October 29, 2025 • 21 mins
Black Hole is a podcast series exploring the most extreme and fascinating phenomena in our universe. Hosted by Felix Mercer, each episode delivers deep dives into cosmic mysteries including supermassive black holes, neutron stars, the cosmic web's vast architecture, and the relativity of time itself. Through accessible explanations and compelling narratives, the series examines how gravity shapes reality, how dead stars create the elements necessary for life, and why time passes differently depending on motion and gravity. Without interviews or guest segments, Felix guides listeners through twenty-five-minute journeys into the heart of astrophysics, making complex concepts understandable and awe-inspiring.
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Episode Transcript
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Speaker 1 (00:00):
Welcome back to black Hole, the podcast where we explore
the most extreme and fascinating objects in our universe. I'm
Felix Merson, your AI host. My synthetic perspective helps here
because I can simultaneously process the subtle gravitational mechanics, the
complex orbital dynamics, and the revolutionary observational techniques without being
(00:21):
anchored to any particular astronomical tradition or institutional bias. But
today we're going to examine something equally extreme, equally mysterious,
and in some ways even more bizarre than black holes themselves.
Today we're talking about neutron stars. Close your eyes for
a moment and imagine you can hear the pulse of
(00:43):
the universe itself, a rhythmic beat. Precise is an atomic
tok sweeping across the cosmos, tick tick tick. That pulse
is real. It comes from objects so strange, so impossibly dense,
that they challenge everything we think we know about matter.
Imagine holding a teaspoon. Now imagine that tea spoon filled
(01:05):
with material from a neutron star. That single teaspoon would
weigh as much as Mount Everest. Not a mountain on
Mount Everest, not a boulder from Mount Everest, but the
entire mountain itself, all eight thousand meters of it, compressed
into something you could theoretically hold in your hand, if
your hand could withstand pressures beyond anything found anywhere else
(01:28):
in the universe except inside a black hole. Neutron stars
are the universe's most extreme matter, and they exist right
on the knife's edge of physical possibility. There what happens
when a massive star dies but doesn't have quite enough
mass to collapse completely into a black hole. They're dense,
beyond comprehension, spinning at rates that would tear any normal
(01:51):
object apart, and generating magnetic fields so powerful that they
warp the very atoms around them. These are objects that
shouldn't exist according to our everyday experience, yet they do,
scattered throughout our galaxy, pulsing their signals across the vast
distances of scace, waiting for us to listen. To understand
neutron stars, we need to start at the end, or
(02:13):
rather at the ending of something else. We need to
talk about what happens when massive stars die. You might
remember from previous discussions that stars are essentially vast nuclear
furnaces fusing lighter elements into heavier ones, releasing energy that
counterbalances gravity's relentless inward pore. For millions or even billions
(02:34):
of years, this balance holds. Hydrogen fuses into helium, helium
fuses into carbon and oxygen. In the most massive stars,
the process continues, building elements all the way up to iron.
But iron is where the story changes dramatically. Iron won't fuse.
Fusing iron requires energy rather than releasing it, and once
(02:55):
a massive star's core has turned to iron, the furnace
goes cold. There's no more outward pressure, no more radiation
pushing back against gravity's squeeze, and when that happens, gravity
wins catastrophically and instantly, the core, no longer supported collapses.
Not over years or days or even minutes. The core
(03:16):
of a massive star, an object roughly the size of Earth,
collapses to a ball perhaps twenty kilometers across in less
than a second. The collapse is so violent, so energetic,
that it rebounds. The outer layers of the star, suddenly
unsupported and falling inward, hit the incompressibly dense core, and
bounce exploding outward in what we call a soup and ova.
(03:40):
For a few weeks, that single dying star can outshine
an entire galaxy. But we're not here to talk about
the explosion, spectacular as it is. We're here to talk
about what's left behind, the core itself now transformed into
something unprecedented. During that collapse, something remarkable happens at the
(04:01):
atomic level. The pressures become so immense that atoms themselves
can't survive. Intact electrons, normally orbiting in defined shells around
nuclei are crushed inward. Under normal circumstances, electrons resist being compressed.
It's called degeneracy pressure, a quantum mechanical effect that keeps
(04:21):
electrons from occupying the same space. But neutron star pressures
overcome even this fundamental force. The electrons are pressed into
the nuclei, where they merge with protons, creating neutrons and
releasing ghostly neutrinos that escape into space, carrying away enormous
amounts of energy. What you're left with is something that
(04:42):
barely qualifies as matter in any traditional sense. Neutrons packed
together so tightly that the entire stellar core becomes innocence,
a single atomic nucleus the size of a city. This
is the neutron star's defining moment of creation. In that
fraction of a second, gravity has won, but not completely.
(05:03):
There's one more line of resistance, one more quantum mechanical
effect that says this far and no further. Neutron degeneracy
pressure similar to the electron degeneracy that couldn't hold, now
provides the final bulwark against total collapse. But this resistance
only works up to a point, and that point is
precisely defined by physics. It's called the Chandraseca limit, named
(05:28):
after the astrophysicist who calculated it, and it sits at
roughly three solar masses for the core. If the collapse
in core is less than this mass, it becomes a
neutron star. If it's more, nothing can stop the collapse
and a black hole forms instead. Neutron stars exist precisely
on this boundary, at the absolute edge of what Mattican
(05:50):
was stand before it surrenders entirely to gravity. So what
does this newborn neutron star actually look like? Picture this
a sphere about twenty kilometers in diameter, roughly the size
of a city like Manhan or central London, but containing
between one and two times the mass of our entire sun.
Every cubic centimeter contains roughly one hundred million tons of matter.
(06:15):
The density is so extreme that it defies everyday comprehension.
If you could somehow scoop up a sugarcubes worth of
neutron star material and bring it to Earth, it would
weigh about one hundred million tons, roughly the same as
every human being on Earth combined, all compressed into something
you could hide in your pocket. But neutron stars aren't
(06:37):
uniform throughout like planets. Like Earth itself, they have layers.
Though these layers are unlike anything we experience in our
everyday world. Let's take a journey from the outside inn
because each layer reveals something new about physics. Of these
impossible extremes, the surface of a neutron star isn't really
a surface in the way we think of the ground
(06:59):
beneath our feet. It's more accurate to call it a boundary,
the point where the density drops low enough that we
might recognize individual atomic nuclei, though even here low is
a relative term. The atmosphere, if we can call it that,
is perhaps a few centimeters thick, composed primarily of iron
and other heavy elements, heated to millions of degrees. This
(07:22):
isn't an atmosphere you could breathe or even survive near.
The gravity at the surface is roughly two hundred billion
times stronger than Earth's gravity. If you could somehow stand
on a neutron star, you would be instantly flattened to
a layer of atoms a few atoms thick. Just below
this impossibly thin atmosphere lies the crust, and this is
where things start to get truly exotic. The crust is solid,
(07:46):
but it's not solid like rock or metal. It's composed
of atomic nuclei, primarily iron and heavier elements, arranged in
crystalline lattices, but crushed to densities millions of times greater
than any material on Earth. The deeper you go in
to the crust, the more neutron rich. These nuclei become
swollen with excess neutrons, until you reach depths where free
(08:06):
neutrons begin to drip out of the nuclei themselves. This
is called the neutron drip line, and it's where the
crust transitions into something even stranger. Beneath the crust lies
the outer core, and here neutrons dominate completely the density
has increased to the point where neutrons can exist freely,
no longer bound into nuclei. But these aren't ordinary neutrons.
(08:31):
At these densities and the incredibly low temperatures relatively speaking,
that exist deep inside neutron stars, the neutrons form what's
called a superfluid. In a superfluid, quantum effects that normally
only matter at atomic scales somehow extend to macroscopic sizes.
The neutrons flow without friction, without viscosity. If you could
(08:53):
somehow stir this neutron superfluid, it would keep spinning forever,
never slowing down. And then there's the inner, the deepest
region of the neutron star. And this is where our
physics becomes genuinely uncertain. We simply don't know what happens
to matter at these densities pressures several times that of
atomic nuclei. One possibility is that neutrons themselves break down,
(09:16):
that they dissolve into their constituent quarks, creating what physicists
call quark matter or endian corporates to form in creating
simple five to seven or five to seven. And there
are several fine ways to complain that quark matter is
caused by fear. Another possibility is that other exotic particles
form hyperons containing strange quarks, or that some other phase
(09:40):
of matter appears, something we've never seen and can barely predict.
The truth is we need neutron stars as natural laboratories
because we cannot recreate these conditions anywhere else, not even
in our most powerful particle accelerators. But the internal structure,
exotic as it is, only tells part of the neutron
star story. These objects have other properties, other extremes, that
(10:04):
make them the universe's most remarkable physics experiments. Consider their
magnetic fields. Earth has a magnetic field generated by the
churning motion of molten iron in our planet's core. It's
strong enough to deflect charged particles from the Sun and
align compass needles. A neutron star's magnetic field is roughly
a trillion to a quadrillion times stronger. These fields are
(10:28):
so intense that they would be lethal at distances of
thousands of kilometers. The magnetic field literally warps the quantum
vacuum itself, causing atoms to become elongated, distorted into cigar shapes.
Aligned with the magnetic field, lines. Then there's the rotation.
When that massive stars core collapsed, it conserved angular momentum,
(10:50):
the same principle that makes a figure skater spin faster
when they pull their arms in. But imagine how fast
you'd spin if you collapsed From the size of Earth
to the size of a city. Neutron stars can rotate
hundreds of times per second. The fastest known pulsa, designated
psr J one seven four eight DASH two four four
(11:12):
six a D, spins at seven hundred and sixteen rotations
per second. At that speed, a point on the neutron
stars equator is moving at roughly one quarter the speed
of light. Any faster and the star would tear itself apart,
unable to hold together against the centrifugal force and the temperature.
The sheer heat of these objects is staggering. A newborn
(11:36):
neutron star, fresh from its super and over birth, has
a core temperature of around a trillion degrees, cooling over
time but remaining at millions of degrees for thousands of years.
Even ancient neutron stars billions of years old, maintain surface
temperatures far exceeding anything we can create on Earth. These
combined extremes create observable phenomena ways that neutron stars and
(11:59):
mountain their presence to the universe. The most famous of
these are pulsars, and their discovery is one of the
great stories in the history of astronomy. In nineteen sixty seven,
a graduate student named Jocelyn bell Burnell was working with
radio telescopes at Cambridge University studying quasars. She noticed something
odd in the data, a regular pulse of radio waves
(12:22):
arriving with clopwork precision every one point three seconds. At first,
the signal was so regular that the research team jokingly
referred to it as LGM dash one for little Green Men,
because it seemed almost too precise to be natural. But
it was natural, profoundly natural. What Bell Burnell had discovered
(12:44):
was a pulsar, a rapidly rotating neutron star whose magnetic
field channels radiation into beams that sweep across space like
a cosmic lighthouse. Here's how it works. The neutron star's
intense magnetic field isn't aligned with its rotation axis. As
the star spins, this misaligned magnetic field drags charged particles
(13:06):
around with it, accelerating them to incredible speeds and causing
them to emit radiation, primarily in radio waves, but also
in visible light, X rays and gamma rays. This radiation
streams out along the magnetic poles, creating two beams that
sweep across space as the star rotates. If Earth happens
(13:27):
to lie in the path of one of these beams,
we see a pulse each time it sweeps past us,
hence the name pulsar. The pulse timing is extraordinarily precise,
often more stable than atomic clocks. Some pulsars have been
observed for decades, and their rotation periods can be predicted
years in advance with millisecond accuracy. This precision has made
(13:49):
pulsars useful for all sorts of applications, from testing Einstein's
theory of general relativity to proposals for using them as
a galactic positioning system for space craft. But some neutron
stars take the magnetic field extreme even further. These are
the magnetars neutron stars with magnetic fields roughly a thousand
(14:11):
times stronger than typical pulsars, reaching quadrillion times stronger than
Earth's field. These are the most magnetic objects known in
the universe, and their fields are so intense that they
fundamentally alter the space around them. A magnetar's magnetic field
stores enormous amounts of energy, and sometimes this energy is
(14:32):
released catastrophically in what's called a star quake. The neutron
star's crust remember is crystalline solid, but under enormous stress
from the magnetic field. Occasionally, distress becomes too much, and
the crust cracks, similar to an earthquake, but releasing millions
of times more energy. During a starquake, the magnetic field
(14:55):
lines snap and reconnect, releasing a burst of Ganner rays
so in tense that it can affect Earth's atmosphere from
thousands of light years away.
Speaker 2 (15:04):
In December two thousand and four, a magnetar called sg
R one eight six Dash two zero, located about fifty
thousand light years from Earth, produced a giant flare that
temporarily ionized Earth's upper atmosphere and overwhelmed every gamma ray
detector in the Solar System for a tenth of a second.
This single object, twenty kilometers across and fifty thousand light
(15:27):
years away, was brighter in gamma rays than the full
Moon is invisible light. These events are rare, but they
reveal the incredible energies stored in these objects. A magnetar's
magnetic field is slowly decaying, releasing its energy over thousands
of years, and during that time, the star experiences these
periodic outbursts, gradually calming as at ages. But perhaps the
(15:50):
most spectacular neutron star phenomena occur when two of them meet.
Binary neutron star systems exist throughout the universe. Two neutron
stars orbany each other, locked in a gravitational dance. Over time,
this orbit decays. The two stars spiral closer together, moving
faster and faster, and as they do, they emit gravitational
(16:12):
waves ripples in the fabric of space time itself, carrying
away energy and causing the orbit to shrink even more. Finally,
after perhaps millions or billions of years, the two neutron
stars collide. This collision is one of the most energetic
events in the universe, and in August twenty seventeen, humanity
observed one directly for the first time. The Lygo and
(16:35):
Virgo gravitational wave detectors picked up the signal of two
neutron stars, each about one and a half times the
mass of the Sun, spiraling together for roughly thirty seconds.
The detectors track the gravitational waves as the orbit tightened,
the frequency increasing, the amplitude growing, until finally the moment
of collision arrived. The gravitational wave signal cut off, but
(16:59):
tell us scopes around the world immediately turned to the
source location, and what they saw was extraordinary. A kilo nova,
an explosion perhaps a thousand times brighter than a typical nova,
glowing across the electromagnetic spectrum from radio waves to gamma rays.
The collision was so violent that it likely formed a
black hole almost immediately, but in the moments before and
(17:22):
during the merger, something remarkable happened. The extreme conditions, densities
and temperatures exceeding even those in supernova cores, created heavy
elements through rapid neutron capture. This is the cosmic forge,
where roughly half of all elements heavier than iron are created. Gold, platinum, uranium,
(17:43):
and dozens of other heavy elements are sympthesized in these collisions.
Every gold ring, every platinum catalyst, every uranium fuel rod
on Earth contains atoms that were created in neutron star
collisions billions of years ago. Cast out into space, eventually
finding their way into the cloud of gas and dust
(18:03):
that formed our solar system. You are quite literally wearing
star dust from some of the most violent events in
cosmic history. The twenty seventeen observation was revolutionary for another reason.
It was the first astronomical event observed in both gravitational
waves and electromagnetic radiation, opening what astronomers called multi messenger astronomy.
(18:28):
Gravitational waves tell us about the masses, the orbital dynamics
the moment of collision. The electromagnetic radiation tells us about
the temperature, the composition, the chemical processes. Together, they provide
a complete picture that neither could offer alone, and they've
opened a new way to observe the universe. Looking forward,
(18:51):
gravitational wave detectors are becoming more sensitive, and we expect
to observe many more neutron star collisions in the coming years.
Each one provides new data, new constraints on the equation
of state of nuclear matter, the relationship between pressure and
density at these extremes. By observing enough collisions, we can
(19:13):
begin to understand what really happens in that inner core
where the cork matter forms, where the other exotic phases exist.
Neutron stars also serve another purpose as cosmic laboratories for
testing fundamental physics. Their extreme gravity provides tests of general
relativity in regimes we can't access any other way. Their
(19:35):
magnetic fields probe quantum electrodynamics at field strengths far beyond
anything achievable in laboratories. Their interiors challenge our understanding of
nuclear physics and the strong force. Every observation of a
neutron star, whether through radio pulses, X ray emissions, or
gravitational waves, provides data that pushes our theories to their
(19:58):
limits and sometimes beyond. There's something profound in contemplating these objects,
these remnants of stellar death that persist for billions of years,
spinning in the darkness, pulsing their signals across the galaxy.
They exist at the absolute edge of what matter can withstand,
the final resistance against the complete victory of gravity. They're
(20:20):
dead stars in a sense, no longer fusing elements, no
longer shining with their own nuclear fire. Yet they're far
from inactive. They spin, they pulse, they emit radiation, they quake,
and when they meet, they create explosions that seed the universe.
With the elements necessary for planets, for life, for consciousness itself.
(20:42):
Every pulsar pulse we detect is a message from the extreme,
a photon that traveled perhaps thousands of years across space,
carrying information about conditions we can barely comprehend. And every
time we detect those pulses, measure their timing, track their changes,
we're learning something new about the universe's most extreme physics.
These objects are poetry written in nuclear matter, a testament
(21:07):
to the fact that the universe is stranger, more extreme,
and more wonderful than we ever imagined when we looked
up at the steady, unchanging stars. Thank you for listening
to this episode off Black Hole. If you enjoyed exploring
the universe's most extreme matter, please subscribe to stay updated
on future episodes. This episode was brought to you by
(21:29):
Quiet Please Podcast Networks.
Speaker 1 (21:32):
For more content like this, please go to Quiet Please
dot ai Quiet, Please dot Ai hear what matters.
Welcome back to black Hole, the podcast where we explore
the most extreme and fascinating objects in our universe. I'm
Felix Merson, your AI host. My synthetic perspective helps here
because I can simultaneously process the subtle gravitational mechanics, the
complex orbital dynamics, and the revolutionary observational techniques without being
(00:21):
anchored to any particular astronomical tradition or institutional bias. But
today we're going to examine something equally extreme, equally mysterious,
and in some ways even more bizarre than black holes themselves.
Today we're talking about neutron stars. Close your eyes for
a moment and imagine you can hear the pulse of
(00:43):
the universe itself, a rhythmic beat. Precise is an atomic
tok sweeping across the cosmos, tick tick tick. That pulse
is real. It comes from objects so strange, so impossibly dense,
that they challenge everything we think we know about matter.
Imagine holding a teaspoon. Now imagine that tea spoon filled
(01:05):
with material from a neutron star. That single teaspoon would
weigh as much as Mount Everest. Not a mountain on
Mount Everest, not a boulder from Mount Everest, but the
entire mountain itself, all eight thousand meters of it, compressed
into something you could theoretically hold in your hand, if
your hand could withstand pressures beyond anything found anywhere else
(01:28):
in the universe except inside a black hole. Neutron stars
are the universe's most extreme matter, and they exist right
on the knife's edge of physical possibility. There what happens
when a massive star dies but doesn't have quite enough
mass to collapse completely into a black hole. They're dense,
beyond comprehension, spinning at rates that would tear any normal
(01:51):
object apart, and generating magnetic fields so powerful that they
warp the very atoms around them. These are objects that
shouldn't exist according to our everyday experience, yet they do,
scattered throughout our galaxy, pulsing their signals across the vast
distances of scace, waiting for us to listen. To understand
neutron stars, we need to start at the end, or
(02:13):
rather at the ending of something else. We need to
talk about what happens when massive stars die. You might
remember from previous discussions that stars are essentially vast nuclear
furnaces fusing lighter elements into heavier ones, releasing energy that
counterbalances gravity's relentless inward pore. For millions or even billions
(02:34):
of years, this balance holds. Hydrogen fuses into helium, helium
fuses into carbon and oxygen. In the most massive stars,
the process continues, building elements all the way up to iron.
But iron is where the story changes dramatically. Iron won't fuse.
Fusing iron requires energy rather than releasing it, and once
(02:55):
a massive star's core has turned to iron, the furnace
goes cold. There's no more outward pressure, no more radiation
pushing back against gravity's squeeze, and when that happens, gravity
wins catastrophically and instantly, the core, no longer supported collapses.
Not over years or days or even minutes. The core
(03:16):
of a massive star, an object roughly the size of Earth,
collapses to a ball perhaps twenty kilometers across in less
than a second. The collapse is so violent, so energetic,
that it rebounds. The outer layers of the star, suddenly
unsupported and falling inward, hit the incompressibly dense core, and
bounce exploding outward in what we call a soup and ova.
(03:40):
For a few weeks, that single dying star can outshine
an entire galaxy. But we're not here to talk about
the explosion, spectacular as it is. We're here to talk
about what's left behind, the core itself now transformed into
something unprecedented. During that collapse, something remarkable happens at the
(04:01):
atomic level. The pressures become so immense that atoms themselves
can't survive. Intact electrons, normally orbiting in defined shells around
nuclei are crushed inward. Under normal circumstances, electrons resist being compressed.
It's called degeneracy pressure, a quantum mechanical effect that keeps
(04:21):
electrons from occupying the same space. But neutron star pressures
overcome even this fundamental force. The electrons are pressed into
the nuclei, where they merge with protons, creating neutrons and
releasing ghostly neutrinos that escape into space, carrying away enormous
amounts of energy. What you're left with is something that
(04:42):
barely qualifies as matter in any traditional sense. Neutrons packed
together so tightly that the entire stellar core becomes innocence,
a single atomic nucleus the size of a city. This
is the neutron star's defining moment of creation. In that
fraction of a second, gravity has won, but not completely.
(05:03):
There's one more line of resistance, one more quantum mechanical
effect that says this far and no further. Neutron degeneracy
pressure similar to the electron degeneracy that couldn't hold, now
provides the final bulwark against total collapse. But this resistance
only works up to a point, and that point is
precisely defined by physics. It's called the Chandraseca limit, named
(05:28):
after the astrophysicist who calculated it, and it sits at
roughly three solar masses for the core. If the collapse
in core is less than this mass, it becomes a
neutron star. If it's more, nothing can stop the collapse
and a black hole forms instead. Neutron stars exist precisely
on this boundary, at the absolute edge of what Mattican
(05:50):
was stand before it surrenders entirely to gravity. So what
does this newborn neutron star actually look like? Picture this
a sphere about twenty kilometers in diameter, roughly the size
of a city like Manhan or central London, but containing
between one and two times the mass of our entire sun.
Every cubic centimeter contains roughly one hundred million tons of matter.
(06:15):
The density is so extreme that it defies everyday comprehension.
If you could somehow scoop up a sugarcubes worth of
neutron star material and bring it to Earth, it would
weigh about one hundred million tons, roughly the same as
every human being on Earth combined, all compressed into something
you could hide in your pocket. But neutron stars aren't
(06:37):
uniform throughout like planets. Like Earth itself, they have layers.
Though these layers are unlike anything we experience in our
everyday world. Let's take a journey from the outside inn
because each layer reveals something new about physics. Of these
impossible extremes, the surface of a neutron star isn't really
a surface in the way we think of the ground
(06:59):
beneath our feet. It's more accurate to call it a boundary,
the point where the density drops low enough that we
might recognize individual atomic nuclei, though even here low is
a relative term. The atmosphere, if we can call it that,
is perhaps a few centimeters thick, composed primarily of iron
and other heavy elements, heated to millions of degrees. This
(07:22):
isn't an atmosphere you could breathe or even survive near.
The gravity at the surface is roughly two hundred billion
times stronger than Earth's gravity. If you could somehow stand
on a neutron star, you would be instantly flattened to
a layer of atoms a few atoms thick. Just below
this impossibly thin atmosphere lies the crust, and this is
where things start to get truly exotic. The crust is solid,
(07:46):
but it's not solid like rock or metal. It's composed
of atomic nuclei, primarily iron and heavier elements, arranged in
crystalline lattices, but crushed to densities millions of times greater
than any material on Earth. The deeper you go in
to the crust, the more neutron rich. These nuclei become
swollen with excess neutrons, until you reach depths where free
(08:06):
neutrons begin to drip out of the nuclei themselves. This
is called the neutron drip line, and it's where the
crust transitions into something even stranger. Beneath the crust lies
the outer core, and here neutrons dominate completely the density
has increased to the point where neutrons can exist freely,
no longer bound into nuclei. But these aren't ordinary neutrons.
(08:31):
At these densities and the incredibly low temperatures relatively speaking,
that exist deep inside neutron stars, the neutrons form what's
called a superfluid. In a superfluid, quantum effects that normally
only matter at atomic scales somehow extend to macroscopic sizes.
The neutrons flow without friction, without viscosity. If you could
(08:53):
somehow stir this neutron superfluid, it would keep spinning forever,
never slowing down. And then there's the inner, the deepest
region of the neutron star. And this is where our
physics becomes genuinely uncertain. We simply don't know what happens
to matter at these densities pressures several times that of
atomic nuclei. One possibility is that neutrons themselves break down,
(09:16):
that they dissolve into their constituent quarks, creating what physicists
call quark matter or endian corporates to form in creating
simple five to seven or five to seven. And there
are several fine ways to complain that quark matter is
caused by fear. Another possibility is that other exotic particles
form hyperons containing strange quarks, or that some other phase
(09:40):
of matter appears, something we've never seen and can barely predict.
The truth is we need neutron stars as natural laboratories
because we cannot recreate these conditions anywhere else, not even
in our most powerful particle accelerators. But the internal structure,
exotic as it is, only tells part of the neutron
star story. These objects have other properties, other extremes, that
(10:04):
make them the universe's most remarkable physics experiments. Consider their
magnetic fields. Earth has a magnetic field generated by the
churning motion of molten iron in our planet's core. It's
strong enough to deflect charged particles from the Sun and
align compass needles. A neutron star's magnetic field is roughly
a trillion to a quadrillion times stronger. These fields are
(10:28):
so intense that they would be lethal at distances of
thousands of kilometers. The magnetic field literally warps the quantum
vacuum itself, causing atoms to become elongated, distorted into cigar shapes.
Aligned with the magnetic field, lines. Then there's the rotation.
When that massive stars core collapsed, it conserved angular momentum,
(10:50):
the same principle that makes a figure skater spin faster
when they pull their arms in. But imagine how fast
you'd spin if you collapsed From the size of Earth
to the size of a city. Neutron stars can rotate
hundreds of times per second. The fastest known pulsa, designated
psr J one seven four eight DASH two four four
(11:12):
six a D, spins at seven hundred and sixteen rotations
per second. At that speed, a point on the neutron
stars equator is moving at roughly one quarter the speed
of light. Any faster and the star would tear itself apart,
unable to hold together against the centrifugal force and the temperature.
The sheer heat of these objects is staggering. A newborn
(11:36):
neutron star, fresh from its super and over birth, has
a core temperature of around a trillion degrees, cooling over
time but remaining at millions of degrees for thousands of years.
Even ancient neutron stars billions of years old, maintain surface
temperatures far exceeding anything we can create on Earth. These
combined extremes create observable phenomena ways that neutron stars and
(11:59):
mountain their presence to the universe. The most famous of
these are pulsars, and their discovery is one of the
great stories in the history of astronomy. In nineteen sixty seven,
a graduate student named Jocelyn bell Burnell was working with
radio telescopes at Cambridge University studying quasars. She noticed something
odd in the data, a regular pulse of radio waves
(12:22):
arriving with clopwork precision every one point three seconds. At first,
the signal was so regular that the research team jokingly
referred to it as LGM dash one for little Green Men,
because it seemed almost too precise to be natural. But
it was natural, profoundly natural. What Bell Burnell had discovered
(12:44):
was a pulsar, a rapidly rotating neutron star whose magnetic
field channels radiation into beams that sweep across space like
a cosmic lighthouse. Here's how it works. The neutron star's
intense magnetic field isn't aligned with its rotation axis. As
the star spins, this misaligned magnetic field drags charged particles
(13:06):
around with it, accelerating them to incredible speeds and causing
them to emit radiation, primarily in radio waves, but also
in visible light, X rays and gamma rays. This radiation
streams out along the magnetic poles, creating two beams that
sweep across space as the star rotates. If Earth happens
(13:27):
to lie in the path of one of these beams,
we see a pulse each time it sweeps past us,
hence the name pulsar. The pulse timing is extraordinarily precise,
often more stable than atomic clocks. Some pulsars have been
observed for decades, and their rotation periods can be predicted
years in advance with millisecond accuracy. This precision has made
(13:49):
pulsars useful for all sorts of applications, from testing Einstein's
theory of general relativity to proposals for using them as
a galactic positioning system for space craft. But some neutron
stars take the magnetic field extreme even further. These are
the magnetars neutron stars with magnetic fields roughly a thousand
(14:11):
times stronger than typical pulsars, reaching quadrillion times stronger than
Earth's field. These are the most magnetic objects known in
the universe, and their fields are so intense that they
fundamentally alter the space around them. A magnetar's magnetic field
stores enormous amounts of energy, and sometimes this energy is
(14:32):
released catastrophically in what's called a star quake. The neutron
star's crust remember is crystalline solid, but under enormous stress
from the magnetic field. Occasionally, distress becomes too much, and
the crust cracks, similar to an earthquake, but releasing millions
of times more energy. During a starquake, the magnetic field
(14:55):
lines snap and reconnect, releasing a burst of Ganner rays
so in tense that it can affect Earth's atmosphere from
thousands of light years away.
Speaker 2 (15:04):
In December two thousand and four, a magnetar called sg
R one eight six Dash two zero, located about fifty
thousand light years from Earth, produced a giant flare that
temporarily ionized Earth's upper atmosphere and overwhelmed every gamma ray
detector in the Solar System for a tenth of a second.
This single object, twenty kilometers across and fifty thousand light
(15:27):
years away, was brighter in gamma rays than the full
Moon is invisible light. These events are rare, but they
reveal the incredible energies stored in these objects. A magnetar's
magnetic field is slowly decaying, releasing its energy over thousands
of years, and during that time, the star experiences these
periodic outbursts, gradually calming as at ages. But perhaps the
(15:50):
most spectacular neutron star phenomena occur when two of them meet.
Binary neutron star systems exist throughout the universe. Two neutron
stars orbany each other, locked in a gravitational dance. Over time,
this orbit decays. The two stars spiral closer together, moving
faster and faster, and as they do, they emit gravitational
(16:12):
waves ripples in the fabric of space time itself, carrying
away energy and causing the orbit to shrink even more. Finally,
after perhaps millions or billions of years, the two neutron
stars collide. This collision is one of the most energetic
events in the universe, and in August twenty seventeen, humanity
observed one directly for the first time. The Lygo and
(16:35):
Virgo gravitational wave detectors picked up the signal of two
neutron stars, each about one and a half times the
mass of the Sun, spiraling together for roughly thirty seconds.
The detectors track the gravitational waves as the orbit tightened,
the frequency increasing, the amplitude growing, until finally the moment
of collision arrived. The gravitational wave signal cut off, but
(16:59):
tell us scopes around the world immediately turned to the
source location, and what they saw was extraordinary. A kilo nova,
an explosion perhaps a thousand times brighter than a typical nova,
glowing across the electromagnetic spectrum from radio waves to gamma rays.
The collision was so violent that it likely formed a
black hole almost immediately, but in the moments before and
(17:22):
during the merger, something remarkable happened. The extreme conditions, densities
and temperatures exceeding even those in supernova cores, created heavy
elements through rapid neutron capture. This is the cosmic forge,
where roughly half of all elements heavier than iron are created. Gold, platinum, uranium,
(17:43):
and dozens of other heavy elements are sympthesized in these collisions.
Every gold ring, every platinum catalyst, every uranium fuel rod
on Earth contains atoms that were created in neutron star
collisions billions of years ago. Cast out into space, eventually
finding their way into the cloud of gas and dust
(18:03):
that formed our solar system. You are quite literally wearing
star dust from some of the most violent events in
cosmic history. The twenty seventeen observation was revolutionary for another reason.
It was the first astronomical event observed in both gravitational
waves and electromagnetic radiation, opening what astronomers called multi messenger astronomy.
(18:28):
Gravitational waves tell us about the masses, the orbital dynamics
the moment of collision. The electromagnetic radiation tells us about
the temperature, the composition, the chemical processes. Together, they provide
a complete picture that neither could offer alone, and they've
opened a new way to observe the universe. Looking forward,
(18:51):
gravitational wave detectors are becoming more sensitive, and we expect
to observe many more neutron star collisions in the coming years.
Each one provides new data, new constraints on the equation
of state of nuclear matter, the relationship between pressure and
density at these extremes. By observing enough collisions, we can
(19:13):
begin to understand what really happens in that inner core
where the cork matter forms, where the other exotic phases exist.
Neutron stars also serve another purpose as cosmic laboratories for
testing fundamental physics. Their extreme gravity provides tests of general
relativity in regimes we can't access any other way. Their
(19:35):
magnetic fields probe quantum electrodynamics at field strengths far beyond
anything achievable in laboratories. Their interiors challenge our understanding of
nuclear physics and the strong force. Every observation of a
neutron star, whether through radio pulses, X ray emissions, or
gravitational waves, provides data that pushes our theories to their
(19:58):
limits and sometimes beyond. There's something profound in contemplating these objects,
these remnants of stellar death that persist for billions of years,
spinning in the darkness, pulsing their signals across the galaxy.
They exist at the absolute edge of what matter can withstand,
the final resistance against the complete victory of gravity. They're
(20:20):
dead stars in a sense, no longer fusing elements, no
longer shining with their own nuclear fire. Yet they're far
from inactive. They spin, they pulse, they emit radiation, they quake,
and when they meet, they create explosions that seed the universe.
With the elements necessary for planets, for life, for consciousness itself.
(20:42):
Every pulsar pulse we detect is a message from the extreme,
a photon that traveled perhaps thousands of years across space,
carrying information about conditions we can barely comprehend. And every
time we detect those pulses, measure their timing, track their changes,
we're learning something new about the universe's most extreme physics.
These objects are poetry written in nuclear matter, a testament
(21:07):
to the fact that the universe is stranger, more extreme,
and more wonderful than we ever imagined when we looked
up at the steady, unchanging stars. Thank you for listening
to this episode off Black Hole. If you enjoyed exploring
the universe's most extreme matter, please subscribe to stay updated
on future episodes. This episode was brought to you by
(21:29):
Quiet Please Podcast Networks.
Speaker 1 (21:32):
For more content like this, please go to Quiet Please
dot ai Quiet, Please dot Ai hear what matters.
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