neutron stars are one of the most
extreme and violent things in the
universe
giant atomic nuclei only a few
kilometers in diameter
but as massive as stars and they owe
their existence
to the death of something majestic
[Music]
stars exist because of a fragile balance
the mass of millions of billions of
trillions of tons of hot plasma
are being pulled inwards by gravity and
squeeze material together with so much
force
that nuclei fuse hydrogen fuses into
helium
this releases energy which pushes
against gravity
and tries to escape as long as this
balance exists
stars are pretty stable eventually
the hydrogen will be exhausted medium
stars like our sun
go through a giant phase where they burn
helium into carbon and oxygen
before they eventually turn into white
dwarfs
but in stars many times the mass of our
sun things get interesting when the
helium is exhausted
for a moment the balance of pressure and
radiation tips
and gravity winds squeezing the star
tighter than before
the core burns hotter and faster while
the outer layers of the stars swell by
hundreds of times
fusing heavier and heavier elements
carbon burns to neon in centuries
neon to oxygen in a year oxygen to
silicon in months
and silicon to iron in a day and then
death iron is nuclear ash
it has no energy to give and cannot be
fused
the fusion suddenly stops and the
balance ends
without the outward pressure from fusion
the core is crushed by the enormous
weight of the star above it
what happens now is awesome and scary
particles like electrons and protons
really don't want to be near each other
but the pressure of the collapsing star
is so great
that electrons and protons fuse into
neutrons which then get squeezed
together
as tightly as in atomic nuclei
an iron ball the size of the earth is
squeezed into a ball of pure nuclear
matter the size of a city
but not just the core the whole star
implodes
gravity pulling the outer layers in at
25
the speed of light this implosion
bounces off the iron core
producing a shock wave that explodes
outwards and catapults the rest of the
star into space
this is what we call a supernova
explosion
and it will outshine entire galaxies
what remains of the star is now a
neutron star
its mass is around a million times the
mass of the earth but compressed to an
object about 25 kilometers wide
it's so dense that the mass of all
living humans would fit into one cubic
centimeter of neutron star matter
that's roughly a billion tons in a space
the size of a sugar cube
put another way that's mount everest in
a cup of coffee
from the outside a neutron star is
unbelievably extreme
its gravity is the strongest outside
black holes
and if it were any denser it would
become one
light is bent around it meaning you can
see the front and
parts of the back their surfaces reach a
million
degrees celsius compared to a measly six
thousand degrees for our sun
okay let's look inside a neutron star
although these giant atomic nuclei are
stars
in many ways they're also like planets
with solid crusts over a liquid core
the crust is extremely hard the
outermost layers are made of iron left
over from the supernova
squeezed together in a crystal lattice
with a sea of electrons flowing through
them
going deeper gravity squeezes nuclei
closer together
we find fewer and fewer protons as most
merge to neutrons
until we reach the base of the crust
here nuclei
are squeezed together so hard that they
start to touch
protons and neutrons rearrange making
long cylinders or
sheets enormous nuclei with millions of
protons and neutrons shaped like
spaghetti and lasagna
which physicists call nuclear pasta
nuclear pasta is so dense that it may be
the strongest material in the universe
basically unbreakable lumps of pasta
inside a neutron star can even make
mountains
at most a few centimeters high but many
times as massive
as the himalayas eventually beneath the
pasta
we reach the core we're not really sure
what the properties of matter are when
they're squeezed this hard
protons and neutrons might dissolve into
an ocean of quarks
a so-called quark gluon plasma some of
those quarks
might turn into strange quarks making a
sort of
strange matter with properties so
extreme that we made a whole video about
it
or maybe they just stay protons and
neutrons
no one knows for sure and that's why we
do science
that's all pretty heavy stuff literally
so let's go back out into space
when neutron stars first collapse they
begin to spin
very very fast like a ballerina pulling
her arms in
neutron stars are celestial ballerinas
spinning many times per second
this creates pulses because their
magnetic field creates a beam of radio
waves
which passes every time they spin these
radio pulsars are the best known type of
neutron star
about 2 000 are known of in the milky
way
these magnetic fields are the strongest
in the universe
a quadrillion times stronger than
earth's after they're born
they're called magnets until they calm
down a little
but the absolute best kind of neutron
stars are friends with other neutron
stars
by radiating away energy as
gravitational waves ripples and
space-time
their orbits can decay and they can
crash into and kill each other
in a kill and over-explosion that spews
out a lot of their guards
when they do the conditions become so
extreme that for a moment
heavy nuclei are made again it's not
fusion putting nuclei together this time
but heavy neutron-rich matter falling
apart and reassembling
only very recently we've learned that
this is probably the origin of most of
the heavy elements in the universe
like gold uranium and platinum and
dozens more
so then our two neutron stars collapse
and become a black hole
dying yet again not only do stars have
to die to create elements they have to
die
twice over millions of years
these atoms will mix back into the
galaxy but some of them end up in a
cloud which gravity pulls together
to form stars and planets repeating the
cycle our solar system is one example
and the remains of those neutron stars
that came before us
are all around us our entire
technological modern world
was built out of the elements neutron
stars made in eon's past
sending these atoms on a 13 billion year
journey
to come together and make us and our
world
and that's pretty cool
[Music]
until then we can look at them on paper
the 12020 human space era calendar has
arrived
you can order it now until we sell out
and then
never again visit the cloudy cities of
venus
dyson swarm assembly on mercury and
cross the borders of our solar system
shipping from the u.s and from europe
for the first time
but we deliver to every country all over
the world
you could also get a plushie or hoodie
or poster
we have some sweet deals for you get it
for christmas for your friends families
and kids
or to distract yourself from the fact
that there are 100 billion billion
earth-like planets in the habitable zone
of sun-like stars in the observable
universe
and you will never visit any of them the
last few years we've sold them all so no
rush but the clock is ticking
getting stuff from our shop is one of
the best ways to support kotzkazad
because of you we can keep this channel
free for everyone
and make more beautiful things a happy
interstellar year
[Music]
12020