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stars are among the most fascinating
things in the universe they are the
givers of warmth light and energy and
are the nuclear engines behind some of
the most extreme phenomena they form
from gas clouds and carve out entire
planetary systems releasing heavier
elements in the process which allow more
stars to form but the most fascinating
thing about stars is what awaits them
when they die when a star reaches the
end of its life most of the time it does
so in incredible fashion with a blinding
cataclysmic supernova explosion but that
is rarely the end we know that
particularly massive stars many
thousands of times larger than our Sun
can collapse in on themselves so much
that they form black holes but a dead
star doesn't always have to form a black
hole to be a destructive gravitational
influence some stars collapse down to a
fraction of the size they once were into
a ball of tortured matter so dense and
compressed that the effects are out of
this world
quite literally these dense graveyard
star cores are known as neutron stars
and their types properties and
statistics are all absolutely
mind-numbing
in order to understand what a neutron
star is you must first understand what a
neutron is everything in the universe
besides energy is composed of atoms the
tiny fundamental building blocks of
creation and they themselves are made up
of tiny components called subatomic
particles which come in three varieties
protons which have a positive electrical
charge electrons which have a negative
electrical charge and finally neutrons
subatomic particles with no net
electrical charge protons and neutrons
make up the nucleus of an atom and the
number of each is the same in most
elements so with that in mind how does
it relate to dead stars well a neutron
star is formed when a massive star
between ten times and 29 times the mass
of our Sun reaches the end of its life
and explodes at this point heavier
elements in the core begin fusing iron
because iron has no energy to give
fusion is no longer
rating outward pressure from within the
star and there is suddenly nothing to
stop the star collapsing under the
weight of its own gravity the outer
layers collapse inwards rapidly with
nothing to counter them and when they
reach the iron core this matter forces
the interior into a much smaller space
before essentially bouncing off the core
and exploding in a violent supernova
explosion these outer layers collapse
fast at 25% the speed of light in fact
this is so fast that particularly
massive stars keep on collapsing
indefinitely into a singularity creating
a black hole a neutron star is formed by
the level of massive star below star
cores that are less than about four to
five times the mass of the Sun in this
case the core is not massive enough to
collapse indefinitely but what remains
at the collapse matter is miniscule in
size compared to its previous form a
star wants hundreds of times larger than
the Sun collapses into an object the
size of a city making it among the
densest objects in the universe the
reason they are called neutron stars is
because the density and pressure on the
interior is so great that the protons
and electrons of the atoms within starts
be crushed into one another generating
long chains of strong Neutron rich
material under conditions similar to
those of the nucleus of an atom neutron
stars are essentially giant atomic
nuclei these dense dead stars have
extremely strong gravitational
influences and magnetic fields the chain
reaction from the supernova explosion
often causes the newly formed neutron
start to spin incredibly quickly with
some known to rotate up to 40,000 times
per minute a speed which begins to
deteriorate over time it wasn't until
the 1960s that we were able to confirm
the existence of these unthinkably dense
objects but scientists have been
speculating on them for some 30 years or
so in the time leading up to their
discovery in December 1933 just two
years after the discovery of the neutron
astrophysicists Walter Baade and Fritz
Viki proposed that supernova explosions
could cause stars to turn into much
denser more closely packed bodies as a
result of the explosion a plausible
theory but at the time we were sure we'd
never be able to detect such an object
even if they did exist as they would
simply be too small to be observed from
the earth
but moving into the 1960s astronomer
Franco pussini noted that if stars
generated strong magnetic fields then
the electromagnetic radiation this would
emit should be detectable from the earth
and sure enough in 1965 astronomers
Antony Hewish and Samuel Okoye
discovered a source of radio brightness
in the nearby Crab Nebula this anomaly
turned out to be the product of a
rapidly rotating neutron star and so we
were able to conclude on the existence
of these terrifying postproduction stars
and then in 1997 we did in fact see a
neutron star through visible light what
you see here is an actual photograph of
a neutron star of a similar mass to our
Sun which was discovered in 1992 the
achievement of observing a neutron star
400 light years away in visible light is
not to be understated where as stars are
millions of kilometers in diameter and
radiate light most neutron stars are
merely about twenty kilometres in
diameter or just twelve miles one of the
largest we've discovered today is PSR
jo3 for a a neutron star in the
constellation of Taurus with an
estimated mass of about twice that of
our Sun packed into an object just 25
kilometers wide making it smaller than
the inner ring roads of the city of
London but huge for a neutron star
although saying that size doesn't
actually correlate to more mass within
neutron stars in fact more massive
neutron stars are actually smaller as
their mass compacts more densely than
inlighten neutron stars regardless of
how big or small they are this size mass
ratio gives them their incredible
densities so much so that a single
teaspoon of neutron star matter would
weigh hundreds of millions of tons here
on earth this incredibly compact
concentration of mass means that the
gravity of a neutron star is around two
billion times greater than on the earth
and while not as dense as black holes
this gravity is still enough to bend and
warp the radiation and light being
emitted around it causing a
gravitational lensing effect in fact
sticking with our teaspoon of neutron
star material if you were able to drop
it to the ground from shoulder height
the spoon would be traveling at well
over 20,000 kilometers per hour before
it collided with the ground
our ideas on the nature of these stars
is based on models but it is possible to
infer some details of a neutral style
structure by studying living stars such
as the Sun this process is known as
Astro seismology and it can reveal the
inner structure of neutron stars by
analyzing the spectra of star
oscillations this is what gives us our
insight into the real jaw-dropping
numbers associated with these cocoons
the surface or crust of the neutron star
is an extremely hard outer layer whose
surface temperature can reach up to 1
million degrees Kelvin this crust gives
the neutron star a miniature landscape
it can have mountains but these
mountains can only ever hope to reach a
few millimeters high the extreme outer
layer is made mostly of iron leftover
from the supernova and this iron is so
compressed that it keeps the internal
components sealed below the crust and
unthinkable pressure under these
conditions atomic nuclei are crushed
together in long strings of matter
trivially named nuclear pasta barely
anything can breach this material there
is among the strongest the most tightly
packed matter in the universe as we move
downwards towards the core we start to
become a bit less sure we aren't sure
what effect this much pressure this deep
into the core would have or matter
however we do know that it is able to
keep atomic nuclei from decaying
allowing it to remain stable this
internal mass density and pressure keeps
any atmosphere the neutron star has
tightly pressed onto the surface only a
few micrometers thick and this is
controlled by the incredible magnetic
field produced by the neutron star the
magnetic field of a neutron star can be
anywhere between 100 million and one
quadrillion times stronger than the
Earth's making them the most powerful
magnetic fields in the known universe
every neutron star has its own
terrifying density mass and attraction
and there could be as many as 100
million of them in our galaxy alone most
of these are old cold neutron stars
which formed billions of years ago but
some of them are young and display
unique characteristics especially if
they are rotating all neutron stars emit
beams of radiation from their north and
south poles and if those rotating
emission points happen to be firing in
the direction of the earth and we can
detect these as
pulses of light just like relativistic
Jets firing away from crazy ours
when these plumes point in the direction
of the earth we can detect them from
immense distances when this happens
these neutron stars often resemble
lighthouses firing beams at a consistent
rate in the direction of the earth from
all over the galaxy when this happens we
call these firing neutron stars pulsars
and their rotation rates vary depending
on their age and what's in their
surrounding area some can rotate
thousands of times every second we call
the most rapid ones millisecond pulsars
with the fastest reaching speeds of up
to 65% the speed of light the word
pulsar literally means pulsating star
and they are named as such because of
the pulsing sound they make as the beams
sweep across the planet in sequence
following the first noting of neutron
stars in 1965 by Antony Hewish two years
later he and his assistant Jocelyn Bell
Burnell
detected a radio signal which appeared
to be pulsing at a consistent rate with
exquisite precision in fact this signal
seemed so consistent and anomalous that
it prompted widespread speculation that
bernal had intercepted a transmission
from an alien civilization and so the
signal was named Appel gm1 an acronym of
little green men however we soon
realized that this was in fact a
rotating neutron star emitting beams of
radiation in the direction of the earth
since then we have discovered nearly
2,000 of these pulsars and most a
cataloged as part of radio surveys hence
why many of them are named with the
prefix PSR for pulsar and so lgm1
during the growing list of astronomical
phenomena initially attributed to aliens
but was actually a result of something
natural but fear not these nuclear
lighthouses may yet be of use in the
discovery of our species
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the Voyager 2 spacecraft is a probe
which was launched in 1977 to explore
the distant ice giant planets but since
completing this mission it now barrels
through interstellar space carrying with
it a golden record this record is
mankind's CV it was meant to be found by
aliens it contains information about our
location in the galaxy this map was
created using pulsars as a point of
reference because they are extremely
good timekeepers while their positions
may change over time their pulse
frequency remains highly consistent so
the idea is that a civilization could
look at this map which shows the
position of earth relative to fourteen
nearby pulsars and they could find these
pulsars based on their pulsation rates
which we have attempted to inscribe on
the record and then reverse-engineer our
position it's a genius idea or at least
it seemed that way in 1977 but in the
years since we have learned that there
could be hundreds of millions of these
pulsars in the galaxy and though their
rates are relatively consistent and
measurable the direction in which they
fire can change unpredictably meaning a
bright beacon which once illuminated the
earth with flashes of radio energy may
just become another silent speck in the
night sky finding 14 coincidentally
placed pulsars in a galaxy with
potentially billions
it isn't even comparable to the needle
and haystack analogy so whatever and
whoever Voyager might encounter on its
journey they'll likely never be able to
work out where the probe came from even
if they managed to decipher the map the
faster a neutron star rotates the
stronger the magnetic field it generates
and for those exceptionally extreme
neutron stars there is another
classification a magnetar
these are similar in size and mass two
neutron stars but rotates so fast that
they are even more extreme and deadly
magnet ours can be caused by the
supernova that created it or by the
gravity of a neighbor around the neutron
star whatever the case their magnetic
fields are amplified exceeding 1,000
times the strength of a normal neutron
stars field which is already billions of
times the strength of the Earth's it's a
scale difficult to fully appreciate
these fields are so intense that they
often experience very strong x-ray
bursts and when their shells crack
blasts of x-ray and gamma radiation are
emitted this can cause an aptly named
star quake which can lead to a storm of
solar energy trillions of times more
powerful than the solar emissions of our
own star unsurprisingly these magnetized
are not very stable the strong magnetic
fields tend to break down after about
ten thousand years which is only the
blink of an eye on a cosmological
timescale and it is a much narrower
window for us to exist to observe them
therefore magnetized are considerably
rarer than neutron stars and pulsars
there are estimated to be about 30
million inactive magnet ours
based on the number we can currently
observe most neutron stars are old
spinning much more slowly than the young
magnet ours and millisecond pulsars so
the question is what happens to these
aging nuclear capsules over time do they
blow up collapse even further merge with
one another well the answer can be all
three loads of weird and wonderful
things can happen to a neutron star
especially if we give it a neighbor
neutron stars can continue to gain mass
and grow after formation and they grow
in the same way that planets and moons
do through accretion the gradual
accumulation of matter as the object
orbits neutron stars have an insanely
strong gravitational influence and
therefore attract a lot of extra mass
from their surrounding areas this
accumulation of mass can cause already
rapid pulsars to spin even faster it can
push young neutron stars into spin
cycles and it can wake up older slower
pulsars neutron stars attract the most
matter in binary star systems binary
systems are commonplace throughout the
galaxy stars form from the same
collapsing clouds of gas that form star
systems like ours and given their strong
gravitational influences it's not
uncommon to see stars in pairs orbiting
each other as such it's not uncommon to
see a neutron star in a binary star
system the most common type of neighbor
we see for neutron stars in binary
systems is a white dwarf the final light
of a dying star this could be because
both stars in the system are old all the
star has been stripped away and
irradiated by the Companions supernova
and
our orbits as a dying call or perhaps
the neutron star is a visitor magnet
ours barreling through space 1/5 the
speed of light can find homes in new
star systems and like a spider crawling
out of the dark these neutron stars then
enter the systems and strip away the
unlucky star down to its dying phase
most of the time
wherever the neutron star orbits will
bring it to a collision as it spirals
inwards however should the object which
orbits the neutron star managed to
remain a safe enough distance to avoid
total destruction than the other star
may survive to become a neutron star
itself suddenly there are two of these
incredibly dense powerful masses and
their gravitational interactions can be
felt from entire galaxies away where
binary neutron stars orbit each other
they spiral inwards and begin to draw
closer and speed up as they do in the
moments before they collide they reach a
significant percentage of the speed of
light and lose energy through
gravitational radiation this interaction
before the merging may be a source of
gravitational waves disturbances in the
curvature of space-time itself
gravitational waves are caused by to
accelerated masses they are like ripples
in the fabric of reality which fly away
from the source at the speed of light
and this is exactly what we think
happened when we detected gravitational
waves in 2017 GW 1708 17 is the catalog
name of a gravitational wave signal
which was detected by the advanced laser
interferometer gravitational-wave
Observatory or LIGO and scientists
believe that these ripples in space-time
are the result of two neutron stars
colliding in a galaxy over a hundred and
forty million light years away with
detectability across such vast distances
it should come as no surprise that the
actual collision is just as terrifying
and far-reaching when the two neutron
stars are within touching distance the
tidal gravitational forces of each
shatter the outer shells releasing the
enormous reserves of matter track within
into space which is under considerably
less pressure and explodes in an
appropriately named killer Nova
explosion this explosion is a source of
short gamma-ray bursts the most
destructive electromagnetic explosions
in the universe after this cataclysmic
explosion has take
place the two merging neutron stars will
do one of two things they will either
become a more massive neutron star all
the two masses will collapse and form a
black hole the lower bound mass limit
required to form a black hole is between
four or five times the mass of our Sun
if the two neutron star cores combine
but remain below this mass then they
will combine to form a magnet art with
the magnetic field trillions of times
stronger than the Earth's alternatively
the two dead stars will collapse in on
each other and form a black hole which
is infinitely dense a singularity it's
an intriguing and bewildering process
but the merger of neutron stars is
actually quite a fruitful event the
shattering of neutron star shells
releases loads of heavier elements which
were fused by the style that came before
it and these heavier elements mix into
the clouds of hydrogen and helium gas in
space the same clouds that form
planetary systems the remains of killing
over explosions is likely the source of
most of the heavy elements in the
universe and the solar nebula cloud
which our solar system formed from five
billion years ago likely contains the
remains of neutron stars which exploded
billions of years before in a profoundly
younger universe neutron stars are just
another tiny improbable piece of the
unendingly complex puzzle that is the
emergence of life from Stardust speaking
of planetary systems what would it be
like for a planetary system orbiting a
neutron star we've observed planets
around neutron stars before we detect
them when said planet passes in front of
the beams of a firing pulsar as such we
refer to them as pulsar planets and
we've known about them since 1991 and
have discovered entire planetary systems
orbiting them since then it's unlikely
that these were the planets that orbited
the star in the main stage of its life
on the contrary all of the pulsar
planets we have observed fall into three
main groups
the first being planets which formed out
of the metal-rich debris leftover from
the supernova explosion which formed the
neutron star all the planet could be a
captured planet the extreme gravity of a
neutron star may just be enough to pluck
a hurtling rogue planet out of the
darkness of interstellar space and into
orbit damming it to be radiated and
ravaged by its new deceased host or
three the planet might actually be the
other star in the bind
system which used to orbit the pulsar
but there has been stripped down and
solidified due to the extreme
irradiation of the Pulsar in 2011 we
discovered the companion of the pulsar
PSR j17 1:9 it was a white dwarf star in
the final stage of its life but it had
most of its mass torn off by the Pulsar
orbits and was spiraling inwards towards
its companion destined to be shredded up
and ripped to pieces
however this star orbits its neighbour
in an unlikely position a distance
slightly smaller than the radius of the
Sun just under 700,000 kilometers this
isn't close enough to shred the planet
entirely but the pulsars influence is so
strong that the carbon in the star has
likely crystallized the neutron
neighbour is now likely a diamond planet
five times the size of the earth life on
these neutron star planets is
non-existent and hopeless those planets
lucky enough to escape total destruction
as subjected to torturous conditions the
beams of gamma radiation x-rays and
extremely solar energy would ravage any
planet if a magnetar came within range
of our planet say about the distance of
the moon then you would start to notice
fast our atoms would be warped and would
change shape completely destroying your
molecular structure and dissolving your
body nothing can survive under the
vise-like grip of a pulsar or worse a
magnetar
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and so the final question is if neutron
stars are virtually unbreakable and
composed of the hardest materials in the
universe then what happens when the
amove will object meets its unstoppable
force what happens when a neutron star
is consumed by the only thing stronger
and more powerful than itself a black
hole well we may finally have an answer
only a few months ago did those same
gravitational wave Observatory Zin Italy
pick up more ripples in space-time more
gravitational waves created by a
collision a little under a billion
light-years away the signal is named
s-19 I ate one 4bv
and is believed to be the product of a
neutron star being eaten by a black hole
scientists analyzed the wave patterns
from the two objects and determined that
one of the objects must have exceeded
five solar masses while the other was
some way less likely meaning that this
is a black hole and neutron star pairing
although the distinction between the two
remains unclear in this case regardless
the waves were a product of the moments
before the collision as for the
collision itself well if the black hole
in question is large enough then the
neutron star could disappear over the
event horizon with one big gulp this
would release no energy beyond the
boundary and would be somewhat
anticlimactic if you were an observer
looking on from the outside in this case
however it's unlikely that the mass
difference between the two is sufficient
for the black hole to be capable of such
a large gulp so some impact would have
occurred the neutron star would be
ripped apart by gravity and its matter
would be dispersed in every direction
some of this matter falls straight into
the black hole whereas some of it may be
ejected beyond the event horizon are
immense speeds before falling back in
again some of the debris will be flung
out and will be under much less pressure
in space causing it to explode violently
the other debris won't escape entirely
but will fall into orbit around the
black hole along its accretion disk
so these gravitational waves likely did
emit from the site of a cataclysmic
explosion but probably a less impressive
explosion than when two neutron stars
collide as of yet we don't have any
visual confirmation
Aviva neutron stars are the seeds of
creation in the universe
tiny incubators of super dense heavy
elements and atomic nuclei they attract
they destroy and they emit beams of
radiation they produce the strongest
magnetic fields in the universe and a
second only to black holes in terms of
their properties and mysteries looking
into a black hole makes the gravity and
pressure within seem almost silent and
featureless but when we look at neutron
stars we know that the true conditions
are anything but
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