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Atoms As Big As Mountains — Neutron Stars Explained

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    Neutron stars are one of the
    most extreme things in the universe.
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    They’re like giant atom cores.
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    Kilometers in diameter,
    unbelievably dense and violent.
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    But how can something
    like this even exist?
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    The life of a star is dominated
    by two forces being in balance.
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    Its own gravity and the radiation
    pressure of its fusion reaction.
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    In the core of stars, hydrogen
    is fused into helium.
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    Eventually, the hydrogen
    in the core is exhausted.
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    If the star is massive enough,
    helium is now fused into carbon.
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    The cores of these massive
    stars become layered like onions,
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    as heavier and heavier atomic
    nuclei build up at the center.
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    Carbon is fused into neon, which leads
    to oxygen, which leads to silicon.
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    Eventually, the fusion reaction hits iron,
    which cannot fuse into another element.
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    When the fusion stops, the
    radiation pressure drops rapidly.
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    The star is no longer in balance,
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    and if its core mass exceeds
    about 1.4 solar masses,
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    a catastrophic collapse takes place.
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    The outer part of the core reaches
    velocities of up to 70,000 km/s,
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    as it collapses towards
    the center of the star.
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    Now, only the fundamental
    forces inside an atom
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    are left to fight the
    gravitational collapse.
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    The quantum-mechanical repulsion
    of electrons is overcome,
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    and electrons and protons
    fuse into neutrons
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    packed as densely as an atomic nucleus.
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    The outer layers of the star
    are catapulted into space
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    in a violent supernova explosion.
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    So, now we have a neutron star!
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    Its mass is between 1 and 3 Suns,
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    but compressed to an object
    about 25 kilometers wide!
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    And 500,000 times the mass
    of Earth, in this tiny ball
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    that’s roughly the diameter of Manhattan.
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    It’s so dense that one cubic
    centimeter of neutron star
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    contains the same mass as an
    iron cube 700 meters across.
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    That’s roughly 1 billion tons,
    as massive as Mount Everest,
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    in a space the size of a sugar cube.
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    Neutron star gravity
    is pretty impressive too!
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    If you were to drop an object from
    1 meter over the surface,
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    it would hit the star in one microsecond
    and accelerate up to 7.2 million km/h.
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    The surface is superflat, with
    irregularities of 5 millimeters maximum,
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    with a superthin atmosphere of hot plasma.
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    The surface temperature
    is about 1 million kelvin,
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    compared to 5,800 kelvin for our Sun.
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    Let’s look inside the neutron star!
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    The crust is extremely hard
    and is most likely made of
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    an iron atom nuclei lattice with a sea
    of electrons flowing through them.
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    The closer we get to the core, the more
    neutrons and the fewer protons we see
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    until there’s just an incredibly dense
    soup of indistinguishable neutrons.
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    The cores of neutron stars
    are very, very weird.
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    We are not sure what their properties are,
    but our closest guess is
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    superfluid neutron degenerate matter
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    or some kind of ultradense quark
    matter called quark-gluon plasma.
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    That does not make any sense
    in the traditional way
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    and can only exist in such an
    ultraextreme environment.
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    In many ways, a neutron star
    is similar to a giant atom core.
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    The most important difference is that atom
    cores are held together by
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    strong interaction
    and neutron stars by gravity.
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    As if all this wasn’t extreme enough,
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    let’s take a look at
    a few other properties.
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    Neutron stars spin very, very fast,
    young ones several times per second.
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    And if there’s a poor star nearby
    to feed the neutron star,
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    it can rotate up to several
    hundred times per second.
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    Like the object PSRJ1748-2446ad.
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    It spins at approximately
    252 million km/h.
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    This is so fast that the star has
    a rather strange shape.
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    We call these objects pulsars, because
    they emit a strong radio signal.
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    And the magnetic field of a neutron star
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    is roughly 8 trillion times stronger
    than the magnetic field of Earth.
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    So strong that atoms get bent
    when they enter its influence.
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    Okay, I think we got the point across.
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    Neutron stars are some
    of the most extreme,
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    but also some of the
    coolest objects in the universe.
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    Hopefully, we will one day send spaceships
    to learn more about them
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    and take some neat pictures!
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    But we shouldn’t get too close!
Title:
Atoms As Big As Mountains — Neutron Stars Explained
Description:

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Video Language:
English
Duration:
05:11

English subtitles

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