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. [music playing] They are the freaks of the
cosmos, pulsars and quasars, so strange their very
existence seems impossible. They must be titanic,
absolute monsters. NARRATOR: What makes them shine
with the light of a billion Suns, rotate faster than
the blink of an eye, or bang out cosmic rhythms with
the drummer from the Grateful Dead? Once all of these things
started to come my way, I realized that, you know,
the universe was singing. NARRATOR: But it's a tune
bizarre beyond imagination with pulsars and
quasars, the superstars of an astronomical
sideshow found only in the strangest
sectors of the universe. [theme music] [music playing] NARRATOR: In 1967,
scientists on planet Earth made a startling discovery. Something, someone was sending
us signals through space. Were aliens trying
to send us a message? When pulsars were first
discovered, they blew us away. Something in the night sky
was turning on and off. How could something
in nature do that? And so we actually called
them LGM objects, that stood for Little Green Men. NARRATOR: Astronomers in
England detected the signals using a primitive radio
telescope, a massive array of poles and wires stretched
out over 4 acres of land. The first of the signals was
not just an isolated peak in the radio noise. It was a regular blip precisely
repeating every 1.3 seconds. Within a year though, scientists
realized aliens were not behind the regular signals. Instead, they came from
rapidly rotating stars. Pulsar became the catchy
name for the new phenomenon, short for pulsating star. A pulsar seems to blink on and
off because the rotating star is sending out beams of energy
from its magnetic field, which is not aligned with
its axis of rotation. We see the beam as
a flash of light when it passes across
our field of view. The beam coming
out of a pulsar works a lot like this
emergency beacon. Now, take a look
at how it flashes. It's not just
blinking on and off. Inside the housing the beacon
has a rotating reflector that sweeps the light
around 360 degrees. As long as we have line
of sight with the beam it sweeps by us every
time it goes around, but it looks like it's
flashing on and off. A rotating pulsar looks like
it is flashing on and off for the same reason. [music playing] NARRATOR: But a pulsar isn't
just any kind of rotating star. It's a rotating neutron
star, an exotic object created when a big, massive star
ends its life in a supernova. [booming] Astrophysicist Pat Slane
has a fascinating way to show us what's left over
after the supernova when the pressure of the
star's remaining core can no longer fight against
the force of gravity. What I'm going to demonstrate
here is what happens when we remove the air from the interior
of this 55-gallon drum and let the atmosphere of the Earth,
the weight of the air, crush it. This is similar to what
happens at the interior of a massive star
late in its life. When it loses its
pressure support the star collapses, and
there's a supernova explosion. [whirring] [clanking] NARRATOR: The crushed stellar
remnant becomes the neutron star, with a mass 1.4 times
our sun reduced to a sphere the size of Manhattan. It is one of the most
bizarre objects in nature. You have to understand that
a neutron star is matter barely holding up before it
collapses into a black hole. The gravity is so strong
that it has crushed electrons into the nucleus of an
atom and made neutrons. It's amazing. If you take something
like a sugar cube, for example, about
a cubic centimeter-- if this sugar cube were made
of neutron star material, it would weigh close
to a billion tons. Think of it as something
like 8,000 aircraft carriers in something that size-- incredibly dense objects. NARRATOR: The newly
created neutron star can't help having a high-speed spin. All stars that we know
about are already rotating. So when a massive star
compresses into a neutron star, the rotation is compressed also. It's just like an ice skater. When ice skater spins and
she pulls her arms in, she spins faster. NARRATOR: The
spinning neutron star is a massive natural
electric generator. Its spin creates a
powerful magnetic field. The magnetic force
grabs onto electrons and other atomic particles
and flings them into space at high speeds. High-speed particles
always emit radiation. And in pulsars, they're
coming out in beams. These are the pulses we see, but
we see them only when the beams are pointed in our direction. How many pulsars are known? It's something over 1,800, and
the number is growing rapidly because we continue to discover
new pulsars all the time. But the number of
pulsars that exist-- and these are all found in
our galaxy, the Milky Way-- is many, many times
larger than that because the beams
that are seen in radio primarily are very small. And so we only see a tiny
fraction of all the pulsars that are out there. NARRATOR: But each pulsar
has a completely different rotational speed. The slowest rotates once
every 9.437 seconds, and the fastest goes around
716 times every second. If we stood on its surface, we'd
be going more than 97 million miles per hour. That's about 10 million times
faster than we travel on Earth. Every pulsar has an
absolutely unique spin. It goes around at a given
rate, and that's just like a fingerprint
for an individual. So if you know what that
characteristic spin is, then you know what
that pulsar is. NARRATOR: Since all pulsars
have their own signatures, you can use them as tools
to determine your location in space, an idea that
has been used by NASA. Some of the spacecraft we've
sent into the outer parts of the solar system,
like Pioneer and Voyager, have had maps of space which
show our solar system's location relative to
the locations of a bunch of pulsars. [pulsing] NARRATOR: The pulsars in space
can be used to locate the Earth in the same way that our GPS
devices use multiple satellites to locate a position
on the ground. It's hoped one day another
race of space travelers will find one of the
spacecraft and read the map to learn where it came from. A sufficiently intelligent
alien could figure out where we are by measuring
all these same pulsars and figuring out where we
are in relation to them because each pulsar
has a unique period. NARRATOR: The unique
spin of each pulsar also makes them super
accurate astronomical clocks, keeping better time than
the best atomic clocks here on Earth. Pulsars are so
accurate because they're nature's ultimate flywheel. This is an ordinary bicycle
tire mounted on a repair rack here in this bicycle
shop, and this wheel is very much like a pulsar. Let's give it a spin. So you see the wheel is
rotating very smoothly. There's very little
to slow it down. Now, for a pulsar
in space there's almost nothing to slow it down. Now, notice that the wheel is
rotating about a couple times a second. That's the average speed of
rotation for an average pulsar. Now, of course, this wheel
is only a few feet across, whereas a real pulsar is
spinning at the same speed but it's the size of Manhattan. [music playing] NARRATOR: But
nothing is forever, and even pulsars slow down
over time, although they do it very slowly. The same bicycle wheel that
illustrates the pulsar's spin also demonstrates what
makes it slow down. Pulsars convert rotational
energy into radiation, and in the process
they have to slow down. Let's see how it works
with a bicycle wheel. Now, the wheel is
moving pretty quickly. If I put my hand to the rim I
can convert rotational energy to heat energy in my fingers. Ouch. Now the wheel has slowed down. In a real pulsar, it would
be more like the action of a feather than my hand
because pulsars lose energy very, very slowly. NARRATOR: A pulsar,
spinning once every second, may slow down by
about only 300ths of a second in a million years. Occasionally though, a pulsar
may actually speed up slightly in a phenomenon linked to a
neutron star's crust, a layer of matter 10 billion
times stronger than steel and yet subject to starquakes. Neutron stars are not
solids all the way through. They have a crust. That crust is incredibly
strong, but there are forces within
the neutron star that can occasionally
cause the crust to crack. And when it cracks a whole
neutron star readjusts itself, and it produces a change in the
rotation of the neutron star. We call that a glitch. The crust is cracked. There's been a starquake
on this neutron star. NARRATOR: Though the
strange world of pulsars includes intriguing events
like glitches and starquakes, you'd hardly know it from the
tiny blinks seen when they're captured by telescopes. But what happens when pulsars
are hurling deadly radiation into cosmic clouds after their
parent stars have ripped holes in the galaxy with their
massive explosions in space? What will their impact be on
any living beings in their path? [booming] NARRATOR: The deadly
explosions of supernovas are endlessly fascinating. They are the violent screams
of aging stars outraged at having to grow old. [rumbling] The powerful blasts would
do more than kill any living beings in their path. A supernova would wipe out
all traces of any civilization on a planet in orbit
around the exploding star. [booming] The galaxy is full of the
colorful after-effects of these explosions. They are gigantic clouds of
stellar debris called supernova remnants. And if you're
searching for a pulsar, that's the best place to look. Pulsars are actually
found in supernova remnants. That's because pulsars
are formed in a supernova, an exploding star. [music playing] NARRATOR: While some pulsars
speed away from or simply outlive their
supernova remnants, others remain
spinning inside them. There, they light up
the surrounding shell and create what's called
a pulsar wind nebula. The wind from a
pulsar is not quite like we think of on Earth,
which is air blowing. Instead, it's a wind made
of particles and radiation. But it's blowing out at very
high speeds, much faster than anything we have
here on Earth, high enough that it carries a lot of energy. And the energy interacts with
the material that's left over from the exploding star
to cause it to light up. By far the most spectacular
example of a pulsar wind nebula that we know about is
the Crab Nebula, which has a spinning neutron
star at its center, and that's what energizes
the whole thing. [music playing] The Crab Nebula is a
famous supernova remnant from the supernova that occurred
in the year 1054 AD, studied by Asian astronomers. NARRATOR: The
supernova itself could be seen in the sky for weeks
before fading away, only to be rediscovered nearly 700
years later as a supernova remnant, visible only
through telescopes. The pulsar in the Crab Nebula
was discovered in 1968, very soon after
the first pulsar, and it confirmed the theory that
pulsars came from supernovas. Seen from the Earth, the
pulsar in the Crab Nebula looks like an
insignificant speck. Before it was
identified as a pulsar, no one realized it was actually
blinking on and off 30 times a second. In a typical long exposure
photo from a telescope, it registers simply
as an ordinary star. Well, 30 times a second
is too fast for anyone to actually see the
Crab Pulsar blinking. Instead, we have to use a kind
of high-speed photographic technique called
a photon counter. And that's able to take pictures
fast enough to actually see the pulsar blinking on and off. It appears to be on when the
pulsar beam rotates toward us, and it's off when the
beam rotates away. [music playing] NARRATOR: What's incredible
is the power of the pulsar. Everything we see
in the Crab Nebula is glowing because of
the energy streaming out of that single
spinning neutron star. The neutron star in the
middle of the Crab Nebula has a diameter of
perhaps 10 miles, but it's lighting
up the gas around it for several light years. So this eensy beansy
thing is lighting up a tremendously large
region around it because of all the energetic
charged particles coming away from it. NARRATOR: The pulsar is
lighting up a supernova remnant six light years in diameter,
equivalent to nearly 380,000 astronomical units. An astronomical unit,
or an AU, is commonly used to describe
distance in the cosmos. Will W. of Denver, Colorado
wants to ask the universe just what an AU is. Will, that's a
useful thing to know. My snappy answer is that
an astronomical unit is one heck of a big apartment. But really, the
astronomical unit is the average distance
between the Earth and the Sun. Now, that's about 93 million
miles, or equivalently 150 million kilometers. [music playing] NARRATOR: The chaos deep
inside the Crab Nebula is revealed by
time-lapse pictures in both X-rays
and visible light. The spinning star's pulsar
wind creates shockwaves around its equator while
polar jets are shooting out in turbulent streams. So this is a very dynamic
system, an exciting one. And everybody in astronomy
studies the Crab Nebula. NARRATOR: Like most pulsars,
the one inside the Crab Nebula is gradually slowing down. But about 10% of all
pulsars have found a method of speeding up in a big way. They're called
millisecond pulsars. Millisecond pulsars are
what we call recycled pulsars. They used to be
ordinary pulsars. They stopped pulsing. And then because they were
in a binary system, that is, there was another star
nearby that they could steal some mass from, they're spun up. So their speed increases
to millisecond speeds. NARRATOR: Each time something
falls onto the pulsar, it gets a kick because
the stellar matter from the companion swirls onto
it instead of dropping straight to the surface. The rotating bicycle wheel
illustrates how the process makes the pulsar speed up. The wheel is
spinning, and my hand is like the matter from
the companion star. Because it has
rotational momentum, it swirls inward and strikes
the star like this, increasing its speed of rotation. It doesn't drop down like this. NARRATOR: In nature, the speeds
attained by millisecond pulsars are breathtaking. Pulsars spin several hundred
times a second, even up to maybe 1,000 times a
second for the fastest ones. That's very unusual, because
you're talking about something the size of maybe Manhattan
spinning a few hundred times a second. That would make
you pretty dizzy. NARRATOR: Even more exotic
than millisecond pulsars are the strange beasts
known as magnetars. Magnetars are extremely rare. In fact, we didn't even know
about any of them until 1979, and even then we weren't
sure exactly what we were looking at. Now we know of only
about 15 magnetars amongst the 400 billion
stars in our galaxy. NARRATOR: Pulsars are known
to have strong magnetic fields to begin with, but magnetars
take magnetism to the extreme. The magnetic field of
a magnetar is intense. It's 1,000 million million times
the magnetic field strength of the Earth. Now, if there were a
magnetar anywhere nearby, it would demagnetize all the
credit cards in the world. NARRATOR: But credit cards
wouldn't be of much use to humans, whose very
molecules may be pulled apart by a magnetar. [stretching sound] Magnetars have the
strongest magnetic field in the whole universe. It's unclear exactly
if humans could even live amongst a magnetic
field that strong because the magnetism tends
to pull water molecules apart into elongated structures. It's doubtful that
people could even live. [music playing] NARRATOR: And as if magnetars
and millisecond pulsars weren't bizarre enough in the
Milky Way's galactic sideshow, there are other freaks
even more mind blowing. What are the chances of
finding twin pulsars, pulsars with planets, and pulsars
joining the drummer of the Grateful Dead? [drumming] Take the click off. NARRATOR: Meet Mickey
Hart, longtime drummer who first gained fame
with the Grateful Dead and now makes music to the
beat of pulsars from space. I wanted to interact with
the fabric of the universe, the things that blew us into
creation, the seed sounds. So these electromagnetic
waves we've transferred into sonic waves. Pulsars are especially
interesting. [dramatic music] NARRATOR: Those
electromagnetic waves from pulsars reach
us most clearly in the form of radio
waves, sweeping across the sky in
the freakish beams that make pulsars stand out. Pulsars produce a
lot of radio waves, and that's quite
unlike normal stars. Normal stars shine mostly at
visible, optical wavelengths. So when you see a bright
radio source out there, it captures your attention. And if in addition it's
going beep, beep, beep, then it really captures
your attention. [beeping] We're also very lucky
that radio waves can make it through long distances
in our galaxy without being affected by
the intervening gas and dust. And they make it through
our own atmosphere as well without any trouble. NARRATOR: But perhaps what's
most exciting about pulsar radio beams is that they come
from hundreds of light years away. But pipe them into a set
of headphones or speakers and we can actually
listen to them. [low whirring] For slow ones, what you hear
is a bump out of the speaker every once-- every rotation. But for the highest
frequency ones, you hear a continuous tone. [pulsing] NARRATOR: This is the unearthly
sound of a typical pulsar, rotating 1.4 times each second. Converted to audio, the
pulsar's radio signal is a hypnotic, repetitious tick. But turn up the
frequency, and listen to this millisecond pulsar
spinning 174 times per second, so fast that its
ticks blend together to generate a ragged note
that's on the edge of turning into music. That's especially true when
we listen to the Vela Pulsar. [quick pulsing] The Vela Pulsar has a
terrific rhythm to it. It's hard to imagine this sound
coming from a spinning star of all things. [quick pulsing] It almost makes you want
to get up and dance. NARRATOR: The Vela Pulsar is
spinning with its cosmic beat at the center of a
giant supernova remnant, where its killer radiation
tears through the galactic gas and dust around it. The supernova exploded
11,000 years ago. And today, the pulsar
is most spectacular when seen in X-rays. Rotating 11 times a
second, time-lapse photos show that it's shooting out
a jet of material whipping through space like an
uncontrolled fire hose. [percussive beats] The unusual space beat
of the Vela Pulsar is a special turn
on for Mickey Hart, who's now making it the basis
for part of his latest project. [percussive beats] Well, Vela Pulsar,
it's really-- it's really made for composition
because it has a regular rhythm. [music playing] And sonically,
it's been enhanced. And it feels good, and you
can use in composition. So I went to the
Vela first thing. [dramatic music] NARRATOR: Hart used some simple
pulsar sounds during the Dead's 2009 concert tour, and
now he's building them into mind-bending tracks for an
upcoming sequel to his "Global Drum Project" album. His pulsar sounds came
from the SETI Institute, which leads the search for
extraterrestrial intelligence. [quick pulsing] I went to SETI, and
they led me to the sounds that I was looking for. I really hadn't delved into the
sounds of the universe before, and they just had the
motherlode of it there. And they shared it with me, and
then I turned it into music. [percussive music playing] Once all of these things
started to come my way, I realized that, you know,
the universe was singing. It's a spiritual thing for
me, as well as entertainment. I mean, it's fun working
with the cosmos, beyond fun. It's-- it's a deep
spiritual experience for me. [pulsing] [instrumental music] NARRATOR: The cosmic chorus
gets much bigger when it comes to a place called 47
Tucanae, a globular cluster of stars in the
southern constellation Tucana, the toucan. The cluster is 16,000
light years away, with two million stars packed
into a sphere 120 light years across. [melodic pulsing] Incredibly, 47 Tucanae has
22 millisecond pulsars, each generating its
own musical note in the bizarre stellar choir. To get a millisecond pulsar
producing a musical note, you need to start with the kind
of pulsar whipped up in speed by matter spilling onto it
from a binary companion star. [whirring] Well, in order
to do this you have to have lots of nearby stars. And what better place to do
that than in a star cluster? So something like 47 Tucanae,
which is a tremendously large collection of stars
nearby, is an ideal place to have neutron stars turn
into millisecond pulsars. NARRATOR: The collective tune
from the cluster's pulsars is a strangely haunting
song from space generated by their 22 unique
and different spins. [pulsing] While millisecond pulsars
throughout the galaxy usually have normal stars
as binary companions, there is one known binary system
that's a true freak because it has a pulsar paired
with another pulsar. Discovered in 2003, the
only known double pulsar formed when a millisecond
pulsar's companion went supernova. [booming] And now the two pulsars orbit
each other in a space so tight they would fit inside our sun. [dramatic music] While pulsars can have companion
stars or companion pulsars, things get even
stranger when we realize that even after a supernova
explosion some of them actually have planets. A pulsar is sort
of the last place you'd expect to find a planet,
because what happens to create a pulsar is a
supernova explosion. [booming] So if the original star
happened to have any planets around them, they probably
would've been blasted apart by the supernova. NARRATOR: But in 1992,
the very first planets discovered outside
our solar system were found around a pulsar. The giant radio telescope
in Arecibo, Puerto Rico was used to precisely measure
the timing of a pulsar 980 light years from Earth. It was changing, going a
little faster and a little slower. And that implied that
there was something else besides this pulsar itself. It was not isolated. It turned out to be,
indeed, a planet. NARRATOR: Calculations now
show there are at least three planets in orbit
around the pulsar, and a fourth is suspected. The pulsar supernova may
have destroyed its star's original planets, but new
ones formed, apparently out of debris left over
from the system's explosion. Pulsars are the embodiment
of extreme forces when it comes to
individual stars, but what happens when you ramp
up such power to the level of an entire galaxy? At that scale, we
find the quasars. What makes them outshine
everything else in the cosmos, and why do scientists say
that in the heart of each one there sits a monster? NARRATOR: While things
like pulsars and magnetars stand out as freakish
stars in the cosmos, even stranger objects lurk much
farther away where the quasars live. A quasar is a
blindingly bright core of a galaxy that has a giant
black hole in the center. And its extremely bright. It can be at its brightest
10 to 1,000 times brighter than all the stars
in the galaxy put together. NARRATOR: This Hubble
telescope photo proves just how bright a quasar can be. The two prominent objects
look almost the same, but one is only a star
perhaps 100 light years away while the other is a quasar
nine billion light years away. [low throbbing] Like pulsars, quasars
were first noticed by astronomers as strong
sources of radio waves. The very first was a radio
source called 3C 273. Well, what's a 3C 273? The Cambridge radio
telescope collected a catalog of radio-- bright radio sources
that were seen in the sky. And it was the third
Cambridge catalog, and item number 273 was
a bright radio source. People were trying to figure
out, what is this radio source? NARRATOR: When optical
telescopes were pointed at its position, all they saw
was what looked like a star. But then when it was realized
that this object was very far away, more than a billion
light years away, in fact-- --it meant that
their true power, the amount of energy
they put out per second, their wattage was enormous. Because to look bright
and yet be far away means that you've got to be
really a powerful object. What could it be? Now, 3C 273 was identified with
a rather bright, bluish star. So it looked star-like,
but stars don't generally emit radio waves. So it was called a
quasi-stellar radio source. [dramatic music] Quasi-stellar radio source
was just too long a name, and so it was
shortened to quasar. But golly, doesn't
that have a nice sound? Quasar is really a great term
because it implies something exotic and unusual. And that's really what
these objects are. They are huge black holes that
are eating material around them and radiating huge
amounts of light that can be seen almost all the way
across the observable universe. NARRATOR: The black hole
consuming galactic gas inside the quasar is
so violently ravenous, astronomers have given it
a frightening nickname. The black holes inside quasars
are often called monsters, and that's because
they're very massive. They're a million to a billion
times the mass of our sun. And they're voraciously
devouring the material around them, so they're sort
of behaving like monsters. NARRATOR: The quasar is said
to be powered by the black hole at a galaxy's center. The notion of something so
bright that it's also black seems like a
contradiction in terms. We know that black
holes are objects that are so dense, and massive,
and have such strong gravity that not even light
can escape from them. So that makes us wonder, how
can black holes power anything at all? And the answer is that gas, as
it falls into the black hole, can actually radiate
energy before it falls in. After it falls in, it's gone. The way this happens
is through friction. So if I take my hands and rub
them together very quickly, that produces a lot of heat. Now, the material that
falls into a black hole spirals in and rubs
against itself, and it's moving at
extremely high speeds. And so in the case
of a quasar, we have gas that's rubbing together
and moving at very high speeds. And so in doing so,
it can heat itself up to even millions of degrees,
which can cause it to glow very, very bright. [music playing] NARRATOR: Astronomers
are confident that there are giant black holes in
the center of all galaxies. So why aren't there quasars
in all galaxies too? To get a quasar,
you need two things. One, you need a huge, massive
black hole at the center of the galaxy, but you
also need a supply of gas to fall onto that black hole. If there isn't
enough material around, if the black hole has basically
eaten all its food around it, then there's nothing to shine. There's nothing to glow. It won't be a bright quasar. So there could be and probably
are black holes at the center of most galaxies, but if
there's no fuel for them they won't be quasars. NARRATOR: But there are
conditions in the universe that may make a quasar reignite
long after the gas in its host galaxy center gets used up. And one promising
way of doing this is by slamming two
galaxies together. We know that galaxies
collide, and when that happens it creates a big, cosmic
smash-up that drives material down to the center
of the galaxy. NARRATOR: The scenario could
apply to our own Milky Way galaxy, which is on a collision
course with Andromeda, the giant spiral next door. In five or six billion years
when the Andromeda galaxy starts merging with
the Milky Way galaxy, it's conceivable that
enough gas will be pushed toward the central
supermassive black holes that they'll turn into quasars. Now, the Andromeda
galaxy will probably be the brighter
of the two quasars because Andromeda has a
much more massive black hole than our Milky Way galaxy. If Andromeda turns into a
quasar when it's merging with the Milky Way
galaxy, it's conceivable that it'll be comparable to
the full moon in brightness when it's 10,000
light years away. Wow. NARRATOR: Even as close
as 10,000 light years away, we wouldn't see the
Andromeda quasar's disk as we can with the full moon. Instead, it will appear as
an intensely bright star, flickering due to atmospheric
fluctuations as all stars do. But incredibly,
if a quasar forms at the center of our own galaxy
we wouldn't see it at all. As bright as it may be, there is
so much dust between the Earth and the galactic
core, quasar's light would be hidden from us while
Andromeda's would light up the sky. If there is a local
quasar in our future, it could take any number
of different forms. They bombard space with
astrophysical jets and sound like mythical creatures with
names like blazars and DRAGNs. The stories they tell lead us
through the cosmological epic, where we arrive at
the beginning of time to find out how quasars
helped build the universe at its very birth. [booming] [booming] NARRATOR: In nearly
50 years of searching, astronomers have discovered
nearly a million quasars scattered throughout
the universe. And as it turns out, they come
in a wide variety of forms. A quasar is just one of
a family of objects called active galactic
nuclei, all of which are powered by material
falling onto huge black holes at the center of galaxies. The rate at which supermassive
black holes can swallow material in the
centers of galaxies can vary all over the place. The ones that don't
glow so brightly are called active galactic
nuclei, but not quasars. NARRATOR: One of the
most bizarre features of active galactic nuclei are
the high-speed jets of material shooting out from some of them. 3C 273, the first quasar to
be discovered, has a jet. It's only subtly apparent
in the optical image, but becomes more vivid when seen
by X-ray, infrared, and radio telescopes. Quasar jets are an
astronomical mystery. For years, scientists
have racked their brains to explain exactly how
they are generated. As with pulsars, a spinning
wheel in a bicycle shop illustrates the forces
they believe are at work. A vertical spoke
represents a force line in the quasar's magnetic field. The jets from quasars probably
require two things to form. The first is a disk of gas
that orbits the black hole. The second are
magnetic field lines that are anchored to the disk. Here's how we think it works. Charged particles love
magnetic field lines. So the particles get
tied to the field line, and as it rotates they get
blown upward away from the disk. Now, eventually the field
line will twist around, forcing the matter
into a tight column, or what astronomers call
an astrophysical jet. NARRATOR: The charged
particles in the jet are moving at high
speeds and can be seen from great distances. It's almost as if the quasar
were trying to get noticed by doing some advertising,
just as a local retailer might do on Earth. This advertising gadget
is called an air dancer. It gets our attention
here on Earth like the jet out of a quasar. And in fact, the way
it works is similar. [air blowing] The fabric rippler acts like
the twisted magnetic field generated by the quasar. The air inside follows
the walls of the rippler like the charged particles
following the magnetic field lines in the quasar. The big difference is that
here the air is flowing maybe 50 or 60 miles per hour. In a quasar jet, the particles
are moving at nearly the speed of light. NARRATOR: The air
dancer's display also extends only 12 feet
or so from its power source. A jet coming out of a quasar
or another active galactic nucleus, however, stretches far
into space, where it may turn into an amazing phenomenon
that astronomers call a DRAGN. DRAGN stands for double
radio source associated with an active galactic nucleus. That's sort of a
long term, but if you look at pictures of these
things DRAGN fits much better. What they are formed by is these
jets of material getting shot out from the black hole at
the center of the galaxy, slamming into the intergalactic
medium in between the galaxies, and forming these massive lobes
and hot spots that can extend to distances much larger than
the size of the galaxy itself. NARRATOR: The scale of
a DRAGN is mind bending. The typical one is about
1.5 million light years end to end, far, far larger
than the entire galaxy that's producing it. If the active galactic
nucleus were scaled down to the size of this
basketball, then the size of a DRAGN from one
radio lobe to the other would still be
absolutely enormous. It would be about the
size of the entire Earth. [music playing] NARRATOR: Most DRAGNs are linked
to quasar cousins called radio galaxies, since they are
strong sources of radio waves. But other members
of the same family are high-speed objects called
blazars, whose jets are pointed almost directly at
our line of sight, making them incredibly bright. And our line of sight
actually leads us to the most amazing discovery
about blazars, quasars, and radio galaxies. Who would have believed these
freaks are all basically alike? From studying all these
types of active galactic nuclei we now realize
that in some sense they all can be treated as
the same thing, just viewed in different ways. In particular, the
important thing is the viewing angle or the
angle of the jet of material relative to the angle
that we look at it. NARRATOR: The centers of active
galaxies are all very bright, but they may not seem that way
because the shining material at their cores can be
partially or completely hidden. This material we see is
surrounded by donut-shaped ring of material. That material--
gas, dust, clouds-- can block the
light from escaping from the central region
that's really the active part. And a radio galaxy is one of
those in which the donut is blocking our visibility
of the central core. But in the case of a
quasar we're looking down toward the hole in the
donut, and that allows us to see the material right
around the black hole that is the quasar. If this quasar has its jet
pointed toward us, then the jet itself becomes extremely bright. This is what we
would call a blazar. NARRATOR: All
three are the same. The only difference
is our point of view. But regardless of
our viewing angle, one thing they all have in
common is their great distance. The thing that
shocked us about quasars was how far away they are. They're so bright. And to see them that
bright at that distance, they must be titanic,
absolute monsters. So why are none of
these things nearby us? NARRATOR: The nearest quasar is
two billion light years away. The most distant ones are
13 billion light years away. Most quasars are seen
the vast distances from us. That means we're seeing them as
they were a long, long time ago in the past, when the
universe was very young. Quasars appear to be denizens
of the young universe. Galaxies early in
their formation seem to have produced
these black holes, and the black holes still had a
lot of material to eat shortly after being formed, so
they glowed as quasars. NARRATOR: The earliest quasars
date from shortly after the Big Bang itself, suggesting
they had an important role to play as the universe endured
its early growing pains. It's possible that these
supermassive black holes that we call quasars were part
of the process of creating structure in the universe. The process is not
completely understood. NARRATOR: So with most
of the quasars confined to the distant past we
study them intensely, hoping they'll
shed greater light on the origins of the cosmos. The early giant black holes
may have been among the engines that built the first
galaxies, giving form to the chaos of primeval gas
that would take shape in what we now see as the universe. [booming]
Very cool! I love Mickey Hart's approach to rhythm and drumming.
So insane he uses REAL space noises from 2 different types of pulsars/active galactic nuclei !
Check out Mickey's Mysterium Tremendum album, all of the compositions are based on the sounds he mentions in this video.
Here's a show he performed with his band showcasing many of the compositions he created.
https://www.youtube.com/watch?v=6_DW4t5zmIk