In past few decades,
there had been a lot of scientific discoveries
higgs boson
neutron star collision
and the first image of black hole "Powehi",
being some of them
but even after these discoveries,
we still don't have answers to alot of questions
one of them being "dark energy" itself
around 1990s, it was believed that
the universe was expanding
and only in 1998 it was made clear
by the observations of Hubble Space Telescope,
that this expansion was accelerating
and to explain this expansion,
physicists came up with
the dark energy hypothesis
and assumed that this hypothetical thing fills up the entire space uniformly!
But around  34 years earlier
in 1966, the research paper published in astrophysical journal was against this
it was published by russian physicist
Erast Gliner
and he believed that the dark energy is not everywhere in this universe
nor it is the property of spacetime
instead a very special kind of black hole is making the whole universe expand!
and today we're gonna know more about this black hole
so do stick around till the end
black holes are one of the most mysterious thing in the universe
but really this is not a "thing",
but it's that region of spacetime
where once used to be a star which collapsed
and now there is a singularity
due to huge gravitational time dilation near this region
whole electromagnetic spectrum is redshifted to radiowave region
which our eyes and modern devices can't detect/measure
and hence invisible
when a star is near it's final stage of life
and has almost finished up all it's fuel
then it begins to collapse.
*wait, quick question, why wasn't the star collapsing earlier?*
right, about that
before, the star had huge stock of hydrogen
which was undergoing nuclear fusion
and creating helium atom
and giving off photons and other particles as byproduct
and thanks to albert einstein
who taught us that,
even massless particle such as photon
can exert force due to it's energy
this force leads to a pressure, a.k.a. radiation pressure
which counteracts the gravity and keeps the star stable
but when, that fuel is almost up
the radiation pressure also begins to drop and the gravity starts taking over.
When the star is about 3 to  5 times more massive than our sun or greater
this collapse leads to the creation of an event horizon
at the center of the sun.
Slowly, this event horizon starts getting bigger
and everything which once was a part of this star gets sucked into it.
Normal stars which collapse
hide a singularity behind their event horizon
a theoretical point in spacetime, of which physics can't tell anything about
but some more massive stars, after collapse
don't form a black hole as such
and hide a singularity behind their event horizon!
it's not me who is claiming this, but leningrad (now known as st. petersburg)
physicist Erast Gliner is
such stars after collapsing gravitationally
do not form a black hole
but GEODE
GEneric Object of Dark Energy
from a distance these GEODEs resemble any black hole
but instead of a singularity they hide pure dark energy behind their event horizon
Gliner believed that,
if there is even 1 GEODE for 100 Black Holes in our universe
then it's enough to explain everything
about the observed expansion of our universe!
earlier it was believed that,
universe wasn't affected on what happens on small scale
i.e. universe doesn't care about what happens in our day to day life
we based friedmann model on this very assumption
which explains about the expansion of our universe
actually saying that universe is expanding, is grammatically wrong from Physics point of view
as it's not really expanding but scaling up!
for example, when you zoom in a "pic"
everything gets bigger
but at the same time, stuff get farther away from each other, right?
this is exactly what's happening with our universe
only difference being,
because of gravity, electromagnetism, and strong nuclear force
there is no change in the size of star, galaxies and planets
which leads to the illusion of this expansion of our universe.
But even the existence of GEODE
raises some questions on friedmann model
can we still trust it?
or does this need modifications?
This idea of GEODE is not only helping us with dark energy hypothesis
but can also be used to explain other problems like black hole collision
when both the stars of a binary star system collapse to form a black hole
and starts getting closer to each other due to their mutual gravitation
which results in them colliding
and forming an even bigger black hole
and give off alot of energy in the form of gravitational waves
we already knew about such collisions
and we also had some simulations of them
but in 2016 what LIGO
Lazer Interferometer Gravitational wave Observatory
detected was something else
the detected black holes in the collision were 5 times more massive than theoretical prediction
no one had a clue about how this could be happening
But if we assumed that instead of black holes this was a collision of GEODEs
of same theoretical mass (5 times less massive than observed)
then we could have explained this with ease
because the size of GEODEs get bigger as the universe expands
and by the time they collided, it would have gotten
so massive because of the expansion
that the resulting GEODE
would have been 4 to 8 time more massive
as observed by LIGO.
Right now, this is all very theoretical
and we don't know much about them
but I hope physicists dig deeper into the mysteries of GEODEs
and tell us more about them
so guys, let's meet up again in some other video
where we'll be discussing something like this
and friends, stay curious
and leave all your query with "?" symbol at the end in comment section
we'll answer them in upcoming videos
till then happy physic-sing!
