We know how terrifying and powerful black
holes can be, but what comes second place
in terms to it in terms of overall awesomeness?
Join us today as we learn about neutron stars!
One of the most popular outer space entities
that pop culture love to revolve about is
the black hole.
We’ve seen various movies, TV programs,
even some songs talk about how magnificent
and mysterious they are.
But what if black holes aren’t the only
objects that we should be amazed with?
Of course we have a lot of picks for that
matter, but the particular thing we would
talk about today is the star that ranks number
1 in the universe in terms of density: the
neutron stars.
Okay, astro fans, I can hear you argue and
say “No, black holes are the densest objects
in the universe!”
But let me tell you this: remember how black
holes work?
They are effectively stars that collapsed
to an almost zero volume, which results in
their enormous gravitational force.
If they effectively are dimensionless, can
we really say that they are “objects”?
We can’t be really sure, and that’s something
that only philosophy can answer, but while
we’re here at the subject of definitions
and what we actually know for certain, let’s
just say the one we can categorize as the
densest object, quote-unquote, is the neutron
star.
And no, a neutron star is not a subatomic
particle which grew to the size of the star.
It isn’t also a bunch of neutrons agreeing
to somehow collectively come together to form
a humongous star.
Although we can effectively say that a neutron
star is like a giant atom, we'll get to that
later.
For now, I want to discuss how neutron stars
are born and why they are like Phoenixes:
how from the ashes of their old corpses, they
rise up and fly with their new, replenished
lives!
I know you already know this if you’re an
astro buff, but to some of our viewers out
there who are new, first of all, welcome!
We hope we spark your curiosity more through
our videos!
Anyway, stars were discovered to follow some
kind of lifecycle, just like us living beings
on Earth.
They too, get born, have a childhood phase,
then grow to adulthood, then also die, after
certain circumstances.
A star’s usual routine involves fusing hydrogen
into helium.
Quite honestly, in its lifetime, that’s
all it ever does.
Now, as we know from basic nuclear physics,
when we fuse atoms together, it creates energy.
The energy that the fusion in the star creates
is countered by the gravitational force towards
its center, effectively keeping the balance
and preventing it from collapsing towards
its center.
As long as this goes on, everything is good
and well at a star’s life.
But of course, like all lives, stars experience
a tipping point in theirs.
Remember how stars burn hydrogen to fuse to
helium?
Well, eventually, stars run out of hydrogen
to fuse, so they fuse helium instead, forming
elements such as carbon and oxygen.
The energy pushes out the borders of the star
causing it to move to its giant phase, until
the pressure from electron degeneracy collapses
the core of the star, and expelling its outer
layer leaving a white dwarf.
For heavy mass stars, a number of times larger
than the mass of our own Sun, the story is
different.
The same as earlier, when the star runs out
of hydrogen to fuse, it begins to fuse heavier
elements.
The difference this time is that the collapse
caused by gravity is so extremely strong,
way stronger than what we described earlier,
that the fusion goes to Neon, to Oxygen, to
Silicon, then finally to Iron.
As this happens, the outer layer of the star
begins to fatten up faster as time goes by.
When the core of the star is finally iron,
fusion can no longer take place, as iron is
stubborn this way.
We can imagine at this point, there is no
more energy resulting from fusion.
So what if that happens?
The own weight of the star collapses in itself,
effectively crushing it to the size of up
to around a 10 kilometer radius.
It’s like compressing the star to about
the size of Malta!
Now, we know how subatomic particles don’t
want to get near each other, right?
We can practically say that an atom is made
of empty space.
However, the strength of the gravitational
force that occurs when a heavy mass star collapses
crushes this space in between, merging the
protons and electrons together to form neutrons,
with some neutrinos in excess.
But the extravaganza of energy doesn’t end
there!
See, neutrons hate being compressed towards
one another, too.
Just like protons and electrons.
The collapse can only occur up to a certain
moment where the neutrons form a lattice-like
structure, the crushing in stops.
By the way, this sudden halt is what we call
neutron degeneracy pressure.
The energy from this event results in a massive
supernova, outshining anything else in the
galaxy.
What’s left behind is a cloud of plasma,
from the ashes of the former star, rises the
old core, now what we call a neutron star:
the most dense object in the universe, after
the black hole.
I hope you still remember the thought earlier
whether we can call a black hole an object
or not.
What do you guys think?
Can black holes be considered as objects?
Leave us an answer in the comment section
down below!
You may be wondering, just how dense these
neutron stars are and why they are the next
most extreme objects in the universe after
a black hole.
Well, to put things in perspective, let’s
say for some reason, you can acquire a part
of a neutron size about the size of a sugar
cube.
That small chunk you have in your hand contains
the mass of all the living humans on Earth!
Imagine how sweet that would make your coffee!
Or tea, if you’re British.
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Okay, let’s carry on detailing more about
our stellar Phoenix, shall we?
The density of a neutron star is tremendously
large.
In fact, if it were to become a bit denser
than it already is, the gravitational force
would again tip the scales and collapse it
to a black hole.
Due to the same reason, it can also cause
ripples in space time and bend light around
it.
The surface of the star is also extremely
hot!
Around 600000 K to be exact.
To put things in perspective, Carbon, the
most difficult object to turn to gas, will
sublimate at around 3900 K. I think if everything
on earth is to be placed on the surface of
a neutron star, we would instantly vanish.
That is, if the strong gravity doesn’t tear
us up to pieces first.
Now, that’s hardcore!
But okay, a neutron star is the core of another
star, but if we have a hypothetical astronomical
surgical knife strong enough to cut it open,
what things are we bound to find inside?
Surprisingly, it is said that we are bound
to find planet-like characteristics inside
neutron stars.
Firstly, after we peel off the hot atmosphere,
we’re bound to find an iron-hard crust made
of...well, iron.
Because if you recall earlier, the elements
in the star are essentially squeezed tightly
to become ferrous.
Naturally, it is fair to expect the crust
to be like this.
Now, as we drill deeper into the star, we
are bound to see just how tightly gravity
compressed the parts of the old star together.
In the next “level” of the crust, we are
bound to see a few atoms clump together, forming
what looks like oval-shaped lumps.
Because of how it’s hypothesized to look,
scientists called this the gnocchi phase.
As we go deeper, the gnocchis of atoms are
now crushed further in long rod-like fashion,
forming the spaghetti phase.
Finally, at the last place before the core,
the nuclei are now expected to form a flat
layer, forming the last variety of pasta in
our example, the lasagna phase.
And collectively, these layers of deliciousness,
I mean, of the neutron star's crust form what
scientists call -- surprise, surprise -- nuclear
pasta: the most unbreakable material in the
universe.
At least in theory.
Okay, now that we’re done being hungry because
of all that pasta talk, let’s move on to
what could be in the core of a neutron star.
Well, at this point, scientists run out of
pasta to describe what goes on.
Not because there isn’t anymore comparison,
but because no one knows for sure what it’s
gonna be made of.
Some thought that the nucleons break down
into strange quarks, forming a sea of strange
matter.
Some infer that the protons and neutrons retain
their forms and just swim about in this extra
dense pool of energy and mass.
But whatever it is, I think we can all agree
that it is something worth looking forward
to...especially if it's going to be analogous
to another pasta variety!
It’s common knowledge in astrophysics that
stars exhibit some kind of orbital motion,
and when an object rotates, it exhibits angular
momentum.
The neutron star, being part of an older,
already spinning star, inherits this characteristic.
But before I discuss that any further, let’s
take a bit of a stroll to watch a skater perform
a spin.
When the skater’s arms are widely spread,
she spins at a really slow pace.
However, when she draws her arms closer to
her body, she begins to spin faster.
From that visualization, we can notice that
objects spin faster when they have a shorter
radius.
Okay, back to the neutron star.
From being a supergiant, to having a diameter
about the size of a regular city, we can imagine
how drastic the change in radius is, and therefore,
the change in angular speed?
A neutron star has to be spinning really fast,
as much as multiple times per second.
Moreover, it's not just the rotational speed
of the star that received a boost.
The magnetic field does as well.
Just how strong was the increase, you ask?
Well, let’s say a neutron star suddenly
popped into existence about halfway from the
moon to the Earth.
The magnetic field exhibited by that neutron
star is enough to erase all the credit card
information here on the planet.
The ultimate hacker!
Scientists initially doubted the existence
of these objects until it was verified by
a graduate student named Jocelyn Bell in 1967.
At the time when she was helping build a telescope
and discovered certain noises from their observations,
which as it turned out apparently were actually
Pulsars.
If you’re creative enough, it’s easy to
deduce that the name pulsar came from the
combination of the terms pulse and star, which
is exactly the nature of these objects.
A pulsar is a neutron star spinning with a
speed so fast and a magnetic field so strong
that beams of light come out from the poles
of this star.
This is what caused the “noises” that
Bell observed in her data: the telescope recorded
periodic flashes of light akin to a pulse,
which turns out one beam of light approaching
the earth from a neutron star lightyears away.
It’s like a nonsensical intergalactic Morse
code!
Now, there are moments where the magnetic
field increase in a neutron star can set to
hyperdrive, even going as much as about 10
to the 15 stronger than the Sun’s own magnetic
field.
These objects are named magnetars.
Although this feature causes this neutron
star to slow down its own spin, it’s still
a force not to be reckoned with.
When a magnetar releases its own stellar flare,
it could be felt billions of kilometers away.
In 2004, a satellite named SWIFT, built specifically
to detect powerful x-ray sources momentarily
went offline despite not pointing to anywhere
in particular to measure x-ray magnitude.
Turns out, the burst felt by the satellite
came from a magnetar about fifty thousand
lightyears away from the Earth.
It also briefly messed up with our own magnetosphere
and partially ionized the upper atmosphere.
Imagine just how strong that energy is to
cause a detectable effect to us even though
we’re literally as far as we can be from
it!
But despite the level of unimaginable strength
this type of neutron star has, they’re an
extremely rare breed in the galaxy.
Scientists estimate that there might just
be over a dozen magnetars all in all in the
whole universe...at least in the whole observable
universe.
Moreover, since they are relatively few in
number, the catastrophic effect of a magnetar
burst can be rarer.
I mean, we practically already have the technology
dedicated to detecting and studying these
types of stars.
If they occur as often as we initially thought
they would, we would have picked up something
already at this point.
I bet at this point you’re pretty amazed
by how fascinating neutron stars can get.
We thought the flat earthers are the densest
items in the whole universe, but today, we
learned differently and discovered that even
them fail to even remotely match the density
and the level of awesomeness that the neutron
star carries!
We hope that we discover more about these
stars in the future, and even though the answers
we get bring more questions, it would still
be wonderful to be living in a time where
these kinds of information are within our
grasp!
But enough about us, we want to know what
you think.
Do you guys think the neutron stars are the
most extreme, and most powerful objects in
the universe?
Let us know in the comment section down below!
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