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The Black Hole theory Episode#1 Schwarzschild radius


Hello, cybercitizens,
welcome to AVK classes now we know that most of our viewers are curious
about everything Some of us are very curious about astronomical
things and desire to know how the universe works
but whether you are a fan of astronomy or not you may be curious about this thing called
black hole so we have decided to make a mini-series covering
theories about black holes in our new section called the black hole theory
This is the first episode of the series so stay tuned to get even more smarter
and don’t forget to flex the brain muscles because we are going to get started,
the things we know about Black holes are that they are very heavy astronomical objects
they have a very high gravitational force so high that even light can’t escape its gravity
etc But we know that most of the object in universe
has mass and anything that has mass will try to pull less massive objects towards itself
because that’s how gravity works but the major difference between a black hole
and a normal object is not that it is black in colour but something related to its geometry
called Schwarzschild radius what is Schwarzschild radius you may ask
The Schwarzschild radius (sometimes historically referred to as the gravitational radius) is
the radius of a sphere such that, if all the mass of an object were to be compressed
within that sphere, the escape velocity from the surface of the
sphere would equal to the speed of light. that means it becomes a black hole. so Black hole is not just a massive object
but it is also a denser So that means theoretically it is possible
to make black hole even in your lab all you need is this equation
this is the equation of Schwarzschild radius As you know Schwarzschild radius is the distance
from the centre of a black hole to a point below which nothing, not even light can escape
this is also called event horizon And how big it is only depends on the mass
of object since G and C square are constants So heavier the black hole bigger the Schwarzschild
radius now you can use the Schwarzschild radius equation
to find Schwarzschild radius of day to day objects
for example, you wish to convert an object having mass 100 kg to a black hole all you
need to plug in the values and you will get the Schwarzschild radius
this means you have to compress the object to such a very low radius to turn it into
a black hole that’s impossible you think. its not
when supergiant starts to die, their supernovae explosions are so powerful that they compress
the core of the stars past their Schwarzschild radius
turning them into black holes but now you might not be having supernovae
strength compression then you can instead make a black hole by adding more mass to your
object as we know mass is nothing but product of
the density and volume of the object in question the equation that you will be needing is here
here we will rearrange the equation so that we will find the radius with respect to mass
now the radius of the object with a given density is proportional to cube root of its
mass and as stated earlier Schwarzschild radius
of an object is proportional to its mass so on adding mass the Schwarzschild radius
of an object will increase much faster than its actual radius
now initially the Schwarzschild radius of an object is very small as compared to its
actual radius but if we keep on adding mass, at some mass
the objects actual radius will become Schwarzschild radius thus it becomes a black hole
For earth which has a density of rock, this tipping point occurs at radius of 140 million
kilometres basically the distance to the sun so you can turn any given object into a black
hole, well at least in theory, just by knowing its density and volume. So by calculations, For earth, you have to
add mass up to a radius of 140 million kilometres before it turns into a black hole
That’s it from the first episode of this mini-series, stay tuned for the next episode
if you liked it hit the thumbs up button to let us know,
please comment below, If you have any comments, suggestions and ideas for future episodes
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below. Thank you for watching. Hope this video created a spark in your grey
cells and helped you to understand the intricacies We will meet again soon with another video
till then stay curious and keep learning. Thank you

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