:15:52]How a totally dark object can do this has been narrowed by decades of observations and theory.

[00:16:01]If a black hole spins, it can turn into [music] a violent cosmic tornado.

[00:16:07]Gas and stars [music] begin to flow in along a rapidly rotating disk.

[00:16:16]The spinning motion of this so-called accretion disk generates magnetic fields that twist up and around.

[00:16:26]These fields can channel some of the inflowing matter out into a pair of high-energy beams or jets.

[00:16:35]Gas [music] and dust nearby catch the brunt of this energy, growing hot and bright enough to be seen billions of light-years away.

[00:16:47]Amazingly, [music] the power of a black hole can rise to even greater extremes at the moment of its birth.

[00:17:08]As a giant star ages, heavy elements like iron gradually build up in its core.

[00:17:18]As its gravity grows more intense, the star [music] begins to shrink until it reaches a critical threshold.

[00:17:30]Its core literally collapses in on itself.

[00:17:41]That causes the star to explode in a supernova.

[00:17:48]And now in death, the star can unleash gravity's true fury.

[00:17:58]In the violence of the star's death, gravity can cause its massive core to collapse [music] to a point forming a black hole.

[00:18:11]In some [music] rare cases, the newborn monster powers a jet that accelerates [music] to within a tiny fraction of the speed of light.

[00:18:22]>> [music] >> For a few minutes, these so-called gamma-ray bursts are known to be the brightest [music] events since the Big Bang.

[00:18:35]Three [music] orders of magnitude above a quasar at a billion billion yottawatts, a 10 with 42 [music] zeros.

[00:18:50]Remarkably, they are still not the most powerful events known.

[00:18:57]Albert Einstein's equations contained an astonishing [music] prediction.

[00:19:04]That when massive bodies accelerate or whip around each other, they can stir up the normally smooth fabric of space-time.

[00:19:13]They produce a series of waves that move outward like ripples on a pond.

[00:19:26]Scientists are now hoping to detect [music] these gravitational waves and verify Einstein's prediction using precision lasers and some of the most perfect [music] large-scale vacuums ever created.

[00:19:44]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 [music] neutron stars and of black holes.

[00:20:06]According to computer simulations, as two [music] 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.

[00:20:34]Does the collision of black holes define the known power limits of our universe?

[00:20:40]Perhaps not.

[00:20:42]>> [music] >> As turbulent as the environment of a black hole might be, its true power may well [music] lie deep in its core.

[00:20:55]A black hole's mass is enshrouded within a dark sphere called the event [music] horizon.

[00:21:02]Since the 1920s, scientists have described the mathematics of the [music] event horizon as the equivalent of a waterfall.

[00:21:14]It's the point of no return, beyond [music] which water falls freely into the gorge.

[00:21:23]At the event horizon of [music] a black hole, space itself falls freely in at the speed of light. [music] >> [music] >> If the black hole is spinning, then the flow spirals down and around an inner horizon that envelops the singularity.

[00:21:49]That's the central region where space-time becomes infinitely warped.

[00:21:58]Any matter that rides this river of space whips around the inner horizon so fast that centrifugal force tends to fling it back out.

[00:22:14]As that happens, it collides with matter that's streaming in, whipping up a ferocious [music] cosmic storm.

[00:22:29]The energy of the colliding stream [music] feeds upon itself, rising to what may well be a limit imposed by nature.

[00:22:40]It dissipates only as it falls into the singularity >> [music] >> and disappears.

[00:22:52]Fortunately for us, gravity walls off such energy extremes behind the event horizon, where they cannot affect the rest of the universe.

[00:23:10]And so, here we sit.

[00:23:12]Our world is nestled within a vast stream of cosmic energy.

[00:23:18]Somewhere between [music] the spin of an electron and the maelstrom of a black hole.

[00:23:28]There's no telling whether a future Earth civilization will be able to harness enough energy to advance into the cosmos.

[00:23:42]For now, as we tap [music] into the tiny morsels of power at our disposal, we venture a closer look at a universe blazing [music] with activity.

[00:23:57]>> [music] >> We are its product and its starstruck admirer.

[00:24:08]>> [music] [music] [music] [music] >> Mhm.