Hello guys and welcome to my new video.
This video is on primordial black holes.
So don't resemble this black holes with the
ordinary black holes these are completely
different black holes, so I request you to
please watch this whole video this gona be
very interesting.
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Now let's start this video.
The theory of black holes was first proposed in 1966, by two
Soviet physicists.
Since After that there are many theories have
been introduced on black holes.
Astronomers categorise all these black holes
into three types: Stellar mass black holes,
intermediate mass black hole and supermassive
black holes.
But there is also an another type of black
holes which astronomers haven't yet seen,
but think could exist.
These are primordial black holes.
The size of these black holes can range from
hundred thousand times less then a paper clip
to about hundred thousand times greater than
the sun.
It has been calculated that black holes having
mass lower than a planet, would not have survived
to present, due to Hawking radiation.
The theory of primordial black holes are seen
as a key source for finding the dark matter
because there are few properties of black
holes which resemble with that of dark matter,
like they don't emit light, not even
they moves at speed of light and like dark
matter, black hole are also cannot be directly
detected.
We know that about 85% of missing mass of
this universe is contained within this dark
matter.
So this theory tells us that, these dark matter
consists of tiny primordial black holes, which
contain the major mass of these dark matter.
But there is one problem in this concept.
Black holes are formed by the the death of
stars, which were not yet present in the primordial
universe.
Since the presence of dark matter is necessary
in the history of universe.
So, here the question still remains that,
how did the primordial black holes originated?
The theory behind their origins was first
studied by Stephen Hawking in 1971.
Primordial black holes were born very early
in the life of the universe, mere a fraction
of a second after the big bang because the
space was not completely homogeneous, some
areas were denser and hotter than others and
these
dense regions could have collapsed into black
holes.
Suppose that somehow these black holes came
into existence after Big Bang, so how we can
find them now?
The main purpose behind the detection of these
black holes is to find out their masses.
So, there are many ways through which we can
detect these black holes.
But, I will discuss only three of them and
the other will be mentioned in the description.
I will make you understand this by an example.
suppose that we are observing a star for a
long period of time.
So, it makes possible that when a compact
non luminous object passes between us and
observe star, it become easily noticeable,
because it's luminosity is temporary amplified.
But this theory is not quite acceptable because
we cannot verify that which type of object
is passing between us and that observed star.
So, this theory is not much satisfactory for
the detection of the primordial black holes.
After Big Bang Theory when primordial black
holes were formed the matter accretion onto
primordial black holes leads to the emission
of high energy photons which affects the recombination
history of this universe.
This, in turn, affects the statistical properties
of the cosmic microwave background anisotropies.
So, the observations of these cosmic microwave
background excluded that primordial black
holes may have mass in the range of about
100 to 10000 solar masses.
The most mysterious object of the Cosmos are
the supermassive black holes.
None of the scientists have claimed with
surity that how these black holes were formed.
Since our universe is not too much old.
The stars which were burst and formed the Universe first Black Holes
So, for the head not got so much time or material,
so that they can become supermassive black holes
These black holes are minions or billions
times the mass of the Sun, they can't be created
by one or even several exploding stars.
Astronomers don't know how these black holes
got in the centre of massive galaxies and
what created them, perhaps they are built
from primordial black holes, serving as seeds
out of which supermassive black holes could
grow.
In March 2016, when gravitational waves were
first detected by LIGO, one thing came to
great effect that, perhaps, the two colliding
black holes are probably a primordial black
holes.
The masses of the two black holes were calculated
of about 30 solar masses.
This incident strong revived interest in primordial
black holes, which having masses between 1
to 100 solar masses.
In August 2019, a research team had published
that primordial black hole having mass between
this to this had the possibility of making
up all dark matter.
In September 2019, a report was proposed that
a primordial black hole about the size of
a tennis Ball exist in the Kuiper belt of
our solar system.
They tried to explain the orbital anomalies
that are theorized to be the result of a ninth planet
Scientists are using the Fermi Gamma ray space
telescope to observe the small interference
patterns within Gamma ray bursts.
So that they could get the evidence of primordial
black hole which can also prove the string
theory.
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