LIGO is funded by the American National Science Foundation; LIGO's mission is to measure gravitational waves.
W and Z bosons are carriers of the weak nuclear interaction. On the other hand, the gluon is the carrier of strong nuclear interaction to bind particles together to form an atomic nucleus. Nonetheless, a so-called graviton that would be the carrier of gravity hasn't been observed! As of 2014, Zvi Bern concluded that a graviton is simply two gluons bound together; he, further, extrapolated that gravity is another manifestation of the strong nuclear force.
In twistor space, "points are lines, and lines are points." Sean Carroll explain that quantum entanglement means that if one electron is spinning clockwise, then the other entangled electron is also spinning clockwise. The Almheiri-Marolf-Polchinski-Sully paradox states that there is a wall of fire at the event horizon (border) of a black hole. A supermassive black hole exists at the center of the Milky Way galaxy.
Thanks for watching. Follow for more videos.
#cosmosspacescience
#throughthewormhole
#season5
#episode7
#cosmology
#astronomy
#spacetime
#spacescience
#space
#nasa
#morganfreeman
#spacedocumentary
#gravity
#illusion
W and Z bosons are carriers of the weak nuclear interaction. On the other hand, the gluon is the carrier of strong nuclear interaction to bind particles together to form an atomic nucleus. Nonetheless, a so-called graviton that would be the carrier of gravity hasn't been observed! As of 2014, Zvi Bern concluded that a graviton is simply two gluons bound together; he, further, extrapolated that gravity is another manifestation of the strong nuclear force.
In twistor space, "points are lines, and lines are points." Sean Carroll explain that quantum entanglement means that if one electron is spinning clockwise, then the other entangled electron is also spinning clockwise. The Almheiri-Marolf-Polchinski-Sully paradox states that there is a wall of fire at the event horizon (border) of a black hole. A supermassive black hole exists at the center of the Milky Way galaxy.
Thanks for watching. Follow for more videos.
#cosmosspacescience
#throughthewormhole
#season5
#episode7
#cosmology
#astronomy
#spacetime
#spacescience
#space
#nasa
#morganfreeman
#spacedocumentary
#gravity
#illusion
Category
ЁЯУЪ
LearningTranscript
00:00We feel it every moment of our lives.
00:05But for physicists, it is the oldest unsolved mystery of the cosmos.
00:14Why does gravity make everything a track?
00:22Cutting-edge theory is closing in on unexpected answers.
00:27Could gravity be another force in disguise?
00:33A shadow of a holographic reality?
00:36Or a rippling mirage?
00:40Do we, Earth, the sun, and the stars, really have weight?
00:47Or is gravity an illusion?
00:51Space. Time. Life itself.
00:59The secrets of the cosmos lie through the wormhole.
01:05The gravitational pull of the sun keeps Earth from flying off into space.
01:25Earth's gravity keeps us firmly planted on the ground.
01:29This all seems real enough.
01:33But scientists are peering deep into the fabric of the universe
01:37and are discovering that gravity may not be what it seems to be.
01:47Can something feel real but not actually be real?
01:53There were some days growing up when there just wasn't anything to do.
02:02So, we would play simple games like target practice with rocks.
02:10Gravity always worked.
02:12No matter what I dropped, I always expected it to fall.
02:24Physicists have their own expectations about gravity.
02:27They believe it to be a fundamental force,
02:30an intrinsic cog in the machinery of the universe.
02:34But experimentalist Nergis Malvalvala isn't taking anything for granted.
02:42So, a fundamental force, like gravity,
02:45that describes how massive objects interact
02:49should be true anywhere you look in the universe.
02:53Isaac Newton showed that every object with mass
02:57attracts every other object with mass.
03:00The greater the mass and the closer they are,
03:03the greater the gravitational attraction.
03:05Over 200 years later,
03:08Albert Einstein explained why this happens.
03:11Space and time are interwoven into a fabric called space-time.
03:19Einstein believed that space-time could bend.
03:23This distortion is what we experience as gravity.
03:28And that's how he understood that objects with mass
03:32attract to each other.
03:33They follow the curvature of space-time.
03:35So, Einstein's picture of gravity was
03:38that mass tells space-time how to curve,
03:41and then the curvature of space-time tells mass how to move.
03:45Einstein also predicted that when all objects with mass move,
03:50they trigger tiny gravitational ripples in the fabric of space-time.
03:54Gravitational waves should permeate the heavens above us.
03:59Nergus believes we should be able to detect those waves,
04:03if they are big enough.
04:05So, if I drop an apple in the middle of a pond,
04:11and I try to detect the ripple at the shore,
04:15it's not going to make it because it's too small of a wave.
04:19Luckily for Nergus,
04:21bodies much more massive than apples cause a stir in the heavens.
04:34Awesome! Whoa!
04:36Around the cosmos,
04:40intense gravitational events like the collision of galaxies
04:45or the explosions of giant stars
04:51should be sending massive volleys of gravitational waves towards Earth.
04:57Nergus has created a way to detect them
05:01with the help of collaborators like Mike Landry.
05:04Nergus and Mike are part of the largest experiment
05:08ever built by the National Science Foundation.
05:11It is known as the Laser Interferometer Gravitational Wave Observatory,
05:16or LIGO.
05:18In this behemoth,
05:20laser beams fire down two vacuum tubes arranged in an L shape.
05:25Each arm is four kilometers long.
05:29The laser beams can measure the length of each arm
05:33with an accuracy of better than one millionth of the width of an atom.
05:38If a gravitational wave from any intense cosmic event
05:41up to 500 trillion trillion miles away
05:44passes through the Earth,
05:46the space inside the tubes will ripple,
05:49the lasers will detect the change,
05:51and the alarm bells will ring.
05:56After almost a decade of listening to the heavens,
06:01LIGO picked up the sound of crickets.
06:06We didn't observe a gravitational wave
06:11in the initial science runs of LIGO.
06:14Nergus, Mike, and the thousands of scientists at LIGO
06:17have one more shot.
06:19They're working on advanced upgrades
06:21that will increase LIGO's sensitivity tenfold.
06:25But there's no guarantee they'll ever get a signal.
06:28Well, if we don't detect gravitational waves with advanced LIGO,
06:32first I'll cry.
06:34But then I think it's actually very exciting either way.
06:37If we don't see gravitational waves,
06:39then it's going to start off a different kind of revolution
06:42where there'll be a lot of head scratching
06:44about what is it about nature we don't understand.
06:49Nergus is hopeful.
06:51In fact, in March of 2014,
06:54a group of astronomers claimed to have detected gravitational waves
06:58produced by the Big Bang.
07:01But some scientists take the deafening silence at LIGO
07:04as evidence that gravity may not be a fundamental force.
07:10When an apple falls to the Earth,
07:12something else could be pulling it down.
07:15Physicists believe that everything in the universe,
07:18even the pulse of energy that we call force,
07:21force is made from particles.
07:25Gravity should be no exception.
07:38Zvi Bern is a particle physicist
07:42with a very active imagination.
07:46He's imagining what a game of mini-golf would look like
07:50if the balls were shrunk to the size of subatomic particles
07:53and ruled by the laws of quantum mechanics.
07:56Quantum mechanics is full of the strangest things you can imagine.
08:03The concept of a particle being at one point,
08:07that becomes a very fuzzy concept in quantum mechanics.
08:10Subatomic particles are unlike anything you can see with your naked eye.
08:15They become fuzzy when no one looks at them.
08:19Sometimes they can appear out of nowhere
08:22and then suddenly vanish.
08:26Some of these appearing and disappearing particles
08:29transmit the fundamental forces of nature.
08:32Electromagnetism, the strong force, the weak force,
08:37and supposedly gravity.
08:42I have here a golf ball.
08:44The golf ball represents a photon.
08:46The photon is the carrier of the electromagnetic force.
08:50The electromagnetic force attracts or repels anything with an electric charge.
08:57The next golf balls, these represent the W and the Z boson.
09:01The W and the Z boson, these are the carriers of the weak nuclear interaction.
09:05The weak force causes the nucleus of a radioactive atom to break apart.
09:10The next golf ball, it represents the gluon.
09:13The gluon is the carrier of the strong nuclear interaction.
09:16The strong force binds particles together to form an atomic nucleus.
09:23Gravity should also be carried by a particle,
09:27but no one has ever observed this so-called graviton.
09:32In fact, when physicists try to calculate how the theoretical graviton might work,
09:38they quickly get lost in impossible math.
09:41Gravity, unfortunately, is one of our most complicated theories in the way it interacts.
09:46And what happens is, as you do these calculations,
09:49very quickly you start encountering expressions
09:51with no computer in the world or all the world's computer.
09:55They couldn't possibly do those calculations.
09:58But Zvi has a trick up his sleeve to calculate whether or not the graviton exists.
10:05Quantum theory, like many golf, is a game of probability.
10:10Trying to hit a hole in one is difficult.
10:14There are so many ways the ball could go.
10:18But break up the hole into smaller pieces, and things are much more manageable.
10:30Together with some colleagues, we developed an idea that we call the Unitarity Method.
10:35And the basic idea of that is you take the bigger problem of these interactions, these complications,
10:41and then you chop it into smaller pieces.
10:44And then, by solving the smaller problems and assembling it,
10:47you can do a lot better than if you were just trying to solve the whole problem at once.
10:51When Zvi and his colleagues applied their Unitarity Method to gravitons,
10:57an unexpected result came back.
10:59What we discovered about the graviton is that, in a very precise way,
11:03it can be interpreted as two copies of gluons.
11:06Which binds the nuclei of atoms together through the strong force.
11:11But Zvi and his colleagues believed gluons could also be responsible for gravity.
11:17The graviton could actually be a pair of gluons.
11:21Everything became instantly clear.
11:23It's like a moment of insight, the eureka moment.
11:25This is our eureka moment, where we really knew that we understood it.
11:30And the fact that it came out that simple really was the great surprise.
11:35We always had suspicions that something like this was true.
11:38But that it works as simply as it did, that was really the big surprise for us.
11:43Zvi's work could mean that when an apple falls,
11:47the gravity that pulls it down is just another manifestation of the strong force.
11:52The same force that holds the nucleus of tiny atoms together,
11:57could also be responsible for holding colossal celestial bodies in orbit.
12:02If so, the universe is awash in gluons, working together as gravitons.
12:10Every time a pair of gluons is exchanged between massive objects,
12:15the objects move a little bit closer together.
12:19Scientists are discovering that our assumptions about gravity
12:24may be almost completely wrong.
12:29A whole new side of gravity could be waiting to be discovered.
12:32In fact, we may soon discover objects that fall up.
12:41Most physicists believe that gravity is a force that only attracts.
12:46But cosmologists have recently discovered that galaxies appear to be pushing each other apart
12:53at an ever-increasing rate.
12:56Perhaps it's time to reconsider what we think we know about gravity.
13:03Dragon Hadjukovic is a physicist at the European Center for Nuclear Research,
13:16or CERN, in Geneva, Switzerland.
13:19But he does his best work when visiting his home country of Montenegro.
13:24Dragon is using his time at home to catch up with old friends
13:28and work out a new theory of gravity.
13:31One that involves the most dangerous material in the universe.
13:35Anti-matter.
13:37I have a red apple, which is made from matter,
13:43and the blue one, which is made from anti-matter.
13:49Fortunately, it's not a true anti-matter,
13:52but if we assume that it is, look what will happen.
13:58Fortunately for us, there isn't enough anti-matter in the vicinity of Earth to ever blow it up.
14:10But Dragon thinks that if there were ever such a thing as an anti-matter apple,
14:15it would have an unusual gravitational property.
14:19It is quite possible that anti-matter falls up.
14:24Dragon suspects that anti-matter and matter repel each other,
14:29and that hidden pockets of anti-matter could be responsible for pushing the universe apart.
14:35Physicists use the term quantum vacuum to describe the space that fills every corner of the cosmos.
14:43Don't let the name fool you.
14:45It's bubbling with microscopic activity.
14:48At every point in the quantum vacuum,
14:51tiny, innocuous pairs of matter and anti-matter particles are popping in and out of existence.
14:58They exist for a split second before annihilating each other.
15:03There are billions of billions of billions of billions and let's stop.
15:09We can continue of pairs in a metric cube of the quantum vacuum.
15:14So they must play a role in theory of gravity.
15:20Think of the quantum vacuum like a typical Montenegrin town.
15:25Every particle of matter always dances with a partner.
15:31When a pair of tiny dancers pops into existence,
15:35the gravity of the matter is cancelled out by the anti-gravity of the anti-matter.
15:41So normally, no matter how many pairs of particles and anti-particles are created,
15:47the resulting gravitational effect is zero.
15:51But the quantum vacuum doesn't always exist in a vacuum.
15:54The universe is filled, after all, with giant islands of matter called galaxies.
16:01If you put matter inside, it spools the symmetry and you have gravitational effects.
16:11At the end of a Montenegrin folk dance, male dancers are drawn into the center to form a massive structure.
16:17The female dancers are pushed outwards.
16:23In Dragon's theory, tiny particles of matter and anti-matter in the quantum vacuum follow the same steps.
16:33Galaxies are made of matter.
16:39They pull in the matter in the quantum vacuum and push its anti-matter away.
16:45So there's slightly less matter and slightly more anti-matter in the space between galaxies.
16:52So the quantum vacuum becomes gravitationally repulsive and galaxies are pushed apart.
17:01Physicists can see this galactic drift happening.
17:04They are not sure where the energy that is causing it comes from.
17:08So they call it dark energy.
17:12But Dragon thinks dark energy is gravity's hidden dance partner.
17:17Mainstream physicists try to explain it by the existence of dark energy.
17:22But once again, no one knows what's dark energy.
17:25Now, what's the sampler solution?
17:28To invoke dark energy or to assume gravitational repulsion between matter and anti-matter?
17:40Dragon's theory is controversial.
17:44But we may soon find out if gravity has a repulsive alter ego.
17:49Back at CERN, Dragon's colleagues are using the Large Hadron Collider to produce anti-hydrogen.
17:58If it falls up, we may finally have an explanation for dark energy.
18:05Or it could be another false step on the road to understanding gravity.
18:11I think that our understanding is incomplete.
18:14If you try to explain astronomical phenomena by our best physics, it's a disaster.
18:23Our gravitational theories are broken.
18:27Neither Einstein's theory nor quantum physics explains all of what we observe.
18:32Is gravity a trick of the mind?
18:35Or perhaps gravity is what's real and reality itself is the illusion.
18:41We used to believe the Earth was flat.
18:47But seafarers proved this was an illusion.
18:52The horizon only looks flat because our planet is so large.
18:56Change your perspective by flying high enough and you can see the curvature of Earth.
19:03If gravity is an illusion, can we find a new perspective on it and see it for what it is?
19:19Princeton University's Hermann Verlinde is soul-searching.
19:22Multiple experiments have shown that Einstein's theory that gravity is the warping of space and time appears to be correct.
19:32But an equally powerful theory, quantum mechanics, says that Einstein's theory cannot explain what gravity is made of.
19:41Einstein told us that if you move through space, you don't notice it.
19:46Because space is empty, it's not made out of anything.
19:50But quantum theory tells you that actually, that there must be a granularity to space.
19:56Just like the sand.
20:05Einstein's theory says that the particle that carries gravitational force, the graviton, must float on the completely smooth surface of empty space.
20:15Like the surface of the sea.
20:18But according to quantum mechanics, space is not smooth at all.
20:23It is made up of little grains, which make for a bumpy ride.
20:28But Hermann is beginning to think both theories may be correct.
20:32Because reality itself may be deceiving us.
20:37Einstein famously got into trouble by thinking that reality should really exist, and they call that an objective reality.
20:49But in physics, we know that the world is not quite what it seems.
20:53Objects that travel at the speed of light, like a photon or a graviton, will see a dramatically different version of reality.
21:02When the ball approaches the speed of light, something very strange happens.
21:07The rest of the world seems to become shorter.
21:10And the faster the ball goes, the shorter the rest of the world becomes, until it becomes flat like a plane.
21:17If you were a graviton, you would be convinced that you were always standing still, and the entire universe was a flat sheet in front of you.
21:31We observe particles in our reality moving in linear paths.
21:36But from a particle's point of view, there may be no such thing as moving at all.
21:42In the late 1960s, mathematician Roger Penrose proposed a new way to see the world.
21:49He said that particles that move at the speed of light, like photons and the theoretical graviton, experience an alternate reality he called twistor space, where points are lines and lines are points.
22:06In twistor space, the paths that the graviton travels become points.
22:11So it's a new set of coordinates for space and for time.
22:16The idea of a hidden reality seemed preposterous 50 years ago.
22:23But a more recent idea in physics suggests Penrose was ahead of his time.
22:29It is a theory physicists call the holographic principle.
22:35The holographic principle is the idea, things that we see in space are actually sort of a reflection of some other reality on holographic screen.
22:52It's as if the actual reality is sitting on the walls of this room.
22:56Herman is marrying these two ideas into twistor holography.
23:03It's a reality-bending theory where Einstein's gravity and quantum mechanics get along just fine.
23:16Einstein's theory requires that the graviton move through smooth space.
23:21But in twistor holography, the path of the graviton's movement is a point.
23:28It doesn't matter whether the graviton is floating on water or sand, because in this reality the graviton stays completely still.
23:36If Herman is correct, gravity is real in an altered reality.
23:43And what we experience as reality could be an illusion constructed from something else.
23:55It's kind of like watching a good TV show.
23:57You might not realize that an invisible group behind the scenes created it.
24:02And cut.
24:04Tell me about reality in life and in physics.
24:08In physics, reality is sometimes not unique and sometimes not objective and sometimes deceptive.
24:17You're sitting here and you're real to me.
24:22But who knows, maybe someone is tricking me.
24:25If gravity is the universe's greatest mirage, then it must be created from something.
24:35A groundbreaking theory now argues that gravity could be another form of pure heat.
24:44The ancient Greeks believed that fire was a fundamental element of the universe.
24:55But thermodynamics, the study of how microscopic objects create macroscopic effects, proved the Greeks incorrect.
25:05Fire is a phenomenon created from the furious motion of hot atoms.
25:11Now a bold new theory is setting the world of physics ablaze.
25:16It suggests that, like fire, gravity is a thermodynamic mirage.
25:31The science community is heralding a recent discovery as one of the greatest revelations of gravitational physics.
25:39And it's all thanks to this man.
25:42No, it's not Herman Verlinde.
25:45It's his identical twin brother, Erik.
25:48Well, as a child, Herman and I discussed a lot about what we found interesting.
25:53When we would read something, we would talk about it, and we shared our excitement in physics.
25:58Erik and Herman lived similar lives in Holland.
26:02They both got their PhDs in physics from Utrecht University and even married two sisters.
26:09But Erik's parallel path would take a dramatic turn when a little chaos showed up at his doorstep.
26:17I was vacationing and I came back from a run and I came into my apartment and then I saw someone had broken in and stolen my car key, my laptop, my passport.
26:34Many things got lost.
26:36Physicists use the term entropy to describe the amount of chaos in a system.
26:42Entropy in the universe is always increasing.
26:47In physics and in life, things naturally go from order to disorder.
26:52Turning entropy into order requires energy, just like when Erik had to expand energy to restore order to his house.
27:00While dealing with the unexpected chaos, Erik was hit with a flash of inspiration.
27:07There is a deep connection between entropy and gravity.
27:13Imagine traveling to the surface of a neutron star where the intense gravity would make you weigh 140 trillion times more than you do on Earth.
27:25It's enough to significantly raise the entropy of the atoms inside you.
27:32As objects fall toward a massive body, they experience an ever stronger gravitational pull.
27:43And so, their entropy also goes up.
27:46What I realized is that what causes gravity is that the apple when it's here has less entropy than when it's down on the floor.
27:56And nature tries to increase entropy or tends to increase entropy.
28:00This is why if I let go of the apple, it will try to get as much entropy as possible and this is why it's falling.
28:08Eric believes that objects with mass fill the force of gravity because the universe is increasing the amount of disorder or entropy deep inside them.
28:26A force that is created from entropy is nothing new to physicists who understand thermodynamics.
28:33In fact, the entropy inside a hot air balloon will lift you up into the sky.
28:40So, a hot air balloon contains molecules. Those molecules are moving.
28:45They want to increase the entropy and this they can do by getting more space inside the balloon.
28:51And if the balloon expands, it actually can do so by moving up.
28:55The hot air inside the balloon tries to increase its entropy by pushing outward and upward.
29:04This results in an emergent force called buoyancy.
29:11Buoyancy is not a true force. It's created from the entropy of air molecules.
29:18Eric thinks that gravity is also created from the entropy of something else.
29:23Perhaps from disorder in the very fabric of space and time.
29:30Eric doesn't yet know what it is created from.
29:34But he feels sure gravity cannot be a fundamental force of the universe.
29:39From the fact that I can derive gravity from changes in entropy,
29:44it basically means we have to think about gravity in a different way.
29:47Instead of assuming it as a fundamental force,
29:50we can now view it as something that can be emergent.
29:58We might find out the truth about gravity if we could feel it more intensely.
30:03This is impossible on Earth where gravity is weak.
30:06But there is a place in the universe where gravity reigns supreme.
30:11inside a black hole.
30:14Here it may completely incinerate matter in a wall of gravitational fire.
30:26In unusual situations, you don't always get what you expect.
30:38But sometimes, unusual situations lead to new insights.
30:44To find the truth about gravity, physicists are studying it in a place where they expect it to...
30:50That's very strangely.
31:01Physicist Sean Carroll has a lot on his mind.
31:06Gravity is the hardest problem in physics, and he's tackling it head-on.
31:11The fact that gravity is hard was a surprise to everybody.
31:15We're really going to need a breakthrough, a different way of thinking about gravity.
31:18Physicists know where to look for new insights about gravity.
31:25Inside, a black hole.
31:28These cosmic monsters form when stars collapse.
31:33The entire mass of the star is compressed into a single point,
31:37where gravity reaches its theoretical maximum.
31:41Surrounding every black hole is an invisible, intangible shell known as the event horizon.
31:50The point beyond which not even light can escape the black hole's gravity.
31:55No one knows what actually exists on the other side of this boundary.
32:00Gravitational field in that region of space is so strong that it's a one-way ticket.
32:04You go in, and you can explore around inside, and you can never come back out.
32:12Theoretical physicists like Sean turn to their imaginations for answers.
32:17Suppose you're astronaut Alice, a daring cosmic explorer willing to take the plunge into a black hole.
32:24Our current best theory of gravity says that you wouldn't even notice there was an event horizon.
32:33There are certain cherished principles that we like to hold on to.
32:36One of them is simply called no drama.
32:39You could pass right through the event horizon, and it wouldn't look any different than any other place in the universe.
32:44So, there's no drama when you're near the black hole.
32:49Physicists have long believed that when you cross the event horizon, nothing dramatic happens.
32:56Until you're deep inside the black hole, and the rising gravitational intensity turns you into human spaghetti.
33:07But scientists are learning that this time-honored story might not hold up.
33:14The laws of gravity may break down at the event horizon.
33:19Inside, gravity could be something entirely different, or not exist at all.
33:26Physicists started to notice contradictions after calculating how particles in and around black holes connect to each other through a process called entanglement.
33:39Entanglement says I can have two electrons, and I don't know what either one of them is doing.
33:44But if they're entangled, and I measure one, and I see it spinning clockwise, then I know instantly the other one is also spinning clockwise.
33:52Another cherished principle of physics states that particles are strictly monogamous.
33:57They can only entangle with one partner at a time, no matter what.
34:01But our understanding of the physics of black holes seemed to imply that particles at the event horizon needed to have more than one entangled partner.
34:12This was a scenario no physicist was willing to entertain.
34:16So this is what we call the Omeri-Morolf-Polchinski-Sully paradox, after the four Santa Barbara physicists who proposed it.
34:30The four physicists proposed a dramatic solution to the paradox.
34:37It was time to let go of the cherished principle of no drama at the event horizon.
34:43In fact, something very dramatic happens.
34:46If you went to the event horizon of a black hole and visited there, you'd be incinerated by a wall of fire.
34:59Black holes may be surrounded by a wall of fire so powerful that it either incinerates any particle going into it,
35:09or perhaps incinerates the very fabric of space and time.
35:13If there's a firewall, that means there's somehow there's a boundary, there's an edge.
35:18And when you hit that region, we're not sure what happens.
35:21It seems like maybe what happens is that whatever is there is not space and time anymore.
35:27It's still quantum mechanics, but it's not good old gravity and space-time as Einstein would have understood it.
35:33Past the black hole firewall, gravity could take on an entirely new form.
35:38If we could find out exactly what that form is, we may learn the true nature of gravity everywhere else in the cosmos.
35:49Seeing the event horizon of a black hole was once thought to be impossible.
35:54But this astronomer thinks he has a shot at it.
35:58He's building the largest telescope the world has ever seen.
36:0826,000 light years away, there's a place where we could learn the true nature of gravity.
36:15It's the supermassive black hole at the center of our galaxy.
36:20Astronomers think this hole in space is not much bigger than our sun.
36:24Seeing something that size so far away would take a telescope the size of our planet.
36:33So, why not build one?
36:38Astronomer Shep Doleman's career was launched when he answered the call to adventure and landed...
36:47here.
36:49What excited me about this particular brand of radio astronomy was that you got to travel the world.
36:57I said, well, that's for me.
36:58I definitely want to go out into the field and do that.
37:01And then when I got here, they said, well, largely that work's been done.
37:04Shep does most of his work trapped in his office, where he often escapes by daydreaming...
37:10about being the first astronomer to observe a black hole.
37:17It's one of the hardest problems in his field, because astronomers can only observe objects that radiate light.
37:25When you ask yourself what a black hole looks like, you really have to begin with, why do we see black holes at all?
37:31By definition, they should be invisible.
37:36When light enters a black hole, it's gone forever.
37:41But not all of the light around the black hole gets sucked in.
37:45Some of it bends around the event horizon, creating a shadow image of the black hole.
37:50That image could reveal how gravity behaves at the event horizon.
37:57But by the time the light reaches us, the signal is so diluted that Shep would need a telescope thousands of miles across to pick it up.
38:08So, he set out to build one.
38:11Shep is traveling to exotic locations around the world, coordinating a massive international collaboration.
38:23In the spring of 2015, nearly all of the world's high-precision telescopes will point towards the center of our galaxy.
38:33So, at the center of our galaxy is an extraordinary object.
38:37It's a supermassive black hole.
38:38And because it is so massive, and because it's relatively close to us, we have a shot, we have a chance to resolve it.
38:48To resolve an image of this black hole, Shep's team devised a method that turns a collection of individual telescopes into one virtual telescope the size of our planet.
39:03Well, right now, I'm in the center of the Earth, represented by this ball field.
39:08And we're going to see water flying out of a nozzle.
39:11And you can think of that as light coming from a cosmic object, say, a black hole.
39:15And a single telescope can only capture a small amount of that data.
39:19We're going to put telescopes around the entire ball field.
39:21And they're going to capture all the water flow and sample very comprehensively all the data that we need to make an image of the object.
39:30When matter falls into a supermassive black hole, it spews radiation out into space.
39:48Shep is trying to reconstruct the shape of the light as it leaves its source.
39:52It's just like water leaving a nozzle.
39:55The further it travels, the more the spray spreads out.
40:01But if enough collectors are spread out over a wide enough area, the amount caught in each one would allow you to reconstruct the shape of the nozzle.
40:09The nozzle of the hose is spraying information out.
40:18With a single telescope or a single cup, you can only record or capture part of the information coming from the nozzle.
40:26But with many cups spread out all over the field, you sample the full information field from the object you're looking at, in this case the nozzle.
40:34And you can recreate and understand what was happening when the water left that very small volume.
40:41Shep's Planet Science Virtual Telescope should have enough resolution to determine the gravitational physics at the edge of a black hole.
40:50Gravity is a theory.
40:53It works very well on the Earth.
40:56But we haven't put it to ultimate tests.
40:59We haven't put it to the test where gravity is dominant at the edge of a black hole.
41:03So, this is one place where gravity could conceivably break down.
41:07And it's very important to test these theories, because it's the only way we understand the nature of reality.
41:13Really the only way we understand the fundamental basis of what we believe about the universe.
41:23Gravity feels real.
41:25It holds all of us to this little rock we call home.
41:31But gravity may not be what it seems.
41:35If gravity is an illusion,
41:38then it's time to call into question everything we think we know about the cosmos.
41:45Only when we let go of what we feel to be correct,
41:49can we taste the real truth.
41:52clinical Momo
41:56You
41:57You
41:59You
Be the first to comment